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GT STRUDL reg
Version 29
Release Guide
Volume 1 of 2
December 2006
Computer-Aided Structural Engineering Center School of Civil amp Environmental Engineering
Georgia Institute of Technology Atlanta Georgia 30332-0355
USA
Telephone (404) 894-2260 Fax (404) 894-8014
e-mail caseccegatechedu
- ii -
NOTICES
This GTSTRUDLreg Release Guide is applicable to Version 29 with a release date in theGTSTRUDL title block of December 2006
The GTSTRUDLreg computer program is proprietary to and a trade secret of the GeorgiaTech Research Corporation Atlanta Georgia USA
GTMenu and its documentation were developed as an enhancement to GTSTRUDLauthored by the Computer-Aided Structural Engineering Center Georgia Institute ofTechnology
DISCLAIMER
NEITHER GEORGIA TECH RESEARCH CORPORATION NOR GEORGIAINSTITUTE OF TECHNOLOGY MAKE ANY WARRANTY EXPRESSED ORIMPLIED AS TO THE DOCUMENTATION FUNCTION OR PERFORMANCE OFTHE PROGRAM DESCRIBED HEREIN AND THE USER OF THE PROGRAM ISEXPECTED TO MAKE THE FINAL EVALUATION AS TO THE USEFULNESS OFTHE PROGRAM IN THEIR OWN ENVIRONMENT
Commercial Software Rights Legend
Any use duplication or disclosure of this software by or for the US Government shallbe restricted to the terms of a license agreement in accordance with the clause at DFARS2277202-3 (June 2005)
This material may be reproduced by or for the US Government pursuant to thecopyright license under the clause at DFARS 252227-7013 September 1989
copy Copyright 2006Georgia Tech Research Corporation
Atlanta Georgia 30332-0355USA
ALL RIGHTS RESERVED
S)))))))))))))))))QGTSTRUDLreg is a registered service mark of the Georgia Tech Research CorporationAtlanta Georgiacopy Windows XP Windows 2000 Windows NT Windows ME and Windows 98 areregistered trademarks of Microsoft Corporation Redmond Washingtoncopy Excel is a registered trademark of Microsoft Corporation Redmond Washington
- iii -
Table of Contents
NOTICES ii
DISCLAIMER ii
Commercial Software Rights Legend ii
CHAPTER 1
Introduction 1-1
CHAPTER 2
New Features in Version 29 2-1
21 Data Base Exchange (DBX) 2-1
22 Dynamics 2-1
23 Elastic Buckling 2-5
24 General 2-6
25 GTMenu 2-13
26 GTSTRUDL Output Window 2-33
27 Model Wizard 2-38
28 Nonlinear Analysis 2-38
29 Nonlinear Dynamic Analysis 2-39
210 Offshore 2-39
211 Reinforced Concrete Design 2-41
212 Rigid Bodies 2-41
213 Scope Editor 2-42
214 Static Analysis 2-45
215 Steel Design 2-46
216 Steel Tables 2-48
217 Utility Programs 2-48
- iv -
CHAPTER 3 ERROR CORRECTIONS
31 Dynamic Analysis 3-132 Finite Elements 3-233 General 3-234 GTMenu 3-335 Model Wizard 3-436 Nonlinear Analysis 3-437 Offshore 3-538 Reinforced Concrete Design 3-539 Static Analysis 3-5310 Steel Design 3-6
CHAPTER 4 KNOWN DEFICIENCIES
41 Finite Elements 4-142 General InputOutput 4-243 GTMenu 4-344 Rigid Bodies 4-445 Scope Environment 4-4
CHAPTER 5 PRERELEASE FEATURES
51 Introduction 51-152 Design Prerelease Features 52-1
521 LRFD3 Steel Design Code and Parameters 52-1522 GTSTRUDL BS5950 Steel Design Code and Parameters 52-31523 GTSTRUDL Indian Standard Design Code IS800 52-53524 ACI Code 318-99 52-71525 Rectangular and Circular Concrete Cross-Section Tables 51-75526 ASD9-E Code 52-77527 Design of Flat Plates Based on the Results of Finite
Element Analysis (The DESIGN SLAB Command) 52-9353 Analysis Prerelease Features 53-1
531 The CALCULATE ERROR ESTIMATE Command 53-1532 The Viscous Damper Element for Linear and Nonlinear
Dynamic Analysis 53-5
- v -
54 General Prerelease Features 54-1
541 ROTATE LOAD Command 54-1
542 COUTPUT Command 54-5
543 Reference Coordinate System Command 54-7
543-1 Printing Reference Coordinate System Command 54-10
544 Hashing Algorithm to Accelerate Input Processing 54-11
545 GTMenu Point and Line Incidences Commands 54-13
- vi -
This page intentionally left blank
GT STRUDL Introduction
1 - 1
Chapter 1
Introduction
Version 29 covers GTSTRUDL operating on PCrsquos under the Windows XP andWindows 2000 operating systems Chapter 2 presents the new features and enhancementswhich have been added since the Version 28 and Version 281 releases Chapter 3 providesyou with details regarding error corrections that have been made since the Version 28 andVersion 281 releases Chapter 4 describes known problems with Version 29 Chapter 5describes prerelease features -- new features which have been developed and subjected tolimited testing or features for which the user documentation have not been added to theGTSTRUDL User Reference Manual The command formats and functionality of theprerelease features may change before they become supported features based on additionaltesting and feedback from users
The Prerelease features are subdivided into Design Analysis and General categories Thefeatures in these categories and their sections numbers in Chapter 5 are shown below
52 Design Prerelease Features
521 LRFD3 Steel Design Code and Parameters
522 BS5950 Steel Design Code and Parameters
523 Steel Design by Indian Standard Code IS800
524 ACI Code 318-99
525 Rectangular and Circular Concrete Cross Section Tables
526 ASD9-E Code
527 Design of Flat Plates Based on the Results of Finite Element Analysis(The DESIGN SLAB Command)
53 Analysis Prerelease Features
531 Calculate Error Estimate Command
532 The Viscous Damper Element for Linear and Nonlinear DynamicAnalysis
Introduction GT STRUDL
1 - 2
54 General Prerelease Features
541 Rotate Load Command
542 Coutput Command
543 Reference Coordinate System Command
544 Hashing Algorithm to Accelerate Input Processing
545 GTMenu Point coordinates and Line Incidences Commands
We encourage you to experiment with these prerelease features and provide us withsuggestions to improve these features as well as other GTSTRUDL capabilities
Note that GTMenu is described in Volume 2 of the Version 29 Release Guide TheGTMenu Release Guide is available under Help in the GTSTRUDL Output Window (Help -Reference Documentation - GTMenu)
GT STRUDL New Features
2 - 1
Chapter 2
New Features in Version 29
This chapter provides you with details regarding new features and enhancements thathave been added to many of the functional areas of GTSTRUDL in Version 29 This releaseguide is also available online upon execution of GTSTRUDL under Help - ReferenceDocumentation -GT STRUDL Release Guide
21 Data Base Exchange (DBX)
1 A SUPPORTS ONLY option has been added the WRITE JOINT RESULTScommand If SUPPORTS ONLY is specified joints in the given list that have notbeen specified as supports will be ignored and not included in the generated file Thiswill make it easier to export results for foundation design The syntax of the revisedcommand is shown below
WRITE JOINT RESULTS ( SUPPORTS (ONLY) ) JOINTS list
This options is described in Volume 5 of the GTSTRUDL User Reference Manualon page Summary 2-4
22 Dynamics
1 A new eigenvalue analysis procedure designated as GTSELANCZOS has beenimplemented The GTSELANCZOS method includes numerous modifications tocomputer RAM virtual memory and hard drive management operations that haveresulted in eigenvalue analysis time-to-solve efficiency improvements for all modelsand in particular time-to-solve improvements of between 50 and 100 times formodels exceeding 30000 degrees of freedom The GTSELANCZOS method isspecified in the EIGENPROBLEM PARAMETERS as shown in the example below
EIGENPROBLEM PARAMETERSNUMBER OF MODES 15SOLVE USING GTSELANCZOSEND
New Features GT STRUDL
2 - 2
2 Variable support motion loads are now supported by transient physical analysis asperformed by the DYNAMIC ANALYSIS PHYSICAL and PERFORM PHYSICALANALYSIS commands You may now specify different time histories at differentjoints
The STORE TIME HISTORY command has been extended as follows in order toprovide for the specification and storage of VELOCITY and DISPLACEMENT timehistories in addition to ACCELERATION time histories
STORE TIME (HISTORY) (
FORCEACCELERATIONVELOCITY
DISPLACEMENT
TRANSLATION ROTATION
)
name (FACTOR s)
⎧
⎨⎪⎪
⎩⎪⎪
⎫
⎬⎪⎪
⎭⎪⎪
⎧⎨⎩
⎫⎬⎭
rarrminus
v1 t1 v2 t2 vn tn
A new category of loading has been implemented as part of the TRANSIENTLOADING command as follows
JOINTS
NODESlist
DISPLACEMENT
VELOCITY
ACCELERATION
TRANSLATION
ROTATION
X
Y
Z
file specs
function specs
(START (TIME) v )
where
file specs FILE filnam ([FACTOR] v )
function specsSINE
COSINE[AMPLITUDE] v [FREQUENCY] v ([PHASE] v )
5
1
2 3 4
⎧⎨⎩
⎫⎬⎭
⎧
⎨⎪
⎩⎪
⎫
⎬⎪
⎭⎪
⎧⎨⎩
⎫⎬⎭
⎧
⎨⎪
⎩⎪
⎫
⎬⎪
⎭⎪
⎧⎨⎩
⎫⎬⎭
⎧⎨⎩
⎫⎬⎭
minus
=
=
GT STRUDL New Features
2 - 3
This command is used to specify DISPLACEMENT VELOCITY andACCELERATION joint motion time history data for fully fixed degrees of freedomand is described in Section 2441 of Volume 3 of the GTSTRUDL ReferenceM a n u a l A n e x a m p l e o f t h e u s e o f t h e J O I N TDISPLACEMENTVELOCITYACCELERATION command in the TRANSIENTLOADING command follows
UNITS CYCLES
TRANSIENT LOADING 1
JOINT 1 DISPL TRANSL Y FILE DSIN30
JOINT 1 ACCEL TRANSL Y FUNCT SINE 100E0 -
FREQ 10 PHASE 025 START TIME 01
INTEGRATE FROM 00 TO 10 AT 001
END TRANSIENT LOADING
3 The external results file system for response spectrum and transient dynamicanalyses has been enhanced so that the amount of results data that can be stored andaccessed is now limited only by the amount of unused hard drive disk space Inprevious versions each class of results data was limited in size to two gigabytes
4 The PRINT DYNAMIC FILE command has been extended with the addition of anew NUMBER OF POINTS PER LINE option an example of which is shownbelow
PRINT DYNAMIC FILE lsquoMyRSFilersquo NUMBER OF POINTS PER LINE 1
The NUMBER OF POINTS PER LINE option provides for the specification of thenumber of data points to enter on each line of the resulting report that lists the datapoints contained in the specified response spectrum or time history data file thedefault being four The NUMBER OF POINTS PER LINE may be specified as 12 3 or 4 where for any value other than these the default value of 4 is assumed
New Features GT STRUDL
2 - 4
An example of a response spectrum file report when NUMBER OF POINTS PERLINE 1 is specified as shown below
21 gt PRINT DYNAMIC FILE MyRSFile NUMBER OF POINTS PER LINE 1
PROBLEM DATA FROM INTERNAL STORAGE
JOB ID - NONE JOB TITLE - GTSTRUDL 29 ACTIVE UNITS - LENGTH WEIGHT ANGLE TEMPERATURE TIME FEET KIP CYC DEGF SEC
------------------------------------------------------------------------------
RESPONSE SPECTRA FILE HORIZONT TYPE SPECTRAL ACCEL (LIN) VS FREQUENCY (LIN) ------------------------------------------------------------------------------
DAMPING RESPONSE FREQUENCY RESPONSE FREQUENCY RESPONSE
70 0772800 010000 0869400 011100 0966000 012500 112700 014300 128800 016700 154560 020000 238280 030000 108514 060000 148120 19020 148120 10000
90 0386400 010000 0434700 011100 0483000 012500 0563500 014300 0644000 016700 0772800 020000 119140 030000 542570 060000 740600 19020 740600 10000
5 Response spectrum analysis now checks the frequencyperiod bounds of responsespectrum curves and issues a warning message if a structural frequency is found tolie outside the bounds of any of the response spectrum curves for the active responsespectrum loads
GT STRUDL New Features
2 - 5
6 The volume of warning messages pertaining to missing results reported by theCREATE PSEUDO STATIC LOAD command has been greatly reduced
7 The Form Static Form UBC97 Static and Form IS1893 Static Load commands havebeen brought to release status These features were prerelease features in previousversions They are now documented in Section 2492 2493 and 2494respectively in Volume 3 of the GTSTRUDL Reference Manual
8 The List Response Spectrum Base and Story Shear capability has been brought torelease status This feature was a prerelease feature in previous versions and isdocumented in Section 2467 of Volume 3 of the GTSTRUDL Reference Manual
9 Another new eigenvalue analysis procedure designated as GTHCLANCZOS hasalso been implemented The GTHCLANCZOS method is a modified form of theGTLANCZOS method in which the Lanczos tridiagonalization of the stiffness anddynamic matrices is performed on matrix hypercolumn blocks consisting of acommand-specified number of matrix elements By default the number ofhypercolumn matrix elements is taken as 10000000 The GTHCLANCZOS methodis most useful when an eigenvalue analysis is to be performed on a model havinggreater than 60000 degrees of freedom (10000 six-degree-of-freedom joints) to befollowed later by a transient analysis andor a response spectrum analysis TheGTHCLANCZOS method is specified in the EIGENPROBLEM PARAMETERScommands (Note This feature was added to Version 281 and is included here sincenot all users have installed Version 281)
23 Elastic Buckling
1 Space truss members may now be used in an elastic buckling analysis Previouslyonly space frame members and plate elements were allowed
2 Space frame members may now have member releases including elastic connectionswhen performing a buckling analysis
New Features GT STRUDL
2 - 6
24 General
1 The output for PRINT GROUP has been changed to include quotes (lsquo) around non-integer names and continuation symbols (-) for multi-line lists This makes it easyto copy-and-paste from the output into a new command
Old format
JOINT NAMES 99999 A1002 A1003 A1004 A1005 A1006 A1007 A1008 A1009 A1010
New format
JOINT NAMES 99999 A1002 A1003 A1004 A1005 A1006 A1007 - A1008 A1009 A1010
The revised PRINT GROUP Command is documented in Section 21223 ofVolume 1 of the GTSTRUDL Reference Manual
2 The EXISTING option for member-types which includes members finite elementsnonlinear springs cables rigid bodies and superelements has been improved to addthe optional subtype filter MEMBERS ELEMENTS NLS or CABLES ONLY Thiswill restrict the generated list to that subtype only which is helpful when the varioussubtypes are mixed in the naming scheme The syntax of the command is shownbelow
EXISTING
MEMBERS
ELEMENTS
NLS
CABLES
ONLY )
ACTIVE
INACTIVE
ACTIVE AND INACTIVE
(list2
)
(BUT list3
) (PLUS list4
)
( ( )
⎧
⎨⎪⎪
⎩⎪⎪
⎫
⎬⎪⎪
⎭⎪⎪
⎧
⎨⎪
⎩⎪
⎫
⎬⎪
⎭⎪
rarr
minus
GT STRUDL New Features
2 - 7
An example of the usage of the command is shown below
PRINT MEM PROP MEMBERS EXISTING MEMBERS ONLY 1 TO 100
The list will contain all members in the range 1 to 100 but exclude any finiteelements nonlinear springs cables rigid bodies or superelements The use ofldquoONLYrdquo is optional
The modified EXISTING list option is described in Section 2122 of Volume 1 ofthe GTSTRUDL Reference Manual
3 The CALCULATE SOIL SPRINGS command now allows a joint to be released inthe direction of a nonlinear spring (COMPRESSION ONLY option) Previously awarning message would be generated and the CALCULATE SOIL SPRINGcommand would not be processed
4 The CALCULATE MEMBER ORIENTATION command has been added to allowyou to automatically generate a BETA angle by specifying the orientation of amembers local XY or XZ plane The syntax of the command is shown below
where
v1 v2 v3 are the global X Y and Z coordinates of the orientation vector Anyvalue not given is assumed to be 00
list is a list of members to be oriented based on the given vector Finiteelements cables nonlinear springs or superelements included in thelist will be excluded without a warning message
AXIS Specify whether the orientation vector locates the local XY plane orthe local XZ plane When AXIS is not specified Y is assumed
YZ
X Y Z
CALCULATE MEMBER ORIENTATION (AXIS )
(FROM) (VECTOR) [ ] v [ ] v [ ] v MEMBER list1 2 3
rarrminus
New Features GT STRUDL
2 - 8
The CALCULATE MEMBER ORIENTATION command is used to calculate aBETA angle for a list of members The calculated BETA angle will rotate themember so that the orientation vector will lie in the memberrsquos local XY or XZ planedepending on which axis was specified
The CALCULATE MEMBER ORIENTATION command is documented in Section21105 of Volume 1 of the GTSTRUDL Reference Manual
5 The GENERATE LOAD command in the MOVING LOAD GENERATOR has threenew options and the format of the output has been changed The revisedGENERATE LOAD command is shown below
where the new options are
MOMENT ARM
The MOMENT ARM option allows you specify a torsional moment (moment X) tobe applied along with the concentrated load to account for moving loads that areapplied eccentric to the centerline of the member v2 is the length of the momentarm in the current length units The value of the applied torsional moment is equalto FYv1v2 where FY is the concentrated force v1 is the scale factor and v2 isspecified moment arm length MOMENT ARM does not apply to LANE LOADS
GENERATE (LOAD)
X
Y
Z
([SCALE] v1) (MOMENT (X) (ARM) v2rarr minus
⎧
⎨⎪
⎩⎪
⎫
⎬⎪
⎭⎪
)
( (INITIAL)i1 a1
)PRINT ON
PRINT OFF
⎧⎨⎩
⎫⎬⎭
⎧⎨⎩
⎫⎬⎭
rarrminus
( CREATE (GROUP) i2a2 ( title ) )
⎧⎨⎪
⎩⎪
⎫⎬⎪
⎭⎪
GT STRUDL New Features
2 - 9
INITIAL a1
The INITIAL option now accepts alpha names You may specify a prefix only(ML) or a prefix and a starting integer (ML101) If the specified sequence ofloading names is not honored due to a conflict with a pre-existing load name amessage will be printed This warning message will also be printed if an integersequence is interrupted
CREATE GROUP
The CREATE GROUP option will create a group from the generated loads This isuseful for including the moving loads in a CREATE AUTOMATIC LOADCOMBINATIONS command The group name may be either integer or alpha-numeric A group title is optional and if specified is limited to 64 characters
The Output from the command has also been changed If PRINT ON is specified(the default) the printed output is now fully compatible with the LOADINGcommand This allows you to copy the output edit and then use the changed outputas loading commands in a subsequent GTSTRUDL job
The MOVING LOAD GENERATOR is documented in Section 211135 ofVolume 1 of the GTSTRUDL Reference Manual
6 When the PRINT MEMBER PROPERTIES command is specified for members withPipe cross-sections from the Table database the OD ID and TH-PIPE of the pipecross-section are now printed as shown below
OD = outside diameter
ID = inside diameter
TH-PIPE = thickness
45 gt PRINT MEMBER PROPERTIES1 PROBLEM DATA FROM INTERNAL STORAGE
JOB ID - FR322 JOB TITLE - Ex1 Check PRINT MEMBER PROPERTIES for Pipe cross-section from T
ACTIVE UNITS - LENGTH WEIGHT ANGLE TEMPERATURE TIME INCH KIP RAD DEGF SEC
MEMBER PROPERTIES-------------------------------------------------------------------------------------------------------- MEMBERSEG TYPE AX AY AZ IX IY IZ SY SZ YD ZD YC ZC EY EZ ID OD TH-PIPE SC
New Features GT STRUDL
2 - 10
f f f fmin a by2
bz2= minus +
f f f fmax a by2
bz2= + +
1 TABLE RoundHSS 12100 6082 6082 208000 104000 104000 23800 23800 HSS8750x0500 8750 8750 4375 4375 0000 0000 7820 8750 0465 0000
2 TABLE RoundHSS 12100 6082 6082 208000 104000 104000 23800 23800 HSS8750x0500 8750 8750 4375 4375 0000 0000 7820 8750 0465 0000
3 TABLE RoundHSS 5720 2881 2881 39000 19500 19500 7020 7020 HSS5563x0375 5563 5563 2782 2782 0000 0000 4865 5563 0349 0000
4 TABLE RoundHSS 5720 2881 2881 39000 19500 19500 7020 7020 HSS5563x0375 5563 5563 2782 2782 0000 0000 4865 5563 0349 0000
5 TABLE WSHAPES9 13200 4040 6168 1310 50000 350000 12400 58100 W12x45 12060 8045 6030 4022 0000 0000 6 TABLE WSHAPES9 13200 4040 6168 1310 50000 350000 12400 58100 W12x45 12060 8045 6030 4022 0000 0000 7 TABLE RoundHSS 8060 4033 4033 245000 122000 122000 21800 21800 HSS11250x0250 11250 11250 5625 5625 0000 0000 10784 11250 0233 0000
8 TABLE RoundHSS 8060 4033 4033 245000 122000 122000 21800 21800 HSS11250x0250 11250 11250 5625 5625 0000 0000 10784 11250 0233 0000
END OF DATA FROM INTERNAL STORAGE
7 The LIST SECTION STRESS command has been modified to print the maximumand minimum combined normal stresses based on the square root of sum of thesquares computation for the pipe and solid round bar cross-sections as shown below
8 Section stresses now can be output for unsymmetrical cross-sections When theUNSYMMETRIC option of the LIST SECTION command is specified the sectionstresses are computed and printed for the positive and negative axes sides of thecross-section See Section 21146 of Volume 1 of the GTSTRUDL Referencemanual for further information
9 A new REFORM command option has been added to the FROM LOAD commandto recreate the form loads based on the original specifications given by the user Thisoption is very useful when a self weight loading (ie load specified by the SELFWEIGHT command) is used in the FORM LOAD command or an independentloading included in the FORM LOAD command has been changed The new FORMLOAD REFORM command will recreate the form load using the original
GT STRUDL New Features
2 - 11
specifications When FORM LOAD commands have been specified the userspecified loads and the load factors are now stored in the database When the FORMLOAD REFORM command is specified the active form loads are then recreatedbased on the userrsquos original specs The new REFORM option also has been addedto the STIFFNESS ANALYSIS and NONLINEAR ANALYSIS commands Thenew REFORM command structure is documented in the following sections
1 FORM LOAD REFORM command Section 2111321 of Volume 1
2 STIFFNESS ANALYSIS REFORM command Section 21132 of Volume 1
3 NONLINEAR ANALYSIS REFORM command Section 2543 of Volume 3
The advantages of the new REFORM option are as follows
A When a self weight which has been specified by the SELF WEIGHT commandor when an independent load used in the FORM LOAD command had beenmodified the REFORM option can be used to recreate the form load againPreviously you had to delete the form loads and respecify the form loads again
B FORM LOADs can be graphically viewed on the structure in the GTMenu attheir combined and factored state while LOAD COMBINATIONS cannot beviewed graphically
C PRINT LOAD DATA shows the combined and factored state of the FORMLOAD commands and also shows the user specified loads and the load factorsused to create the form loads
D Since NONLINEAR ANALYSIS requires a FORM LOAD command usingnonlinear analysis for steel design is now much easer
E The new REFORM option gives the FORM LOAD command the power of beinga load combination and an independent load at a same time
10 A new CONVERT LOAD COMBINATIONS TO FORM LOADS command hasbeen implemented to change user specified load combinations to form loads Thisis often desired when a user intends to perform a nonlinear analysis or would like toview the combined factored load state graphically This command also has an optionto allow FORM LOADS to be converted to LOAD COMBINATIONS Thiscommand has been documented in the Section 2111322 of Volume 1 of theGTSTRUDL Reference manual
New Features GT STRUDL
2 - 12
11 The LIST SUM FORCES command has been brought to release status Thiscommand is used to perform a computation of resultant forces along a cut defined byjoints which may contain members and elements The LIST SUM FORCEScommand is documented in Section 2374 of Volume 3 of the GTSTRUDLReference manual
12 The RUN command has been brought to release status and is now documented inSection 211217 of Volume 1 of the GTSTRUDL Reference manual In additionthe HIDE option has been added allowing you to prevent the appearance of the blackWindows command window when batch (bat or cmd) or console programs are run
13 The ALIGN command has been brought to release status and is now documented inSection 211216 of Volume 1 of the GTSTRUDL Reference manual Thiscommand is useful for aligning members which are almost vertical so that theyconform to the ldquoSpecial Caserdquo of the Beta angle
14 The DELETE JOINTS WITHOUT JOINT COORDINATES command has beenbrought to release status and is documented in Section 2137 of Volume 1 of theGTSTRUDL Reference manual
15 AREA LOAD error checking for illegal member configurations has been improvedAn illegal member configuration is one where the areas to be loaded are not simplybounded For example X bracing should not be included in an AREA LOADrequest but declared INACTIVE before the AREA LOAD command In additionmore modeling errors including overlapping members (where some or all of twomembers centroidal axes are co-incident) are detected and reported (Note Thisfeature was added to Version 281 and is included here since not all users haveinstalled Version 281)
GT STRUDL New Features
2 - 13
25 GTMenu
1 The fonts color and button sizes used in GTMenu have been changed to be moreconsistent with those used in the main GTStrudl Output Window An example of therevised GTMenu Desktop is shown below
2 The Button Bar has been revised to include new Display Load Display Model andAnnotate Model buttons in order to make these features more accessible Anexample of the new Button Bar is shown below
New Features GT STRUDL
2 - 14
The new Display Load and Display Model buttons will bring up the Display Loadand Display Model dialogs which were available in previous versions only byselecting Display on the Menu Bar and then selecting either Loads or Model fromthe pulldown
The addition of these new buttons to the Button Bar makes these highly used featuresmore accessible The new Annotate Model button will bring up the dialog to labeldimensions and coordinates and joint element and member names as well asplacing comments in the Graphical Display Area In previous versions this featurewas available only by selecting the Label button and then selecting DimensionsCoordinates etc from the pulldown
The Label Settings button will bring up the revised Label Settings dialog shownbelow
GT STRUDL New Features
2 - 15
This dialog has new options which allow you to ldquoLabel Structural Attributesrdquo asshown below
If the Support Status on Screen Independent Active Load or Member Release boxesare checked that information will be displayed in the Graphical Display Areapermanently That is each time the Graphical Display area is redrawn informationindicated by the check boxes shown above will also be displayed in the GraphicsWindow You may also have the support legend information displayed in a List BoxThis feature is particularly useful when you have a large number of different supportconditions such as you might have when you have an elastic foundation
3 The revised Display Model dialog now allows you to display additional modelinformation In particular you may now have member lengths KY and KZ factorsand the effective lengths LY and LZ displayed in the Graphical Display Area Therevised Display Model dialog is shown below
New Features GT STRUDL
2 - 16
An example of a structure with the lengths and KZ values labeled is shown below
In the above figure the member lengths as well as the member section names and themember numbers are labeled and rotated so that they are aligned with the membersMember releases are also rotated so they are aligned with the member This featurewas requested by a number of our users at the June 2006 GTSTRUDL Users Groupmeeting
GT STRUDL New Features
2 - 17
4 The Edit pulldown from the Menu Bar now includes options which will allow youto Move or Extrude all or portions of a model The revised Edit pulldown is shownbelow
5 The new Move Model option allows you to move the model based on the distancebetween two joints or by incrementing the coordinates The Move Model dialog isshown below
New Features GT STRUDL
2 - 18
6 Another new option has been added to the Edit pulldown which will allow you toextrude a model You may extrude a planar truss or frame model to create additionalplanes and you may have members connecting the various planes You may alsoextrude one dimensional members into 2D finite elements This option is usefulwhen you want to extrude a member in a floor plane vertically but you want to haveit model a shearwall in a building The third option allows you to extrude a 2D finiteelement mesh into a mesh of 3D solids You may specify uniform or variablespacing when extruding a model using any of these options
An example of the new Extrude Model dialog is shown below
GT STRUDL New Features
2 - 19
An example illustrating the use of the Extrude Selected Joints to ConnectingMembers option is shown below
A two dimensional frame is shown above The model was extruded by selecting allof the joints except the joints on the bottom of the frame The result after extrusionis shown below
New Features GT STRUDL
2 - 20
An example illustrating the use of the Extruding 2D finite elements to 3D (solid)finite elements is shown
The two dimensional finite element model is shown above The model produced byextruding the above model to a model containing three dimensional solid finiteelements is shown below
GT STRUDL New Features
2 - 21
7 The Copy Model option under the Edit pulldown now has an option which will allowyou to create a Mirror Image of all or a portion of your model The revised CopyModel dialog and the Specify Mirror Plane dialogs are shown below
The Maintain incidence order check box in the Specify Mirror Plane dialog abovewill maintain the same incidence order for the newly created elements as the originalelements so all elements will have the same incidence order
New Features GT STRUDL
2 - 22
An example of a two dimensional finite element model before and after using thenew Mirror Image option is shown below
GT STRUDL New Features
2 - 23
8 The efficiency of rotating large finite element models using the cursor has beengreatly improved Now only the boundary lines are drawn as the structure isrotating The wire frame of the model is drawn when the cursor is released Anexample showing a solid model and the boundary outline which appears when themodel is rotated are shown below
New Features GT STRUDL
2 - 24
9 The following information is now written to the Windows Registry Thisinformation will now be retained between executions of GTSTRUDL and you willnot need to respecify the information
Display Label Settings - display and labeling of points curves jointsmembersetc
Default Settings - color font and display options
Color Map
Redraw Solid options
Set Arrow Key increments
10 An option to reset all of the above items to their original settings except for theDisplay Label Settings has been added to the Set Display Options (Options - DefaultSettings - Display Options) dialog as shown below
GT STRUDL New Features
2 - 25
11 Punching Shear results are now available for display under the Results pulldown asshown below
The new Punching Shear dialog is shown below
New Features GT STRUDL
2 - 26
12 A check box has been added to the Results - Diagrams and Envelopes dialog whichwill allow you to automatically label the maximum and minimum values on diagramsand envelopes This feature will minimize the time required by users to label thesevalues and their locations The modified Member Forces dialog is shown below withthe box checked to ldquoLabel Max and Minrdquo
An example of a structure with the maximum and minimum values automaticallylabeled is shown on the following page
GT STRUDL New Features
2 - 27
New Features GT STRUDL
2 - 28
13 The Redraw Solid function in GTMenu will now draw members with variableproperties and use the length of the segments to draw the members with variableproperties This feature is particularly useful in offshore structures where memberswith variable diameter pipes are often used An example of an offshore structurewith variable properties is shown below
14 Redraw Solid will now draw I-GIRDER and PLATE GIRDER prismatic andvariable member cross sections which were specified in the Member Propertiescommand
15 For models which contain 3D solid finite elements Redraw Solid will now draw thesolid display much faster as only the exterior faces of the solid will be drawn Thiswill also improve the efficiency of the Scope Editor and Printing of the display fromRedraw Solid as a fewer number of faces must be printed or brought into the ScopeEditor The time to produce contouring results has also been greatly reduced formodels which contain 3D solid finite elements
16 The boundaries of a finite element are now also highlighted when it is selected witha right click of the mouse Previously only an ldquoxrdquo would be drawn at the centroidof the element
GT STRUDL New Features
2 - 29
17 A joint member or element may now be ldquodeselectedrdquo by selecting it again in ldquoHitrdquomode When an item is initially selected a red ldquoxrdquo is drawn Now when the itemis selected again (deselected) the red ldquoxrdquo is replaced with an ldquoxrdquo drawn in the samecolor as the Global Coordinate Axes
18 The Moving Load dialog has been modified to make the Diagram option visiblewhen the dialog is opened
19 The Graphics Window is now active upon entering GTMenu This enables the userto use the HotKeys immediately without requiring a mouse click in the GraphicsWindow to activate it
20 Additional cylindrical coordinate systems are now available in GTMenu Previouslyonly a cylindrical coordinate system about the Y axis was available NowldquoCylindrical Xrdquo and ldquoCylindrical Zrdquo coordinate systems are available under theCoordinate System pulldown from the Menu Bar as shown below
21 A joint may now be used to specify the location of a plane parallel to a global planewhen selecting a domain Previously the user could enter only a coordinate valueto specify this location The revised Global Plane dialog is shown below
New Features GT STRUDL
2 - 30
22 The model is no longer redrawn when selecting a filename or when entering theView menu
23 The ldquoirdquo hotkey now produces an isometric display
24 When creating a joint at a line intersection when the endpoints of the line are pointsthe user is now prompted to enter ldquoPointsrdquo
25 A right click in the Graphics Window now lists up to 20 duplicates (joints memberselements) which exist at the same location in the Inquire Output window
26 When splitting a member using the Variable option the cursor is now automaticallypositioned in the Number of Members input box
27 When labeling reactions using the ldquoAllrdquo mode the labeling is now confined to jointsin the current window
28 The output of large numbers will automatically be converted to an exponentialformat rather than trying to use a fixed format which may result in an overflow
29 The box indicating the currently active independent load on the Button Bar now hasthe title ldquoIndependent Loadrdquo
30 When creating three-dimensional solid elements the text input box for an elementrsquosthickness is now omitted
31 The structure is now immediately redrawn when the Z-up checkbox is selected in theView dialog
32 The screen layout has been adjusted to accommodate widescreen displays
33 Abbreviations have been eliminated in the output from the Check Model dialog
GT STRUDL New Features
2 - 31
34 The Check Model output now includes a summary of information such as themaximum and minimum element aspect ratios and the maximum and minimummember volumes as well as the element or members associated with the maximumand minimum values An example of the Member Volume Ratio summary outputis shown below
35 The current active units are now output at the top of the output from Check Modelas also shown in the above figure
36 A right mouse click will now interrupt output from Check Model after outputting upto 500 lines of output This is particularly useful if the user selected output ofinformation such as the member volume or element aspect ratios for large modelswithout realizing the amount of output that could result Also clicking on the Cancelbutton will also interrupt the Check Model output
37 The number of members or elements now appears in the prompts when a user hasrequested the member volume or slenderness ratios or the element aspect ratios to beoutput from the Check Model dialog
New Features GT STRUDL
2 - 32
38 Large numbers are now automatically output in an exponential format whenperforming a Check Model These large numbers often occur when the structuralweight or load summation information was output
39 When members with variable properties are selected by right clicking in the GraphicsWindow the Inquire Output window now shows the Property Groups and segmentlengths for each segment of the variable member as shown below
40 Member loads may now be input and displayed in the currently active coordinatesystem
41 If a Local member load is displayed as Global components and then one of the globalcomponents is edited the complete local member load is reformed when the load issubsequently stored
42 The default increments for Zoom and Pan have been changed to 002 and the defaultincrement for Rotate has been changed to 20
43 Steel Parameter information has been compressed when using Generate Input File
44 Information related to loads created using a Form Load command is now stored inGTMenu and retained when entering or exiting GTMenu A GTMenu GeneratedInput File now contains Form Load commands
45 When editing IDrsquos of joints members or elements the tab or arrow keys may nowbe used to move the cursor between names in the ID list
GT STRUDL New Features
2 - 33
26 GT STRUDL Output Window
1 A new option has been added to the File menu - Launch Windows Explorer
This pick will open a new Windows Explorer starting in your Working DirectoryThis allows you to browse your computer to find or move files easily
2 The File - Save menu selection has been expanded as shown below
Three new options have been added to the above pulldown
Text Input File
This option is the same as the ldquoCreate a NEW text input filerdquo in the File menu andhas been added here for user convenience An input file based on the currentGTSTRUDL data base will be created Note that this input file is not a copy of theinput file (if any) used to create the current data base and any comments that existedwill not appear in the new input file This input file is the same as if you were inGTMenu and selected the File - Generate GT STRUDL text input option
New Features GT STRUDL
2 - 34
Text Input File plus Command History
An input file based on the current GTSTRUDL data base will be created and thecurrent Command History will be appended The Command History is commandsyou have typed or created using dialogs in the current GTSTRUDL session Thisoption is useful to easily add analysis and design commands you have createdRemember to review the created file before you use it in a subsequent GTSTRUDLsession
Text Input File plus Command History and Edit
This option is the same as above plus the created input file is opened in WindowsNotepad to review and edit
3 The Analysis pulldown has been modified and you can now launch the new staticanalysis equation solvers GTSES and GTHCS as shown below
More information on the GTSES and GTHCS equations solvers may be found inSection 214
GT STRUDL New Features
2 - 35
4 The Analysis problems found option in the Analysis pulldown has also beenextended to include the GTSES solver when selecting ldquoInstabilities found ldquo in thepulldown shown below
5 The Dynamic Analysis Eigenvalue dialog now has an option to use the newGTSELanczos eigensolver as shown below
Further information on the GTSELanczos eigensolver may be found in Section 22In addition the Nonlinear Dynamic Analysis dialog now has an option to ldquoUse theSparse Equation Solverrdquo
New Features GT STRUDL
2 - 36
6 The Results datasheets now have an option which allows you to changes units in thedatasheets as noted below
7 Harmonic results versus frequency may now be displayed as shown in the followingdialogs and plot
GT STRUDL New Features
2 - 37
8 The Steel Design Wizard has a new Advanced button which will display the variousoptions
New Features GT STRUDL
2 - 38
27 Model Wizard
1 A lsquoTangentrdquo option has been added to the the Tank Wizard to allow for a smoothtransition from the circular to hemispherical portions of the tank as shown below
2 Compression Only and In-Plane springs have been added to the Rectangular TankWizard
28 Nonlinear Analysis
1 The new Commands DEFINE PLASTIC HINGE CROSS SECTION DELETEPLASTIC HINGE CROSS SECTION and PRINT PLASTIC HINGE CROSSSECTION have been implemented These new commands can be used to definegeneral customized plastic hinge cross section data structures that can be used todefine the fiber geometry and material properties for plastic hinges or plasticsegments at the start and end of members These new commands are described inSection 2522 of Volume 3 of the GTSTRUDL Reference Manual
2 A new BASE ISOLATION ELEMENT DATA command has been implemented forthe purpose of defining a new class of two-node global base isolation elementsincluding at this time a sliding friction bearing element where the slidingbearingsurface is flat and a friction pendulum element where the slidingbearing surface is
GT STRUDL New Features
2 - 39
assumed to be concave and spherical The element supports both a constant frictionmodel and a variable friction model in which the instantaneous coefficient of frictionis a function of slider velocity and bearing pressure The base isolation elements areapplicable for both nonlinear static and dynamic analyses The BASE ISOLATIONELEMENT DATA command is described in Section 2533 of Volume 3 of theGTSTRUDL Reference Manual
29 Nonlinear Dynamic Analysis
1 Nonlinear dynamic analysis has been brought to a release status In previousversions of GTSTRUDL nonlinear dynamic analysis was a prerelease feature TheDYNAMIC ANALYSIS NONLINEAR command is described in Section 24102of Volume 3 of the GTSTRUDL Reference Manual
2 The GTSES option has been added to the DYNAMIC ANALYSIS NONLINEARcommand an example of which is shown below
DYNAMIC ANALYSIS NONLINEAR GTSES NEWMARK BETA 025
The GTSES options provides for the selection of an alternate equation solver thattakes maximum advantage of the sparsity of the the assembled stiffness mass anddamping matrices for the solution of the nonlinear equations of motion Comparedto the standard default equation solver larger models can be handled andsignificantly faster solution times can be realized
3 The nonlinear hysteretic spring element NLS4PH has been brought to release statusThis element was a prerelease feature in previous versions and is documented inSection 2532 in Volume 3 of the GTSTRUDL Reference Manual
210 Offshore
1 Several new parameters have been added to the FATIGUE MEMBER commandThe CHORD LENGTH FACTOR parameter provides for the specification of a chordlength factor The actual chord length that is used in the computation of SCF factorsfor a fatigue brace member is now computed by multiplying the length of the chordmember associated with the brace member by the specified CHORD LENGTHFACTOR The CHORD LENGTH FACTOR must be greater than 00 and is takenas 10 by default See Section 531 Volume 8 of the GTSTRUDL ReferenceManual for more information
New Features GT STRUDL
2 - 40
The CHORD FIXITY parameter has been added to the FATIGUE MEMBERcommand The CHORD FIXITY parameter is used for the computation of SCFfactors according to the Efthymiou method The value of the CHORD FIXITYparameter may vary from 05 to 10 and is taken as 07 by default See Section 531of Volume 8 of the GTSTRUDL Reference Manual for more information
2 Offshore punching shear check results are now stored in the database There are nowthree ways to display or output the punching shear check results
A Display the Punching shear results in GTMenu as described in Section 25
B View the results using the datasheet under the SteelDesign pulldown in theGTSTRUDL Output Window
C Print the punching shear results with the LIST PUNCHING SHEAR CHECKRESULTS command (Section 211443 of Volume 1)
3 The FATIGUE MEMBER command has been enhanced to include an option to nowselect the Efthymiou equations to compute stress concentration factors for tubularjoints having T Y K and X classifications Only the Kuang andor Smedleyequations were available in Version 28 and previous versions This is described inSection 531 of Volume 8 of the GTSTRUDL Reference Manual (Note Thisfeature was added to Version 281 and is included here since not all users haveinstalled Version 281)
4 A new and more efficient command has been implemented for fatigue analysis Thenew PERFORM FATIGUE ANALYSIS command can now be used instead of theexisting COMPUTE FATIGUE LIFE command The abbreviated syntax of the newPERFORM FATIGUE ANALYSIS command is shown below
PERFORM FATIGUE (ANALYSIS)PSD
DISCRETE(BASE PERIOD v ) -b
⎧⎨⎩
⎫⎬⎭
(stress information) (deletions) (REPORT (SCF DIAGNOSTICS))
The complete syntax of the PERFORM FATIGUE ANALYSIS command may befound in Section 565 of Volume 8 of the GTSTRUDL Reference Manual
GT STRUDL New Features
2 - 41
The PERFORM FATIGUE ANALYSIS command executes the fatigue lifecomputations on a joint-by-joint basis which dramatically improves the efficiencyof the fatigue analysis computations and increases the size of the fatigue analysis jobthat can be solved (number of fatigue wave loads and number of fatigue members)The PERFORM FATIGUE ANALYSIS command performs all fatigue analysiscomputations including automatic joint classification if requested computation offatigue stresses computation of transfer functions and computation of fatiguedamage and life The PERFORM FATIGUE ANALYSIS command should not beused in conjunction with the split fatigue analysis commands described in Section56 of Volume 8
The REPORT SCF DIAGNOSTICS option causes SCF equation diagnosticinformation and joint classification information to be reported during the fatigueanalysis computations If not given this report which can be quite lengthy issuppressed All other command options are identical to those of the COMPUTEFATIGUE LIFE command described in Section 553 Volume 8 (Note This featurewas added to Version 281 and is included here since not all users have installedVersion 281)
5 For the APILRFD1 code the reduction for FYLD has been removed as it is notneeded for LRFD (Note This feature was added to Version 281 and is includedhere since not all users have installed Version 281)
211 Reinforced Concrete Design
1 A new prerelease feature has been implemented which will design the slabreinforcing steel due to flexure along a cut in a finite element mesh composed ofplate bending or plate elements The DESIGN SLAB REINFORCEMENTcommand is documented in Section 527
212 Rigid Bodies
1 The TYPE RIGID command now includes a new GLOBAL option for the RIGIDPLANE PLATE and PIN joint constraints When this option is given the planarcoordinate systems for these rigid bodies coincides with the global coordinatesystem
New Features GT STRUDL
2 - 42
The important implication of being able to use the GLOBAL option is that SLAVERELEASES and JOINT RELEASES (for master joints that are also supports andhave no other incident members and finite elements) are more easily specified withrespect to the global coordinate system The revised TYPE RIGID command isdescribed in Section 26521 of Volume 3 of the GTSTRUDL Reference Manual
213 Scope Editor
GTSTRUDL 29 includes a new version of the Scope Editor Version 40 You willsee the new version number in the title bar of the Scope Editor In addition a muchhigher resolution for drawing is now being used You will probably not see thehigher resolution on the screen unless you zoom in but printing is greatly improvedThis means that a version 40 Scope Editor document cannot be read with previousversions (32a and earlier) although earlier Scope Editor documents can be openedwith 40 Zooming has been improved so that the ldquozoomed tordquo area will remain inthe view
1 Improved Options
You can now set margins in the Options dialog using the General page (see below)This allows you to restrict the drawing area to be inside an applied templateMargins are specified in 001 inch (025 mm) increments The Options dialog maybe reached from the View - Options menu pick In addition an equivalent dialog isavailable in GTMenu from the File - Page Setup menu pick
GT STRUDL New Features
2 - 43
2 Automatic ldquoDaterdquo ldquoTimerdquo and ldquoPromptrdquo fields in Templates
You can now add automatic date and time stamps and user supplied text data toScope Editor documents when you use a template When you create the ScopeEditor document to used as a template you can add text entries that will be replacedwith the requested data The new text uses the same font and rotation as the originalso you can determine the size color etc of the inserted text
DateCreate a text entry with the characters ldquoltltDaterdquo followed with an optional integer1-7 which correspond the Date tool discussed earlier When the template is appliedto a GTMenu file or new Scope Editor document ldquoltltDaterdquo will be replaced with thecurrent date and the font of the date text will match the font of the ldquoltltDaterdquo entrySee the Tools - Date menu pick for a description of the seven available date formats
TimeCreate a text entry with the characters ldquoltltTimerdquo followed with an optional ldquo12rdquoldquoAMrdquo or ldquoPMrdquo for a 12-hour time or ldquo24rdquo for a 24-hour time When the Templateis applied to a GTMenu file or new Scope Editor document ldquoltltTimerdquo will bereplaced with the current time and the font of the time text will match the font of theldquoltltTimerdquo entry
PromptCreate a text entry with the characters ldquoltltPromptrdquo followed with an optional lsquohintrsquofor the prompt When the template is applied to a GTMenu file or new Scope Editordocument ldquoltltPromptrdquo will be replaced with what you type into the Promptwindow For example the entry ldquoltltPrompt Title of documentrdquo would bring up thisdialog box each time you print from GTMenu whether it is the ldquoPrintrdquo button or theFile - Print Preview and Edit selection
ldquoCancelrdquo will cause the prompt entry to be ignored meaning nothing will be insertedinto the Scope Editor document
New Features GT STRUDL
2 - 44
Examples
If these entries were in your template
They would appear in your document as this
3 Improved Paragraph Tool
The Paragraph tool now maintains the associated text as a single block of textwhereas in previous versions the Paragraph text was separated into individual linesof text This means you can now move change the font or edit the paragraph as ablock after it has been created
GT STRUDL New Features
2 - 45
214 Static Analysis
1 The STIFFNESS ANALYSIS command has been extended as follows
The new option GTSES provides for the selection of a new significantly moreefficient equation solver The large majority of problems that can be solved by thedefault solver can be solved significantly faster by the GTSES solver and manylarge problems that could not be solved previously by the default solver now can besolved very efficiently by the GTSES solver To date the GTSES solver hasdemonstrated a 10 to 50 fold increase in speed for problem sizes up to 350000degrees of freedom
The revised STIFFNESS ANALYSIS command with the new GTSES option andother new options is documented in Volume 1 - Section 21132 of the GTSTRUDLReference Manual
2 The sparse matrix solver has also been extended to the PERFORM NUMERICALINSTABILITY ANALYSIS command using a syntax similar to that of theSTIFFNESS ANALYSIS command
PERFORM NUMERICAL INSTABILITY ANALYSIS GTSES
The revised PERFORM NUMERICAL INSTABILITY command is documented inVolume 1 - Section 211314 of the GTSTRUDL Reference Manual
3 The statistical output from the GTHCS equation solver has been improved to nowoutput information regarding the number of degrees of freedom the number of termsin the skyline and the number of hyper-columns (Note This feature was added toVersion 281 and is included here since not all users have installed Version 281)
NJP i
STIFFNESS (ANALYSIS) WITHOUT REDUCE (BAND)GTSES
⎧ ⎫⎪ ⎪⎨ ⎬⎪ ⎪⎩ ⎭
New Features GT STRUDL
2 - 46
215 Steel Design
1 Three new parameters have been added to CAN97 code The new parameter namesare K U1Y and U1Z These parameter are applicable to the combined axial andbending equations of Clauses 1381(b) 1381(c) 1382(b) and 1382(c) The newparameters are described below
Table CAN97
CAN97 Code Parameters
Parameter Default Name Value Meaning
Combined Stresses
K 10 Effective length factor used in the computation of the Cr inthe Clauses 1381(b) and 1382(b)
U1Y Computed Factor to account for moment gradient and for second-ordereffect of axial force acting on the deformed member Thisparameter is applicable to the combined axial and Y axisbending The default value is computed according to theClause 1383 of the 1997 CISC Seventh Edition
U1Z Computed Factor to account for moment gradient and for second-ordereffect of axial force acting on the deformed member Thisparameter is applicable to the combined axial and Z axisbending The default value is computed according to theClause 1383 of the 1997 CISC Seventh Edition
2 A new parameter called lsquoClass3 has been added to BS5950 and 00BS5950 codesThis parameter allows the user to request that the code check or design to beperformed based on the class 3 classification A user specified value of lsquoYESrsquo forthis parameter indicates that when code check or design is performed for BS5950 or00BS5950 code equations based on the Class 3 classification should be used Thismeans when user specifies a value of lsquoYESrsquo for parameter lsquoClass3 BS5950 or00BS5950 code check will assume that the member is a class 3 cross-section Thedefault value for this parameter is lsquoNOrsquo This indicates that the program computesthe classification of the member based on the cross-section properties
GT STRUDL New Features
2 - 47
3 Two new cross-sections have been added to the LRFD3 code The new cross-sections are Solid Round Bar and Solid Rectangular Bar cross-sections You maycode check or design based on axial and bending effect in these cross-sections TheLRFD3 code check parameters are discussed in the Table LRFD31-1 The LRFD3code is documented in Section 521 of this Release Guide as a prerelease feature
4 Parameter ALSTRINC has been added to the APIWSD20 and AISI89 codesALSTRINC is used to specify the 13 allowable stress increase for wind or seismicloads
5 Steel Deflection Check and Design has been brought to release status and isdocumented in Section 214 of Volume 2A of the GTSTRUDL Reference Manual
Three new parameters have been added to deflection check or design The newparameters set deflection limitations based on the load list The new parameters areldquoDefLimLordquo ldquoDefLimYLrdquo and ldquoDefLimZLrdquo These new parameters are similar tothe existing parameters ldquoDefLimitrdquo ldquoDefLim-Yrdquo and DefLim-Zrdquo except you cannow specify deflection limitations based on the load list rather than member listNote that parameters ldquoDefLimitrdquo ldquoDefLim-Yrdquo and DefLim-Zrdquo are for settingdeflection limitations based on the member list and the parameters ldquoDefLimLordquoldquoDefLimYLrdquo and ldquoDefLimZLrdquo are for setting deflection limitations based on theload list
6 A new warning message has been added to the LRFD codes (ie LRFD3 and LRFD2codes) to indicate that nonlinear analysis is required Load and resistance factordesign (LRFD) codes require nonlinear analysis to account for the second order (P))effects of the frame structures If linear static analysis (elastic analysis stiffnessanalysis) has been used a warning message is issued that nonlinear analysis isrequired for LRFD codes
7 Steel grades for pipe and tube cross-sections have been added to ASD9 and 78AISCcodes Steel grades are listed in the Table 21-3a in Volume 2A of the GTSTRUDLReference Manual
8 A new parameter called lsquoClass3 has been added to EC3 code This parameter allowsthe user to request that the code check or design to be performed based on the class3 classification A user specified value of lsquoYESrsquo for this parameter indicates thatwhen a code check or design is performed for EC3 code equations based on theClass 3 classification should be used When a value of lsquoYESrsquo has been specified forparameter lsquoClass3 EC3 code check will assume that the member is a class 3 cross-
New Features GT STRUDL
2 - 48
section The default value for this parameter is lsquoNOrsquo This indicates that theprogram computes the classification of the member based on the cross-sectionproperties (Note This feature was added to Version 281 and is included here sincenot all users have installed Version 281)
9 The Summarize command for the critical section prints the summary results for thesection that has the highest actualallowable ratio When the KLr actualallowableratio is the highest ratio during a code check or design the Summarize command forthe critical section outputs that sectionrsquos summary results In general prismaticsections have the same KLr ratio for each loading and section Since the KLr valueis the same for all sections when the Summarize command is issued and the KLr isthe highest actualallowable ratio the summary results for the last loading and lastsection are printed In this version of GTSTRUDL the summarize output for thecritical section has been modified to also print the section with the highest stressvalue The section which has the highest stress value also has the highest KLr ratio(Note This feature was added to Version 281 and is included here since not all usershave installed Version 281)
216 Steel Tables
1 European channel (U) profiles from Table ldquoU-Stahlrdquo of the ldquoSTAHLBAU-PROFILES 21 neu bearbeitete und erweiterte Auflage uumlberarbeiteter Nachdruck1997 have been added to GTSTRUDL
217 Utility Programs
1 A new utility program npf2ssc has been added to convert Neutral Plot Files (NPF) intoScope Editor (SSC) files This allows users who generate NPFs with PLOT commandsor through GTSelos to use the Scope Editor to view and print their files
This utility program may be found at the following location after installing Version 29
ltinstallgtUtilitiesnpf2ssc
where ltinstallgt is CProgram FilesGTStrudl by default
Please see the Readme file in the above directory for more information about optionsfor npf2ssc
GT STRUDL Error Corrections
3 - 1
CHAPTER 3
ERROR CORRECTIONS
This chapter describes changes that have been made to GTSTRUDL to correct errors Theseerrors may have produced aborts incorrect results or restricted use of a feature in previous versionsof GTSTRUDL Please note that some error corrections listed below were previously corrected inVersion 281 and noted in the Version 281 Release Guide These error corrections are also notedhere since Version 281 was not installed by all users The error corrections are discussed by the primary feature areas of GTSTRUDL
31 Dynamic Analysis
1 The FORM MISSING MASS command now functions as documented and assumes adamping ratio if the word RATIO or PERCENT is omitted after DAMPING Previously anerror message would be output and a damping ratio of 00 would be assumed This correctionwas previously noted in the Version 281 Release Guide and is also noted here forcompleteness (GPRF 200503)
2 The INERTIA OF JOINTS FROM LOADS command will no longer abort if memberfiniteelement loads are present in any of the loading conditions specified in the command and anyof the membersfinite elements have undefined properties This correction was previouslynoted in the Version 281 Release Guide and is also noted here for completeness (GPRF200505)
3 The CREATE PSEUDO STATIC LOAD command will no longer compute a SSRS pseudostatic load for other than response spectrum modal combination types when two or moreresponse spectrum source loads are specified Incorrect member section forces no longer willbe computed for SSRS pseudo static loads computed from types of dynamic loads other thanresponse spectrum mode combinations (GPRF 200508)
4 Response spectrum mode combination stress and strain results for 2D3D finite elements arenow correct when the external file solver is used for the response spectrum analysis Thisproblem was corrected in Version 281 (GPRF 200613)
Error Corrections GT STRUDL
3 - 2
32 Finite Elements
1 Results will now be computed correctly when global temperature gradients are applied to theBPHQ BPHT SBHQ SBHQ6 SBHT and SBHT6 elements (GPRF 200604)
33 General
1 The FORM LOAD command will now copy member loads on the IPCABLE element to thenew loading condition Previously an error message would be output and member loads onthe IPCABLE element would not be copied to the new loading condition This correction waspreviously noted in the Version 281 Release Guide and is also noted here for completeness(GPRF 200506)
2 An abort will no longer occur if a model containing a self weight loading was saved undera version prior to Version 28 and then is subsequently restored in Version 28 and theSTIFFNESS ANALYSIS command is specified This correction was previously noted in theVersion 281 Release Guide and is also noted here for completeness (GPRF 200507)
3 Users have reported cases where they have encountered the Scan flag being On during an
analysis and after specifying SCAN OFF a subsequent analysis still reported that Scan wasOn This problem has been corrected This correction was previously noted in the Version281 Release Guide and is also noted here for completeness (No GPRF issued)
4 The LIST REACTIONS and LIST SUMMATION REACTIONS commands now producecorrect results when master joints of joint ties constraints are also support joints (GPRF200606)
5 Section force computation will no longer abort for pseudo static loads computed fromresponse spectrum and harmonic loads if the number of modes used to compute the responsespectrum andor harmonic analysis results is greater than the number of modes available atthe time the section force computation is attempted The conditions that cause this abort arenow detected and reported as invalid and inconsistent (GPRF 200607)
6 The specification of rigid bodies as members or finite elements in DELETIONS mode hasbeen made a valid method for deleting a rigid body and its corresponding constraint data Inprevious versions the specification of rigid bodies as members or finite elements inDELETIONS mode caused the deletion of the rigid body name and incidence data but notthe constraint data thus causing errors in subsequent analysis executions (GPRF 200611)
GT STRUDL Error Corrections
3 - 3
34 GTMenu(GPRFrsquos are not issued for GTMenu unless specifically noted below)
1 An input file is now generated correctly when an N-Point line follows a curve specification
2 A Moving Load Diagram animation no longer aborts when the animation is steppedbackwards
3 Contouring will no longer abort after the structure has been modified in GTMenu but beforeanother analysis request has been performed
4 A Beta angle may now be edited by selecting the member to be edited from the InquireOutput dialog Previously the user would enter a new Beta angle but it would not beaccepted
5 An error has been corrected in Redraw Solid for circular members such as pipes round barsand circular concrete members Previously part of the circular member would be omittedfrom the Redraw Solid display
6 Linear member load data in the input file created by GTMenu will no longer have asterisks() for the start (LA) and end (LB) of the linear member loads
7 GTMenu will now contour finite elements results including error estimates for models whichcontain a mixture of finite elements and nonlinear springs In previous versions ofGTSTRUDL contouring would stop when the first nonlinear spring or cable element wasencountered in the list of elements Now contouring will process the complete list ofelements and the nonlinear spring and cable elements will be ignored
8 Joints with springs in some directions and rigid restraints in other directions are no longerignored in the Check Model - Rigid Body Constraints check in GTMenu
9 Rotated releases are now considered correctly in the Check Model - Rigid Body Constraintscheck in GTMenu
10 In some instances triangular member loads would be translated into GTMenu incorrectly andthe resulting load display would indicate that the loads were not on the loaded member Thisoccurred in one instance where the member with the triangular load also had a membertemperature load added after the triangular load This problem has been corrected
Error Corrections GT STRUDL
3 - 4
11 The global coordinate axes are now drawn only once when entering GTMenu
12 The dialog indicating the current loads is now cleared so it will not contain a previous list ora duplicate of the current loads
13 Deleted joints are now ignored when Placing Members with the Split at Intersections optionis selected Previously erroneous members would be created and an abort could occur
14 The display of members with the same eccentricities has been corrected Previously theeccentricities could have been scaled incorrectly when several members had the sameeccentricities
15 Members with the same variable cross section properties but with different segment lengthsare now handled correctly Previously the properties including the segment lengths wereconsidered to be the same resulting in incorrect segment lengths being assigned to some ofthe members upon leaving GTMenu or when creating an input file in GTMenu
35 Model Wizard
1 The new Model Wizard discussed in the Version 28 Release Guide was inadvertently omittedfrom the Version 28 installation The Model Wizard in Version 29 includes the new featuresin Version 28 plus the additional features discussed in Chapter 2 of this Release Guide Thiscorrection was previously noted in the Version 281 Release Guide and is also noted here forcompleteness (No GPRF issued)
2 The cylindrical and rectangular tank options will now create correct element loads when theactive force unit is kilonewtons
36 Nonlinear Analysis
1 Nonlinear analysis or pushover analysis will no longer abort if a calculated plastichingesegment strain exceeds the strain corresponding to the last stress-strain point of a user-specified stress-strain curve for that plastic hingesegment (GPRF 200608)
2 Computation of the section force components My and Mz for nonlinear geometric framemembers has been updated to include the higher order correction for cross section rotationfor the case when non-zero shear center eccentricities are defined for the member properties(GPRF 200610)
3 Cable prestress analysis no longer aborts and executes properly when the CHORD LENGTH
GT STRUDL Error Corrections
3 - 5
parameter is not specified in one or more DEFINE CABLE NETWORK commands and thenumber of nodes vary among the cable elements identified in the DEFINE CABLENETWORK commands (GPRF 200612)
37 Offshore
1 In Version 28 the simplified fatigue analysis for standard fatigue members aborted Thesimplified fatigue analysis should ignore such members and now does so in Version 29 Thiscorrection was previously noted in the Version 281 Release Guide and is also noted here forcompleteness (No GPRF issued)
2 The SELECT command will no longer abort when the APIWSD20 offshore design code isspecified This abort was due to an uninitialized variable and did not always occur inprevious versions This was corrected in Versions 28 and 281 but was omitted from therelease guides for these versions and is noted here for completeness (GPRF 200501)
38 Reinforced Concrete Design
1 When a GIRDER was PROPORTIONED the 2nd and subsequent analysis members in thegirder were possibly rotated 90 or 180 degrees for girders that lay parallel to a global axisThis problem has been corrected (GPRF 200601)
2 A SAVE will not work correctly when MEMBER PROPERTIES were specified using aTABLE section in a reinforced concrete job and the DETAIL command was used (GPRF 200602)
3 The output for the spiral reinforcement designed with the PROPORTION command iscorrect regardless of the active units (GPRF 200605)
39 Static Analysis
1 The GTHCS static analysis solver will now produce correct results for loadings whichcontain JOINT DISPLACEMENTS (GPRF 200603)
Error Corrections GT STRUDL
3 - 6
310 Steel Design
1 Automatic K-factor computations now correctly compute the K-factors when the parameterFRLY or FRLZ has been specified This correction was previously noted in the Version281 Release Guide and is also noted here for completeness (GPRF 200504)
2 The value shown for the section location from the List Code Check Results command andthe Code Check Datasheet for metric codes (ie EC3 BS5950 etc) is now the correctvalue (GPRF 200609)
GT STRUDL Known Deficiencies
4 - 1
CHAPTER 4
KNOWN DEFICIENCIES
This chapter describes known problems or deficiencies in Version 29 Thesedeficiencies have been evaluated and based on our experience they are seldom encounteredor there are workarounds The following sections describe the known problems ordeficiencies by functional area
41 Finite Elements
1 The ELEMENT LOAD command documentation indicates that header informationsuch as type and load specs are allowed If information is given in the header andan attempt is made to override the header information a message is output indicatingan invalid command or incorrect information is stored (GPRF 9006)
2 Incorrect results (displacements stresses reactions frequencies etc) will resultif a RIGIDITY MATRIX is used to specify the material properties for the IPSLIPSQ and TRANS3D elements (GPRF 9309)
3 The CALCULATE RESULTANT command may either abort or print out anerroneous error message for cuts that appear to be parallel to the Planar Y axis(GPRF 9421)
4 If a superelement is given the same name as a member or finite element an abort willoccur in the DEVELOP STATIC PROPERTIES command (GPRF 9508)
5 The curved elements TYPE lsquoSCURVrsquo and lsquoPCURVrsquo will produce incorrect resultsfor tangential member loads (FORCE X) An example of the loading commandwhich will produce this problem is shown below
LOADING 1MEMBER LOADS1 FORCE X UNIFORM W -10
where member (element) 1 is a lsquoSCURVrsquo or lsquoPCURVrsquo element(GPRF 9913)
Known Deficiencies GT STRUDL
4 - 2
42 General InputOutput
1 An infinite loop may occur if a GENERATE MEMBERS or GENERATEELEMENTS command is followed by a REPEAT command with an incorrectformat An example of an incorrect REPEAT command is shown below by theunderlined portion of the REPEAT Command
GENERATE 5 MEM ID 1 INC 1 FROM 1 INC 1 TO 2 INC 1REPEAT 2 TIMES ID 5 FROM 7 INC 1 TO 8 INC 1
Only the increment may be specified on the REPEAT command (GPRF 9322)
2 Rigid body elements can not be deleted or inactivated as conventional finiteelements The specification of rigid body elements as conventional finite elementsin the INACTIVE command or in DELETIONS mode will cause an abort in asubsequent stiffness nonlinear or dynamic analysis (GPRF 9721)
3 The path plus file name on a SAVE or RESTORE is limited to 256 characters If thelimitation is exceeded the path plus file name will be truncated to 256 characters This is a Windows limitation on the file name including the path (No GPRF issued)
4 Object groups created by the DEFINE OBJECT command may not be used in aGROUP LIST as part of a list If the OBJECT group is the last group in the listprocessing will be correct However if individual components follow the OBJECTgroup they will fail Also you can not copy members or joints from the OBJECTgroup into a new group
(GPRF 9926)
5 Numerical precision problems will occur if joint coordinate values are specified inthe JOINT COORDINATES command with more than a total of seven digitsSimilar precision problems will occur for joint coordinate data specified in automaticgeneration commands (GPRF 200016)
6 Internal member results will be incorrect under the following conditions
1 Dynamic analysis is performed (response spectra or time history)
2 Pseudo Static Loadings are created
3 Buckling Analysis is Performed
4 Internal member results are output or used in a subsequent steel design afterthe Buckling Analysis
GT STRUDL Known Deficiencies
4 - 3
In addition the eigenvalues and eigenvectors from the Dynamic Analysis areoverwritten by the eigenvalues and eigenvectors from the Buckling Analysis
We consider this problem to be very rare since we had never encountered a jobwhich contained both a Dynamic Analysis and a Buckling Analysis prior to this errorreport
WorkaroundExecute the Buckling Analysis in a separate run which does not contain adynamic analysis
Alternatively execute the Buckling Analysis before the Dynamic Analysisand output the Buckling results and then perform a Dynamic Analysis TheDynamic Analysis results will then overwrite the buckling multiplier andmode shape which is acceptable since the buckling results have been outputand are not used in any subsequent calculations in GTSTRUDL
(GPRF 200414)
43 GTMenu
1 Gravity loads and Self-Weight loads are generated incorrectly for the TRANS3Delement
Workaround Specify the self-weight using Body Forces under Element LoadsELEMENT LOADS command is described in Section 23541 ofVolume 3 of the GTSTRUDL Reference Manual
(GPRF 9518)
2 The Copy Model feature under Edit in the Menu Bar will generate an incorrectmodel if the model contains the TRANS3D element
Workaround Use the DEFINE OBJECT and COPY OBJECT commands inCommand Mode as described in Section 21671 and 21675 ofVolume 1 of the GTSTRUDL Reference Manual
(GPRF 9521)
4 The Load Summations option available under CHECK MODEL will produceincorrect load summations for line edge and body loads on all finite elements TheLoad Summations are also incorrect for projected loads on finite elements The load
Known Deficiencies GT STRUDL
4 - 4
summations for line and edge loadings should be divided by the thickness of theloaded elements The body force summations should be multiplied by the thicknessof the loaded elements
Workaround You can check the load summation by specifying the LIST SUMREACTIONS command after STIFFNESS ANALYSIS
(No GPRF issued)
5 Projected element loads will be displayed incorrectly when they are created or whenthey are displayed using Display Model 6 Loads
Workaround Verify that the loads are correct in the GTSTRUDL Output Windowusing the PRINT LOAD DATA command or by checking thereactions using LIST SUM REACTIONS
(No GPRF issued)
44 Rigid Bodies
1 Response spectrum analysis may abort if rigid bodies andor joint ties with slavereleases are present in the model (GPRF 9918)
2 Static and dynamic analyses will abort if member releases are specified for rigidbodies (GPRF 200502)
45 Scope Environment
1 OVERLAY DIAGRAM in the Plotter Environment produces diagrams that are muchsmaller relative to the plot size than the Scope environment does This is because thestructure plot is magnified to fill the Plotter graphics area but the height of thediagram is not increased As a work-around use the PLOT FORMAT SCALEcommand to decrease the scale factor which will increase the size of the diagramThe current value is printed with a Scope Environment OVERLAY DIAGRAMThe value printed with a Plotter Environment OVERLAY DIAGRAM is incorrectFor example if a Moment Z diagram is OVERLAYed with a scale factor of 1000on the Scope the command PLOT FORMAT SCALE MOMENT Z 50 would scalea reasonable OVERLAY DIAGRAM for the Plotter(GPRF 9619)
GT STRUDL Prerelease Features
51 - 1
CHAPTER 5
PRERELEASE FEATURES
51 Introduction
This chapter describes new features that have been added to GTSTRUDL but areclassified as prerelease features due to one or more of the following reasons
1 The feature has undergone only limited testing This limited testingproduced satisfactory results However more extensive testing is requiredbefore the feature will be included as a released feature and documented inthe GTSTRUDL User Reference Manual
2 The command formats may change in response to user feedback
3 The functionality of the feature may be enhanced in to response to userfeedback
The Prerelease features in Version 29 are subdivided into Design Analysis and Generalcategories The features in these categories are shown below
52 Design Prerelease Features
521 LRFD3 Steel Design Code and Parameters
522 BS5950 Steel Design Code and Parameters
523 Steel Design by Indian Standard Code IS800
524 ACI Code 318-99
525 Rectangular and Circular Concrete Cross Section Tables
526 ASD9-E Code
527 Design of Flat Plates Based on the Results of Finite ElementAnalysis (The DESIGN SLAB Command)
Prerelease Features GT STRUDL
51 - 2
53 Analysis Prerelease Features
531 Calculate Error Estimate Command
532 The Viscous Damper Element for Linear and NonlinearDynamic Analysis
54 General Prerelease Features
541 Rotate Load Command
542 Coutput Command
543 Reference Coordinate System Command
544 Hashing Algorithm to Accelerate Input Processing
545 GTMenu Point Coordinates and Line Incidences Commands
We encourage you to experiment with these prerelease features and provide us withsuggestions to improve these features as well as other GTSTRUDL capabilities
GT STRUDL LRFD3 Steel Design Code and Parameters
52 - 1
52 Design Prerelease Features
521 LRFD3 Steel Design Code and Parameters
LRFD3 CodeAmerican Institute of Steel Construction
Load and Resistance Factor DesignAISC LRFD Third Edition
LRFD312 LRFD3 Steel Design Code and Parameters
The LRFD3 code of GTSTRUDL may be used to select or check any of the followingshapes
Design for bi-axial bending and axial forcesI shapes Round BarsChannels Square BarsSingle Angles Rectangular BarsTees Plate GirdersDouble Angles
Design for bi-axial bending axial and torsional forcesRound HSS (Pipes)Rectangular and Square HSS (Structural Tubes)
The term I shapes is used to mean rolled or welded I and H beams and columnsuniversal beams and columns joists universal bearing piles W S M and HP profiles withdoubly symmetric cross-sections
The code is primarily based on the AISC ldquoLoad and Resistance Factor DesignSpecification for Structural Steel Buildingsrdquo adopted December 27 1999 with errataincorporated as of September 4 2001 The Specification is contained in the Third Editionof the AISC Manual of Steel Construction Load and Resistance Factor Design (96) TheLRFD3 code utilizes the Load and Resistance Factor design techniques of the AISCSpecification
Second order elastic analysis using factored loads is required by the GTSTRUDLLRFD3 code Second order effects may be considered by using GTSTRUDL NonlinearAnalysis (Section 25 or Volume 3 of the User Reference Manual) GTSTRUDL LRFD3code check does not consider the technique discussed in Section C12 of AISC Manual ofSteel Construction Load amp Resistance Factor Design Third Edition for determination ofMu (B1 and B2 factors) in lieu of a second order analysis
GT STRUDLreg
S t e e l D e s i g n C o d e U s e r M a n u a l
Volume 2 - LRFD3
Computer Aided Structural Engineering CenterSchool of Civil and Environmental Engineering
Georgia Institute of TechnologyAtlanta Georgia 30332-0355
Rev T ii V2
This page intentionally left blank
V2 iii Rev T
GTSTRUDL Users Manual Revision History
Revision No
DateReleased Description
T 2006
V2 iv Rev T
This page intentionally left blank
V2 v Rev T
NOTICES
GTSTRUDLreg User Reference Manual Volume 2 - LRFD3 Steel Design Codes RevisionT is applicable to Version 29 of GTSTRUDL released 2006 and subsequent versions
GTSTRUDLreg computer program is proprietary to and a trade secret of the Georgia TechResearch Corporation Atlanta Georgia 30332
GTSTRUDLreg is a registered service mark of the Georgia Tech Research CorporationAtlanta Georgia USA
DISCLAIMER
NEITHER GEORGIA TECH RESEARCH CORPORATION NOR GEORGIA INSTITUTEOF TECHNOLOGY MAKE ANY WARRANTY EXPRESSED OR IMPLIED AS TO THEDOCUMENTATION FUNCTION OR PERFORMANCE OF THE PROGRAMDESCRIBED HEREIN AND THE USERS OF THE PROGRAM ARE EXPECTED TOMAKE THE FINAL EVALUATION AS TO THE USEFULNESS OF THE PROGRAM INTHEIR OWN ENVIRONMENT
Commercial Software Rights Legend
Any use duplication or disclosure of this software by or for the US Government shall berestricted to the terms of a license agreement in accordance with the clause at DFARS2277202-3 (June 2005)
This material may be reproduced by or for the US Government pursuant to the copyrightlicense under the clause at DFARS 252227-7013 September 1989
Georgia Tech Research CorporationGeorgia Institute of Technology
Atlanta Georgia 30332-0355
Copyright copy 2006
Georgia Tech Research CorporationAtlanta Georgia 30332
ALL RIGHTS RESERVED
Printed in United States of America
V2 vi Rev T
This page intentionally left blank
V2 vii Rev T
Table of Contents
Chapter Page
NOTICES v
DISCLAIMER v
Commercial Software Rights Legend v
Table of Contents vii
LRFD31 GTSTRUDL Steel Design LRFD3 Code LRFD311 - 1LRFD311 Introduction LRFD311 - 1LRFD312 LRFD3 Steel Design Code and Parameters LRFD312 - 1
LRFD32 Properties used by LRFD3 LRFD32 - 1LRFD33 Parameters Used by LRFD3 LRFD33 - 1
Appendix A References A - 1Appendix B Use of GTTABLE B - 1Appendix C GTSTRUDL Tables of Steel Profiles C - 1
List of Figures
Figure LRFD31-1 Local Axes for Design with LRFD3 LRFD312 - 2Figure LRFD32-1 Local Axes for Design with LRFD3 LRFD32 - 2Figure LRFD33-1 Local Axis Buckling LRFD33 - 16Figure LRFD33-2 SIDESWAY Conditions LRFD33 - 20
List of Tables
Table LRFD31-1 LRFD3 Code Parameters LRFD312 - 9Table LRFD31-2 GTSTRUDL AISC Codes LRFD312 - 25Table LRFD31-3 GTSTRUDL Profile Tables for the Design based
on the LRFD3 Code LRFD312 - 27Table LRFD31-4 ASTM Steel Grades and Associated Values of Fy and Fu Based
on the 1999 AISC LRFD Third Edition LRFD312 - 29Table LRFD31-5 ASTM Steel Grades and Associated Values of Fy and Fu Based
on the 1999 AISC LRFD Third Edition LRFD312 - 30
V2 viii Rev T
This page intentionally left blank
GT STRUDL GTSTRUDL Steel Design LRFD3 Code
V2 LRFD311 - 1 Rev T
LRFD31 GTSTRUDL Steel Design LRFD3 Code
LRFD311 Introduction
The purpose of this volume is to discuss in detail the parameters and properties forthe GTSTRUDL steel design LRFD3 code This volume is only applicable to steel designLRFD3 code
GTSTRUDL Steel Design LRFD3 Code GT STRUDL
Rev T LRFD311 - 2 V2
This page intentionally left blank
GT STRUDL LRFD3 Steel Design Code and Parameters
V2 LRFD312 - 1 Rev T
LRFD3 CodeAmerican Institute of Steel Construction
Load and Resistance Factor DesignAISC LRFD Third Edition
LRFD312 LRFD3 Steel Design Code and Parameters
The LRFD3 code of GTSTRUDL may be used to select or check any of the followingshapes
Design for bi-axial bending and axial forcesI shapes Round BarsChannels Square BarsSingle Angles Rectangular BarsTees Plate GirdersDouble Angles
Design for bi-axial bending axial and torsional forcesRound HSS (Pipes)Rectangular and Square HSS (Structural Tubes)
The term I shapes is used to mean rolled or welded I and H beams and columnsuniversal beams and columns joists universal bearing piles W S M and HP profiles withdoubly symmetric cross-sections
The code is primarily based on the AISC ldquoLoad and Resistance Factor DesignSpecification for Structural Steel Buildingsrdquo adopted December 27 1999 with errataincorporated as of September 4 2001 The Specification is contained in the Third Editionof the AISC Manual of Steel Construction Load and Resistance Factor Design (96) TheLRFD3 code utilizes the Load and Resistance Factor design techniques of the AISCSpecification
Second order elastic analysis using factored loads is required by the GTSTRUDLLRFD3 code Second order effects may be considered by using GTSTRUDL NonlinearAnalysis (Section 25 or Volume 3 of the User Reference Manual) GTSTRUDL LRFD3code check does not consider the technique discussed in Section C12 of AISC Manual ofSteel Construction Load amp Resistance Factor Design Third Edition for determination ofMu (B1 and B2 factors) in lieu of a second order analysis
LRFD3 Steel Design Code and Parameters GT STRUDL
Rev T LRFD312 - 2 V2
Figure LRFD31-1 Local Axes for Design with LRFD3
GT STRUDL LRFD3 Steel Design Code and Parameters
V2 LRFD312 - 3 Rev T
Figure LRFD31-1 Local Axes for Design with LRFD3 (continued)
LRFD3 Steel Design Code and Parameters GT STRUDL
Rev T LRFD312 - 4 V2
Figure LRFD31-1 Local Axes for Design with LRFD3 (Continued)
GT STRUDL LRFD3 Steel Design Code and Parameters
V2 LRFD312 - 5 Rev T
The following assumptions are made throughout the LRFD3 code
1 Open cross-sections (I shapes channels single angles double angles teesbars and plate girders) are normally not used in situations whereinsignificant torsional moments must be resisted by the member Torsionalstresses are usually small for open cross-sections when compared to axial andbending stresses and may be neglected No checks are made for torsion inopen cross-sections (I shapes channels single angles double angles teesbars and plate girders) The designer is reminded to check the torsionalstresses for open cross-sections (I shape channels single angles doubleangles tees bars and plate girders) whenever they become significant
2 Torsional stresses are checked for round HSS (pipes) rectangular and squareHSS (structural tubes) based on the Section 61 on Page 162-8 of the AISCLRFD Third Edition Combined torsion shear flexure andor axial forcesare also checked for round HSS (pipes) rectangular and square HSS(structural tubes) based on the Section 72 on Page 162-10 of the AISCLRFD Third Edition Closed cross-sections (HSS) are frequently used insituations wherein significant torsional moments must be resisted by themembers Generally the normal and shear stresses due to warping in closedcross-sections (HSS) are insignificant and the total torsional moment can beassumed to be resisted by pure torsional shear stresses (Saint-Venantrsquostorsion)
3 Web stiffeners are considered for web shear stress but they are not designed4 Modified column slenderness for double angle member is considered
(Section E4 of the AISC LRFD Third Edition) Modified columnslenderness of the double angle member is computed based on the userspecified or designed number of the intermediate connectors
5 Double angles contain an adequate number of intermediate connectors (stitchplates) which make the two angles act as one Tee-like section
The sections of the AISC LRFD Third Edition specifications (96) which areconsidered by the GTSTRUDL LRFD3 code are summarized below
Section Title
Chapter D Tension membersSection B7 Limiting slenderness ratiosSection D1 Design tensile strength
LRFD3 Steel Design Code and Parameters GT STRUDL
Rev T LRFD312 - 6 V2
Section Title
Chapter E Columns and other compression membersSection B7 Limiting slenderness ratiosTable B51 Limiting width to thickness ratio for unstiffened compression
elementsTable B51 Limiting width to thickness ratio for stiffened compression
elementsSection E2 Design compressive strength for flexural bucklingSection E3 Design compressive strength for flexural-torsional bucklingSection E4 Built-up memberSection E41 Design strength Modified column slendernessSection E42 Detailing requirements
Appendix E Columns and other compression membersAppendix E3 Design compressive strength for flexural-torsional buckling
Appendix B Design requirementsAppendix B53a Unstiffened compression elementsAppendix B53b Stiffened compression elementsAppendix B53c Design propertiesSection B53d Design strength
Chapter F Beam and other flexural membersSection F11 YieldingSection F12 Lateral-Torsional BucklingSection F12a Doubly symmetric shapes and channels with Lb LrSection F12b Doubly symmetric shapes and channels with Lb gt LrSection F12c Tees and Double angles
Appendix F Beams and other flexural membersAppendix F1 Design for flexureTable A-F11 Nominal strength parameters
Appendix F2 Design for shearAppendix F22 Design shear strengthAppendix F23 Transverse stiffeners
Appendix G Plate GirdersAppendix G1 LimitationsAppendix G2 Design flexural strengthAppendix G3 Design shear strengthAppendix G4 Transverse stiffenersAppendix G5 Flexure-shear
GT STRUDL LRFD3 Steel Design Code and Parameters
V2 LRFD312 - 7 Rev T
Section Title
Chapter H Member under combined forcesSection H1 Symmetric members subject to bending and axial forceSection H11 Doubly and singly symmetric member in flexure and tensionSection H12 Doubly and singly symmetric member in flexure and
compression
Load and Resistance Factor Design Specification for Single-Angle Members
Section Title
Section 2 TensionSection 3 ShearSection 4 CompressionSection 5 FlexureSection 51 Flexure Design StrengthSection 53 Bending About Principal AxesSection 6 Combined ForcesSection 61 Members in Flexure and Axial CompressionSection 62 Members in Flexure and Axial Tension
Load and Resistance Factor Design Specification for Steel Hollow StructuralSections
Section Title
Table 22-1 Limiting Wall Slenderness for Compression Elements
Section 3 Tension MembersSection 31 Design Tensile StrengthSection 4 Column and Other Compression Members Section 42 Design Compressive StrengthSection 5 Beams and Other Flexural MembersSection 51 Design Flexural StrengthSection 52 Design Shear StrengthSection 6 Torsion MembersSection 61 Design Torsional StrengthSection 7 Members Under Combined ForcesSection 71 Design for Combined Flexure and Axial Force
LRFD3 Steel Design Code and Parameters GT STRUDL
Rev T LRFD312 - 8 V2
Section Title
Section 72 Design for Combined Torsion Shear Flexure andor AxialForce
Tensile or compressive axial strengths bi-axial bending shear strengths andcombined strengths are considered for all cross-sections Parameters allowing for thechanges which occur in structural steel at high temperatures have been included and may beinvoked at the users discretion
The detailed explanation of the code parameters and cross-section properties are asfollows
1 Table LRFD31-1 Shows the parameters used by LRFD3 codeTable LRFD31-1 contains the applicableparameter names their default values and a briefdescription of the parameters
2 Section LRFD32 Describes the cross-section properties used foreach shape
3 Section LRFD33 Contains detailed discussion of the parametersused by the LRFD3 code and they are presentedin the alphabetic order in this section
GT STRUDL LRFD3 Code Parameters
V2 LRFD312 - 9 Rev T
Table LRFD31-1LRFD3 Code Parameters
Parameter Default Name Value Meaning
CODE Required Identifies the code to be used for member checking ormember selection Specify LRFD3 for code name Secondorder elastic analysis using factored loads is required by theGTSTRUDL LRFD3 code Second order effect may beconsidered by using GTSTRUDL Nonlinear Analysis(Section 25 of Volume 3 of the User Reference Manual)See Sections LRFD32 and LRFD33 for a more detaileddescription of parameters and cross-section properties
TBLNAM WSHAPES9 Identifies the table of profiles to be used during selection(SELECT command) See Table LRFD31-3 for a list ofavailable table names
CODETOL 00 Percent variance from 10 for compliance with the provisionsof a code The ratio of ActualAllowable must be less thanor equal to [10 + CODETOL100]
PF 10 Area reduction factor for holesout in members subject toaxial tension
a 100000 The clear distance between transverse stiffeners This(inches) parameter is used to compute ah ratio which is used in the
computation of the limiting shear strength The default valueindicates that the shear check does not consider transversestiffeners
LRFD3 Code Parameters GT STRUDL
Rev T LRFD312 - 10 V2
Table LRFD31-1 (continued)
LRFD3 Code Parameters
Parameter Default Name Value Meaning
SECTYPE Computed Indicates that the cross-section is rolled or welded shapeThis parameter is used to compute the value of Fr Fr is thecompressive residual stress in flangeROLLED = rolled shape Compressive residual stress is
equal to 10 ksi WELDED = welded shape Compressive residual stress
is equal to 165 ksi
Material Properties
STEELGRD A36 Identifies the grade of steel from which a member is madeSee Tables LRFD31-4 and LRFD31-5 for steel grades andtheir properties
Fy Computed Yield stress of member Computed from parameterlsquoSTEELGRDrsquo if not given
Fu Computed Minimum tensile strength of member Computed fromparameter lsquoSTEELGRDrsquo if not given
Fyf Fy Minimum yield stress of the flange If not specified it isassumed equal to the parameter lsquoFyrsquo This parameter is usedto define a hybrid cross-section See parameter lsquoFywrsquo also
Fyw Fy Minimum yield stress of the web If not specified it isassumed equal to the parameter lsquoFyrsquo This parameter is usedto define a hybrid cross-section See parameter lsquoFyfrsquo also
RedFy 10 Reduction factor for parameter lsquoFyrsquo This factor timesparameter lsquoFyrsquo gives the Fy value used by the code Used toaccount for property changes at high temperatures
GT STRUDL LRFD3 Code Parameters
V2 LRFD312 - 11 Rev T
Table LRFD31-1 (continued)
LRFD3 Code Parameters
Parameter Default Name Value Meaning
Material Properties (continued)
RedFu 10 Reduction factor for parameter lsquoFursquo Similar to parameterlsquoRedFyrsquo
REDE 10 Reduction factor for E the modulus of elasticity Similar toparameter RedFy
Slenderness Ratio
SLENCOMP 200 Maximum permissible slenderness ratio (KLr) for amember subjected to axial compression When no value isspecified for this parameter the value of 200 is used for themaximum slenderness ratio
SLENTEN 300 Maximum permissible slenderness ratio (Lr) for a membersubjected to axial tension When no value is specified forthis parameter the value of 300 is used for the maximumslenderness ratio
K-Factors
COMPK NO Parameter to request the computation of the effective lengthfactors KY and KZ (Sections 22 and 23 of Volume 2A ofthe User Reference Manual)YES = compute KY and KZ factorsKY = compute KY onlyKZ = compute KZ onlyNO = use default or specified values for KY and
KZ
K-factor Leaning Columns Concept has not been implemented for the automatic K-factor Computation
LRFD3 Code Parameters GT STRUDL
Rev T LRFD312 - 12 V2
Table LRFD31-1 (continued)
LRFD3 Code Parameters
Parameter Default Name Value Meaning
K-Factors (continued)
KY 10 Effective length factor for buckling about the local Y axis ofthe profile See Sections 22 and 23 of Volume 2A of theUser Reference Manual for GTSTRUDL computation ofeffective length factor KY
KZ 10 Effective length factor for buckling about the local Z axis ofthe profile See Sections 22 and 23 of Volume 2A of theUser Reference Manual for GTSTRUDL computation ofeffective length factor KZ
Print-K YES Parameter to print the computed K-factor values after thedefault code check or select command output (TRACE 4output) The default value of lsquoYESrsquo for this parameterindicates that the computed K-factor values should beprinted after the code check or select command output Thecolumn names attached to the start and end of the codechecked member is also printed This printed informationallows the user to inspect the automatic detection of thecolumns attached to the start and end of the designedmember A value of lsquoNOrsquo indicates that K-factor values andthe names of the attached columns to the start and end of thedesigned member should not be printed
SDSWAYY YES Indicates the presence or absence of sidesway about thelocal Y axis YES = sidesway permittedNO = sidesway prevented
K-factor Leaning Columns Concept has not been implemented for the automatic K-factor Computation
GT STRUDL LRFD3 Code Parameters
V2 LRFD312 - 13 Rev T
Table LRFD31-1 (continued)
LRFD3 Code Parameters
Parameter Default Name Value Meaning
K-Factors (continued)
SDSWAYZ YES Indicates the presence or absence of sidesway about the localZ axis YES = sidesway permittedNO = sidesway prevented
CantiMem NO Parameter to indicate that a member or a physical memberwhich is part of a cantilever truss should be considered as acantilever in the K-factor computation True cantilevermembers or physical members are detected automaticallyNO = member or physical member is not cantileverYES = member or physical member is cantilever
GAY Computed G-factor at the start joint of the member GAY is used in thecalculation of effective length factor KY (see parametersCOMPK KY and Sections 22 and 23 of Volume 2A of theUser Reference Manual)
GAZ Computed G-factor at the start joint of the member GAZ is used in thecalculation of effective length factor KZ (see parametersCOMPK KZ and Sections 22 and 23 of Volume 2A of theUser Reference Manual)
GBY Computed G-factor at the end joint of the member GBY is used in thecalculation of effective length factor KY (see parametersCOMPK KY and Sections 22 and 23 of Volume 2A of theUser Reference Manual)
GBZ Computed G-factor at the end joint of the member GBZ is used in thecalculation of effective length factor KZ (see parametersCOMPK KZ and Sections 22 and 23 of Volume 2A of theUser Reference Manual)
LRFD3 Code Parameters GT STRUDL
Rev T LRFD312 - 14 V2
Table LRFD31-1 (continued)
LRFD3 Code Parameters
Parameter Default Name Value Meaning
Buckling Length
LY Computed Unbraced length for buckling about the local Y axis of theprofile The default is computed as the length of the mem-ber
LZ Computed Unbraced length for buckling about the local Z axis of theprofile The default is computed as the length of the mem-ber
FRLY 10 Fractional form of the parameter LY allows unbraced lengthto be specified as fractions of the total length Used onlywhen LY is computed
FRLZ 10 Fractional form of the parameter LZ similar to FRLY Usedonly when LZ is computed
Flexural-Torsional Buckling
KX 10 Effective length factor for torsional buckling about the localX axis of the profile This parameter is used in flexural-torsional buckling stress Fe computations
LX Computed Unbraced length for torsional buckling about the local X axisof the profile The default is computed as the length of themember This parameter is used in flexural-torsionalbuckling stress Fe computations
FRLX 10 Fractional form of the parameter LX allows unbraced lengthto be specified as fractions of the total length Used onlywhen LX is computed
GT STRUDL LRFD3 Code Parameters
V2 LRFD312 - 15 Rev T
Table LRFD31-1 (continued)
LRFD3 Code Parameters
Parameter Default Name Value Meaning
Bending Strength
CB Computed Coefficient used in computing allowable compressivebending strength (AISC LRFD Third Edition Section F12aEquation F1-3)
UNLCF Computed Unbraced length of the compression flange The default iscomputed as the length of the member In this parameter nodistinction is made between the unbraced length for the topor bottom flange See UNLCFTF or UNLCFBF
FRUNLCF 10 Fractional form of the parameter UNLCF allows unbracedlength to be specified as fractions of the total length Usedonly when UNLCF is computed
UNLCFTF Computed Unbraced length of the compression flange for the topflange When no value is specified UNLCF and FRUNLCFare used for this parameter
UNLCFBF Computed Unbraced length of the compression flange for the bottomflange When no value is specified UNLCF and FRUNLCFare used for this parameter
LRFD3 Code Parameters GT STRUDL
Rev T LRFD312 - 16 V2
Table LRFD31-1 (continued)
LRFD3 Code Parameters
Parameter Default Name Value Meaning
Channel Parameter
Tipping YES This is the parameter indicating that the tipping effect shouldbe considered When the load is applied to the top flange ofthe channel and the flange is not braced there is a tippingeffect that reduces the critical moment A value of YES forthis parameter indicates that the flange is unbraced and theflange is loaded as such that causes tipping effect In thiscase the reduced critical moment may be conservativelyapproximated by setting the warping buckling factor X2
equal to zero A value of NO indicates that the tipping effectdoes not happen and the warping buckling factor iscomputed based on the Equation F1-9 of the AISC LRFDThird Edition
Single Angle Parameter
Cby Computed Coefficient used in computing elastic lateral-torsionalbuckling moment Mob (AISC LRFD Third Edition Section53 on the page 163-6) for major axis bending (bendingabout the principal Y axis)
Tee Parameter
SFYBend 10 Parameter to specify safety factor for the computation of thelimit state of Y axis (minor axis) bending of the tee section
Double Angle Parameters
nConnect 0 Number of connectors between individual angles The userspecified value is used during the code check When theSELECT MEMBER (design) is requested the user specifiedvalue is used unless more connectors are required If the
GT STRUDL LRFD3 Code Parameters
V2 LRFD312 - 17 Rev T
Table LRFD31-1 (continued)
LRFD3 Code Parameters
Parameter Default Name Value Meaning
Double Angle Parameters (continued)
designed number of connectors are larger than the userspecified value the computed number of connectors are usedand printed after the SELECT MEMBER result Thedefault value of zero indicates that the angles are connectedat the ends only Following are additional options that youcan specify for this parameter0 = angles are connected at the ends of the memberndash1 = requesting the number of connectors to be computed
during code checkndash2 = bypass modified column slenderness equations
This will bypass the check for the Section E41 ofthe AISC LRFD Third Edition
ConnType WELDED Type of the intermediate connectors that are used for doubleangle Choices are SNUG and WELDEDSNUG = intermediate connectors that are snug-tight
boltedWELDED = intermediate connectors that are welded or
fully tensioned bolted This is the default
L Computed Actual member length is used to design a number ofconnectors and to check connector spacing (Section E42 ofthe AISC LRFD) and also used in the computation of themodified column slenderness (KLr)m (Section E41 of theAISC LRFD) This parameter is used to compute thedistance between connectors a = L(n+1) where lsquoarsquo is thedistance between connectors lsquoLrsquo is the physical memberlength and lsquonrsquo is the number of connectors The default iscomputed as the length of the member
LRFD3 Code Parameters GT STRUDL
Rev T LRFD312 - 18 V2
Table LRFD31-1 (continued)
LRFD3 Code Parameters
Parameter Default Name Value Meaning
Double Angle Parameters (continued)
K 10 Effective length factor for an individual component (singleangle) This parameter is used to design a number ofconnectors and to check the connector spacing (Section E42of the AISC LRFD)
SFYBend 10 Parameter to specify safety factor for the computation of thelimit state of Y axis (minor axis) bending of the double anglesection
Round HSS (Pipes) Shear Check Parameters
avy Computed The length of essentially constant shear in the Y axisdirection of a member This parameter is used to check theY direction shear of a round HSS (pipe) cross-section (96)This parameter is similar to the variable lsquoarsquo in the Equation52-2 of the AISC LRFD HSS specification in the Section162 of the LRFD Third Edition The default is computed asthe length of the member
avz Computed The length of essentially constant shear in the Z axisdirection of a member This parameter is used to check theZ direction shear of a round HSS (pipe) cross-section (96)This parameter is similar to the variable lsquoarsquo in the Equation52-2 of the AISC LRFD HSS specification in the Section162 of the LRFD Third Edition The default is computed asthe length of the member
GT STRUDL LRFD3 Code Parameters
V2 LRFD312 - 19 Rev T
Table LRFD31-1 (continued)
LRFD3 Code Parameters
Parameter Default Name Value Meaning
Round HSS (Pipes) Torsion Check Parameter
LX Computed This parameter is to specify the distance between torsionalrestraints LX is used in the equation 61-2 on Page 162-8of AISC LRFD Third Edition (96) This parameter is similarto the variable lsquoarsquo in the Equation 52-2 of the AISC LRFDHSS specification in the Section 162 of the LRFD ThirdEdition The default is computed as the length of the mem-ber
Rectangular Hollow Structural Section (HSS) Parameters
Cby Computed Coefficient used in computing limiting compressive bendingstrength (AISC LRFD Third Edition Section F12aEquation F1-3) for minor axis bending (bending about the Y-axis)
UNLCW Computed Unbraced length of the compression web about the local Yaxis of the profile The default is taken as length of member
FRUNLCW Computed Fractional form of the parameter UNLCW allows unbracedlength to be specified as a fraction of the total length Usedonly when UNLCW is computed
Plate Girder Parameters
Fyst Fy Minimum yield stress of the transverse stiffeners materialIf not specified it is assumed equal to the parameter Fy
LRFD3 Code Parameters GT STRUDL
Rev T LRFD312 - 20 V2
Table LRFD31-1 (continued)
LRFD3 Code Parameters
Parameter Default Name Value Meaning
Plate Girder Parameters (continued)
Ast 00 Parameter to specify the transverse stiffeners area Thisparameter is used to check Appendix G4 of AISC LRFD 3rd
Edition The specified transverse stiffeners area is checkedto see if it is smaller than the computed value from EquationA-G4-1 of Appendix G4 of AISC LRFD 3rd Edition Thedefault value of 00 indicates that the transverse stiffenersarea of Appendix G4 is not checked
Ist 00 Parameter to specify the transverse stiffeners moment ofinertia This parameter is used to check Appendix F23 ofAISC LRFD 3rd Edition for the required transverse stiffenersmoment of inertia The default value of 00 indicates that thetransverse stiffeners moment of inertia according toAppendix F23 is not checked
Dstiff 24 Parameter to specify the factor D that is used in the EquationA-G4-1 of Appendix G4 of AISC LRFD 3rd Edition Adefault value of 24 for single plate stiffeners is assumedThe value of factor D (parameter lsquoDstiffrsquo) in the Equation A-G4-1 is dependent on the type of transverse stiffeners usedin a plate girder Alternate values are as follows10 = for stiffeners in pairs This is the default value
when the specified value for the parameterlsquoNumBarsrsquo is greater than 1
18 = for single angle stiffeners24 = for single plate stiffeners This is the default
value when the specified value for the parameterlsquoNumBarsrsquo is equal to 1
GT STRUDL LRFD3 Code Parameters
V2 LRFD312 - 21 Rev T
Table LRFD31-1 (continued)
LRFD3 Code Parameters
Parameter Default Name Value Meaning
Plate Girder Parameters (continued)
NumBars 10 Parameter to specify a number of single plate stiffeners Thedefault value for this parameter indicates 1 single platestiffener
Stiff-H 00 Parameter to specify the single plate stiffeners cross-sectionrsquos height Parameters lsquoStiff-Hrsquo lsquoStiff-Wrsquo andlsquoNumBarsrsquo are used for the automatic computation of theparameters lsquoAstrsquo and lsquoIstrsquo The automatic computation of theparameters lsquoAstrsquo and lsquoIstrsquo is based on the rectangular barstiffeners geometry If transverse stiffeners are notrectangular bar parameters lsquoAstrsquo and lsquoIstrsquo should bespecified
Stiff-W 00 Parameter to specify the single plate stiffeners cross-sectionrsquos width See parameter lsquoStiff-Hrsquo for moreinformation
Force Limitation
FXMIN 05 (lb) Minimum axial force to be considered by the code anythingless in magnitude is taken as zero
FYMIN 05 (lb) Minimum Y-shear force to be considered by the codeanything less in magnitude is taken as zero
FZMIN 05 (lb) Minimum Z-shear force to be considered by the codeanything less in magnitude is taken as zero
LRFD3 Code Parameters GT STRUDL
Rev T LRFD312 - 22 V2
Table LRFD31-1 (continued)
LRFD3 Code Parameters
Parameter Default Name Value Meaning
Force Limitation (continued)
MXMIN 200 (in-lb) Minimum torsional moment to be considered by the codeanything less in magnitude is taken as zero
MYMIN 200 (in-lb) Minimum Y-bending moment to be considered by the codeanything less in magnitude is taken as zero
MZMIN 200 (in-lb) Minimum Z-bending moment to be considered by the codeanything less in magnitude is taken as zero
Output Processing and System Parameters
SUMMARY NO Indicates if SUMMARY information is to be saved for themember Choices are YES or NO see Sections 29 and 72of Volume 2A of the User Reference Manual for an expla-nation
PrintLim NO Parameter to request to print the section limiting values forlimit state and load and resistance factor codes The defaultoutput from CHECK or SELECT command prints thesection force values A value of lsquoYESrsquo for this parameterindicates that the section limiting values should be printedinstead of default section forces
GT STRUDL LRFD3 Code Parameters
V2 LRFD312 - 23 Rev T
Table LRFD31-1 (continued)
LRFD3 Code Parameters
Parameter Default Name Value Meaning
Output Processing and System Parameters (continued)
TRACE 40 Flag indicating when checks of code provisions should beoutput during design or code checking See Section 72 ofVolume 2A of the User Reference Manual for anexplanation1 = never2 = on failure3 = all checks4 = controlling ActualAllowable values and section
forces
VALUES 10 Flag indicating if parameter or property values are to beoutput when retrieved See Section 72 of Volume 2A of theUser Reference Manual for the explanation1 = no output2 = output parameters3 = output properties4 = output parameters and properties
LRFD3 Code Parameters GT STRUDL
Rev T LRFD312 - 24 V2
This page intentionally left blank
GT STRUDL LRFD3 Steel Design Code and Parameters
V2 LRFD312 - 25 Rev T
Table LRFD31-2GTSTRUDL AISC Codes
Code ParameterName Table Application
LRFD3 LRFD31-1 Checks compliance of I shapes channels single angles teesVolume double angles round HSS (pipes) rectangular and square 2 - LRFD3 HSS (structural tubes) solid round square and rectangular
bars and plate girder profiles to the 1999 AISC LRFDThird Edition Specification (96)
ASD9-E ASD9-E1-1 Checks compliance of I shape profiles to the 1989 AISCVolume ASD Ninth Edition specification (72) with equations that 2 - ASD9-E have been modified to include the modulus of elasticity
(constant E) LRFD2 LRFD2 Checks compliance of I shapes pipes structural tubing plate
Volume 2A girders (subjected to bi-axial bending and axial force)single and double angles (subjected to axial forces only)shape profiles to the 1993 AISC LRFD Second EditionSpecification (81)
ASD9 ASD9 Checks compliance of I shapes single angles channels teesVolume 2A double angles solid round bars pipes solid squares and
rectangular bars and structural tubing shape profiles to the1989 AISC ASD Ninth Edition Specification (72)
78AISC 2231 Checks compliance of I shapes single angles channels teesVolume 2B solid round bars pipes solid squares and rectangular bars
and structural tubing (use code name DBLANG for doubleangle) shape profiles to the 1978 AISC Specification (33)Eighth Edition including 1980 updates
For latest (up to date) version of this table see Table 21-1a of Volume 2A
LRFD3 Steel Design Code and Parameters GT STRUDL
Rev T LRFD312 - 26 V2
Table LRFD31-2 (continued)GTSTRUDL AISC Codes
Code ParameterName Table Application
69AISC 2231 Checks compliance of I shapes single angles channels teesVolume 2B solid round bars pipes solid squares and rectangular bars
and structural tubing (use code name DBLANG for doubleangle) shape profiles to the 1969 AISC Specification (16)Seventh Edition including supplements 1 2 and 3
W78AISC 2231 Similar to 78AISC code except limited to checking I shapeVolume 2B profiles This code is identical to the 78AISC code which
was available in older versions of GTSTRUDL (ie versionV1M7 and older)
DBLANG 2231 Checks compliance of double angle profiles to the 1969 Volume 2B AISC Specification (16) Seventh Edition including supple-
ments 1 2 and 3
W69AISC 2231 Similar to 69AISC code except limited to checking I shapeVolume 2B profiles This code is identical to the 69AISC code which
was available in older versions of GTSTRUDL (ie versionV1M7 and older)
For latest (up to date) version of this table see Table 21-1a of Volume 2A
GT STRUDL LRFD3 Steel Design Code and Parameters
V2 LRFD312 - 27 Rev T
Table LRFD31-3GTSTRUDL Profile Tables for theDesign based on the LRFD3 Code
Profile Shapes Reference
I shapes See Appendix C of Volume 2A for list of applicable table namesfor I shapes W S M HP shapes wide flange shapes universalbeam shapes universal column shapes etc
Channels See Appendix C of Volume 2A for a list of channel table namesapplicable to LRFD3 codes
Single Angles See Appendix C of Volume 2A for list of single angle tablenames applicable to LRFD3 code
Tees See Appendix C of Volume 2A for a list of tee table namesapplicable to LRFD3 codes
Double Angles See Appendix C of Volume 2A for list of double angle tablenames applicable to LRFD3 code
Round HSS See Appendix C of Volume 2A for list of round HSS (pipecircular hollow section) table names applicable to LRFD3 code
Rectangular HSS See Appendix C of Volume 2A for list of rectangular and squareHSS (structural tube rectangular and square hollow section) tablenames applicable to LRFD3 code
Solid Round Bars See Appendix C of Volume 2A for a list of solid round bar tablenames applicable to LRFD3 codes
Solid Square Bars See Appendix C of Volume 2A for a list of solid square bar tablenames applicable to LRFD3 codes
Solid Rectangular Bars See Appendix C of Volume 2A for a list of solid rectangular bartable names applicable to LRFD3 codes
Plate Girders See Appendix C of Volume 2A for a list of plate girder tablenames applicable to LRFD3 codes
LRFD3 Steel Design Code and Parameters GT STRUDL
Rev T LRFD312 - 28 V2
Table LRFD31-4
ASTM Steel Grades and Associated Values of Fy and Fu Based on the1999 AISC LRFD Third Edition Specifications
Applicable Shapes W M S HP L 2L C MC WT MT and STshapes from AISC Tables
Steel GradeASTM
Designation
Group Number Per ASTM A6Fy Minimum Yield Stress (ksi)
Fu Minimum Tensile Strength (ksi)
Group 1 Group 2 Group 3 Group 4 Group 5
A36 3658
3658
3658
3658
3658
A529-G50 5065
5065
NA NA NA
A529-G55 5570
5570
NA NA NA
A572-G42 4260
4260
4260
4260
4260
A572-G50 5065
5065
5065
5065
5065
A572-G55 5570
5570
5570
5570
5570
A572-G60 6075
6075
6075
NA NA
A572-G65 6580
6580
6580
NA NA
A913-G50 5060
5060
5060
5060
5060
A913-G60 6075
6075
6075
6075
6075
A913-G65 6580
6580
6580
6580
6580
A913-G70 7090
7090
7090
7090
7090
GT STRUDL LRFD3 Steel Design Code and Parameters
V2 LRFD312 - 29 Rev T
Table LRFD31-4 (continued)
ASTM Steel Grades and Associated Values of Fy and Fu Based on the1999 AISC LRFD Third Edition Specifications
Applicable Shapes W M S HP L 2L C MC WT MT and ST shapes from AISC Tables
Steel GradeASTM
Designation
Group Number Per ASTM A6Fy Minimum Yield Stress (ksi)
Fu Minimum Tensile Strength (ksi)
Group 1 Group 2 Group 3 Group 4 Group 5
A992a 5065
5065
5065
5065
5065
A242 5070
5070
46b
67b42a
63a42a
63a
A588 5070
5070
5070
5070
5070
a Applicable to W shapes onlyb Applicable to W and HP shapes onlyNA Indicates that shapes in the corresponding group are not produced for that grade of steel
GTSTRUDL assumes Fy and Fu to be zero in such cases and will not select profiles for thesecombinations of group number and steel grade Minimum yield stresses (Fy) and minimumtensile strengths (Fu) were obtained from the summary of ASTM specifications included in the1999 AISC LRFD Third Edition specification
LRFD3 Steel Design Code and Parameters GT STRUDL
Rev T LRFD312 - 30 V2
Table LRFD31-5
ASTM Steel Grades and Associated Values of Fy and Fu Based on the1999 AISC LRFD Third Edition Specifications
Applicable Shapes Round HSS Steel Pipe and Rectangular HSS
Steel GradeASTM
Designation
Applicable Shape SeriesFy Minimum Yield Stress (ksi)
Fu Minimum Tensile Strength (ksi)
Round HSS Steel Pipe Rectangular HSS
A53-GB NA 3560
NA
A500-GB 4258
NA 4658
A500-GC 4662
NA 5062
A501 3658
NA 3658
A618-GIA618-GII
Thickness 34
5070 NA
5070
A618-GIA618-GII
Thickness gt 34
4667 NA
4667
A618GIII 5065
NA 5065
A242-G46 NA NA 4667
A242-G50 NA NA 5070
A588 NA NA 5070
A847 5070
NA 5070
NA Not applicable See Table LRFD31-4 for more explanation
GT STRUDL Properties Used by LRFD3
V2 LRFD32 - 1 Rev T
LRFD32 Properties Used by LRFD3
This section describes the profile properties used by the LRFD3 code Since eachshape has different properties that are required by the design code the properties of eachshape are listed separately The tables supplied with GTSTRUDL contain these propertiesrequired for design in addition to the properties required for analysis New tables createdby the user should include the same properties if the LRFD3 code is to be used Theorientation of the principal axes (Z and Y) for each shape is shown in Figure LRFD32-1
Properties Used by LRFD3 GT STRUDL
Rev T LRFD32 - 2 V2
Figure LRFD32-1 Local Axes for Design with LRFD3
GT STRUDL Properties Used by LRFD3
V2 LRFD32 - 3 Rev T
Figure LRFD32-1 Local Axes for Design with LRFD3 (Continued)
Properties Used by LRFD3 GT STRUDL
Rev T LRFD32 - 4 V2
I shapes
For W shapes and other doubly symmetric I beams the following propertiesare required
AX = cross-sectional areaAY = Y axis shear area computed as the profile depth times the web
thicknessAZ = Z axis shear area computed as 23 of the total flange areaIX = torsional moment of inertiaIY = moment of inertia about the Y axisIZ = moment of inertia about the Z axisRY = radius of gyration about the Y axisRZ = radius of gyration about the Z axisSY = section modulus about the Y axisSZ = section modulus about the Z axisZY = plastic section modulus about the Y axisZZ = plastic section modulus about the Z axisFLTK = flange thicknessWBTK = web thicknessYD = profile depthYC = positive Y direction distance from the Z axis to the extreme fiber
along the Y axis (half of the profile depth)ZD = flange widthZC = positive Z direction distance from the Y axis to the extreme fiber
along the Z axis (half of the flange width)INTYD = clear depth of the web computed as the profile depth minus twice
the flange thicknessBF2TF = bt ratio of the flange computed as 12 the flange width divided by
the flange thicknessHTW = htw assumed web depth for stability (h) divided by the web
thickness where h is the clear distance between flanges less thefillet or corner radius for rolled shapes (see AISC Manual of SteelConstruction Load amp Resistance Factor Design Third EditionDecember 1999) When htw is not specified for the cross-sectionin the GTSTRUDL or USER tables the value of INTYD dividedby the WBTK is used INTYD is the clear distance betweenflanges and WBTK is the thickness of the web
GT STRUDL Properties Used by LRFD3
V2 LRFD32 - 5 Rev T
CW = warping constant If not specified it is computed asZD3(YDndashFLTK)2(FLTK)240
ND = nominal depthWEIGHT = weight per unit lengthGRPNUM = 10SHAPE = a number that indicates the profile shape
= 10 W shapes= 11 S shapes= 12 HP shapes= 13 M shapes
Properties Used by LRFD3 GT STRUDL
Rev T LRFD32 - 6 V2
Channels
For Channels the following properties are required
AX = cross-sectional areaAY = Y axis shear area computed as the profile depth times the web
thicknessAZ = Z axis shear area computed as 23 of the total flange areaIX = torsional moment of inertiaIY = moment of inertia about the Y axisIZ = moment of inertia about the Z axisRY = radius of gyration about the Y axisRZ = radius of gyration about the Z axisSY = negative direction section modulus about the Y axis (IY(ZD-ZC))SYS = positive direction section modulus about the Y axis (IYZC)SZ = section modulus about the Z axisZY = plastic section modulus about the Y axisZZ = plastic section modulus about the Z axisFLTK = flange thicknessWBTK = web thicknessYD = profile depthYC = positive Y direction distance from the Z axis to the extreme fiber
along the Y axis (half of the profile depth)ZD = flange widthZC = positive Z direction distance from the Y axis to the extreme fiber
along the Z axis (from Y axis to the web extreme fiber)INTYD = clear depth of the web computed as the profile depth minus twice
the flange thicknessEY = distance from centroid to shear center parallel to the Y axisEZ = distance from centroid to shear center parallel to the Z axisND = nominal depthCW = warping constant If not specified it is computedWEIGHT = weight per unit lengthGRPNUM = 10SHAPE = a number that indicates the profile shape
= 20 Standard Channels (C)= 21 Miscellaneous Channels (MC)
GT STRUDL Properties Used by LRFD3
V2 LRFD32 - 7 Rev T
Single Angles
For Single Angles the properties are in principal axes the following proper-ties are required
AX = cross-sectional areaAY = Y-shear area along the Y-principle axis AY is taken as a value
that will produce the maximum transverse shear from the equationFYAY where FY is the Y-shear force in the Y-principle axisdirection In this case AY is taken as the term (IZtimesTHICKQZ)where QZ is the first moment of the area above the Z-principleaxis about the Z-principle axis See SP Timoshenko and J MGere Mechanics of Materials D Von Nostrand New York 1972
AZ = Z-shear area along the Z-principle axis AZ is taken as a valuethat will produce the maximum transverse shear from the equationFZAZ where FZ is the Z-shear force in the Z-principle axisdirection In this case AZ is taken as the term (IYtimesTHICKQY)where QY is the first moment of the area above the Y-principleaxis about the Y-principle axis See SP Timoshenko and JMGere Mechanics of Materials D Von Nostrand New York 1972
IX = torsional moment of inertiaIY = moment of inertia about the principal Y axisIZ = moment of inertia about the principal Z axisRY = radius of gyration about the principal Y axisRZ = radius of gyration about the principal Z axisSY = positive direction section modulus about the principal Y axis
(IYZC)SYS = negative direction section modulus about the principal Y axis
(IY(ZD-ZC)) (note if both legs are equal LEG1 = LEG2 thenSY = SYS)
SZ = positive direction section modulus about the principal Z axis(IZYC)
SZS = negative direction section modulus about the principal Z axis(IZ(YD-YC))
ZY = plastic section modulus about the principal Y axisZZ = plastic section modulus about the principal Z axisTHICK = thickness of the single angleLEG1 = length of the longer legLEG2 = length of the shorter legYD = depth parallel to principal Y axis
Properties Used by LRFD3 GT STRUDL
Rev T LRFD32 - 8 V2
= LEG2timescos (ALPHA)+THICKtimessin (ALPHA)YC = positive Y direction distance from the principal Z axis to the
extreme fiber along the principal Y axisZD = depth parallel to principal Z axis
= LEG1timescos (ALPHA) + LEG2timessin (ALPHA)ZC = positive Z direction distance from the principal Y axis to the
extreme fiber along the principal Z axisALPHA = angle between the longer leg of the angle and the principal Z axisEY = distance from centroid to shear center parallel to the principal Y
axisEZ = distance from centroid to shear center parallel to the principal Z
axisCW = warping constant If not specified it is computed as
((LEG1ndashTHICK2)3 + (LEG2ndashTHICK2)3)THICK336WEIGHT = weight per unit lengthGRPNUM = 10SHAPE = a number that indicates the profile shape
= 30 single angles
GT STRUDL Properties Used by LRFD3
V2 LRFD32 - 9 Rev T
Tees
For Tees the following properties are required
AX = cross-sectional areaAY = Y axis shear area computed as 23 of the profile depth times web
thicknessAZ = Z axis shear area computed as 23 of the total flange areaIX = torsional moment of inertiaIY = moment of inertia about the Y axisIZ = moment of inertia about the Z axisRY = radius of gyration about the Y axisRZ = radius of gyration about the Z axisSY = section modulus about the Y axisSZ = negative direction section modulus about the Z axis
(IZ(YD-YC))SZS = positive direction section modulus about the Z axis (IZYC)ZY = plastic section modulus about the Y axisZZ = plastic section modulus about the Z axisFLTK = flange thicknessWBTK = web thicknessYD = profile depthYC = positive Y direction distance from the Z axis to the extreme fiber
along the Y axis (from Z axis to top-of-flange)ZD = flange widthZC = positive Z direction distance from the Y axis to the extreme fiber
along the Z axis (half of the flange width)INTYD = clear depth of the web computed as the profile depth minus the
flange thicknessBF2TF = bt ratio of the flange computed as 12 the flange width divided by
the flange thicknessHTW = htw assumed web depth for stability (h) divided by the web
thickness where h is the clear distance from bottom of the stem tothe flange less the fillet or corner radius for rolled shapes (seeAISC Manual of Steel Construction Load amp Resistance FactorDesign Third Edition December 1999) When htw is notspecified for the cross-section in the GTSTRUDL or USER tablesthe value of INTYD divided by the WBTK is used INTYD is theprofile depth minus the flange thickness and WBTK is thethickness of the web
Properties Used by LRFD3 GT STRUDL
Rev T LRFD32 - 10 V2
EY = distance from centroid to shear center parallel to the Y axisEZ = distance from centroid to shear center parallel to the Z axisND = nominal depthCW = warping constant If not specified it is computedWEIGHT = weight per unit lengthGRPNUM = 10SHAPE = a number that indicates the profile shape
= 40 WT shapes= 41 ST shapes= 43 MT shapes
GT STRUDL Properties Used by LRFD3
V2 LRFD32 - 11 Rev T
Double Angles
For Double Angles the following properties are required
AX = cross section areaAY = Y-axis shear area computed as 23 of the profile depth times twice
the leg thicknessAZ = Z-axis shear area computed as 23 of the total flange areaIX = torsional moment of inertiaIY = moment of inertia about the Y axisIZ = moment of inertia about the Z axisRY = radius of gyration about the Y axisRZ = radius of gyration about the Z axisSY = section modulus about Y axisSZ = negative direction section modulus about Z axis (IZ(YD-YC))SZS = positive direction section modulus about Z axis (IZYC)ZY = plastic section modulus about the Y axisZZ = plastic section modulus about the Z axisTHICK = thickness of the flange (note the thickness of both single angles
is assumed to be the same and uniform)LEGl = length of the longer leg of each single angle which makes up the
double angleLEG2 = length of the shorter leg of each single angle which makes up the
double angleSPACING = spacing between the single angles When each angle is in contact
SPACING equals zeroYD = depth parallel to Y axisYC = positive Y direction distance from the Z axis to the extreme fiber
along the Y axisZD = depth parallel to Z axisZC = positive Z direction distance from the Y axis to the extreme fiber
along the Z axisEY = distance from centroid to shear center parallel to the Y axisEZ = distance from centroid to shear center parallel to the Z axisCW = warping constant If not specified it is computedGRPNUM = 10SHAPE = a number that indicates the profile shape
= 44 equal legs back-to-back double angles= 45 long legs back-to-back double angles= 46 short legs back-to-back double angles
Properties Used by LRFD3 GT STRUDL
Rev T LRFD32 - 12 V2
Solid Round Bars
For Solid Round Bars the following properties are required
AX = cross-sectional areaAY = Y axis shear area computed as 34 of AXAZ = Z axis shear area computed as 34 of AXIX = torsional moment of inertiaIY = moment of inertia about the Y axisIZ = moment of inertia about the Z axisRY = radius of gyration about the Y axisRZ = radius of gyration about the Z axisSY = section modulus about the Y axisSZ = section modulus about the Z axisZY = plastic section modulus about the Y axisZZ = plastic section modulus about the Z axisYD = depth parallel to Y axis (diameter of bar)YC = distance to extreme fiber in positive Y direction (radius of bar)ZD = depth parallel to Z axis (diameter of bar)ZC = distance to extreme fiber in positive Z direction (radius of bar)GRPNUM = 10SHAPE = a number that indicates the profile shape
= 50 solid round bars
GT STRUDL Properties Used by LRFD3
V2 LRFD32 - 13 Rev T
Round HSS (Pipes)
For Round HSS (Pipes) the following properties are required
AX = cross-sectional areaAY = Y axis shear area computed as 12 of AXAZ = Z axis shear area computed as 12 of AXIX = torsional moment of inertiaIY = moment of inertia about the Y axisIZ = moment of inertia about the Z axisRY = radius of gyration about the Y axisRZ = radius of gyration about the Z axisSY = section modulus about the Y axisSZ = section modulus about the Z axisZY = plastic section modulus about the Y axisZZ = plastic section modulus about the Z axisOD = outside diameter of the pipeID = inside diameter of the pipeTHICK = thickness of the pipeYD = depth parallel to Y axis (OD)YC = distance to extreme fiber in positive Y direction (OD20)ZD = depth parallel to Z axis (OD)ZC = distance to extreme fiber in positive Z direction (OD20)ND = nominal depthGRPNUM = 10SHAPE = a number that indicates the profile shape
= 51 round HSS (pipes)
Properties Used by LRFD3 GT STRUDL
Rev T LRFD32 - 14 V2
Square and Rectangular Bars
For Square and Rectangular Bars Both the Square and Rectangular Barsrequire the following properties
AX = cross-sectional areaAY = Y axis shear area computed as 23 of AXAZ = Z axis shear area computed as 23 of AXIX = torsional moment of inertiaIY = moment of inertia about the Y axisIZ = moment of inertia about the Z axisRY = radius of gyration about the Y axisRZ = radius of gyration about the Z axisSY = section modulus about the Y axisSZ = section modulus about the Z axisZY = plastic section modulus about the Y axisZZ = plastic section modulus about the Z axisYD = depth parallel to Y axisYC = distance to extreme fiber in positive Y direction (YD2)ZD = depth parallel to Z axisZC = distance to extreme fiber in positive Z direction (ZD2)GRPNUM = 10SHAPE = a number that indicates the profile shape
= 60 square bars= 61 rectangular bars
GT STRUDL Properties Used by LRFD3
V2 LRFD32 - 15 Rev T
Square and Rectangular HSS (Structural Tubing)
For Square and Rectangular HSS (Structural Tubing) the following properties arerequired
AX = cross-sectional areaAY = Y axis shear area computed as twice the web thickness times the
flat width of the webAZ = Z axis shear area computed as twice the flange thickness times the
flat width of the flangeIX = torsional moment of inertiaIY = moment of inertia about the Y axisIZ = moment of inertia about the Z axisRY = radius of gyration about Y axisRZ = radius of gyration about Z axisSY = section modulus about Y axisSZ = section modulus about Z axisZY = plastic section modulus about the Y axisZZ = plastic section modulus about the Z axisFLTK = flange thicknessWBTK = web thicknessYD = profile depthYC = positive Y direction distance from the Z axis to the extreme fiber
along the Y axis (YD2)ZD = profile widthZC = positive Z direction distance from the Y axis to the extreme fiber
along the Z axis (ZD2)INTYD = flat width of the web (YD-2timesFLTK-2timesradius)INTZD = flat width of the flange (ZD-2timesWBTK-2timesradius)EY = distance from centroid to shear center parallel to the Y axisEZ = distance from centroid to shear center parallel to the Z axisND = nominal depthCW = warping constant If not specified it is computedGRPNUM = 10SHAPE = a number that indicates the profile shape
= 62 structural tubing
It is assumed that the outside radius of the corners of a structural tube equals twicethe thickness of the tube
radius = 2 times FLTK
Properties Used by LRFD3 GT STRUDL
Rev T LRFD32 - 16 V2
This page intentionally left blank
GT STRUDL Parameters Used by LRFD3
V2 LRFD33 - 1 Rev T
LRFD33 Parameters Used by LRFD3
The parameters used by LRFD3 code may be grouped into three general categories
1 System parameters 2 Control parameters 3 Code parameters
The system parameters are used to monitor the SELECT and CHECK commandresults Control parameters decide which provisions are to be checked and specifycomparison tolerances The code parameters are used to specify information and coefficientsdirectly referenced in the code With the notable exception of CODETOL parameters of thesecond group are seldom used A knowledge of the system and control parameters allowsthe user greater flexibility when using the LRFD3 code The vast majority of parameters fallinto the code category and have a direct bearing on LRFD3 code and the results it produces
For the categories described above the parameters used by LRFD3 code are present-ed below and are summarized in the Table LRFD33-1 The system and control parametersare discussed first followed by the code parameters
Parameters Used by LRFD3 GT STRUDL
Rev T LRFD33 - 2 V2
Table LRFD331
Parameters in LRFD3
Parameter Default Alternate Name Value Values
a 100000 (in) Real value in active unitsAst 00 Real value in active unitsavy Member Length Real value in active unitsavz Member Length Real value in active unitsCantiMem NO YESCB Computed Real valueCby Computed Real valueCODE Required LRFD3CODETOL 00 Percent ToleranceCOMPK NO YES KY KZConnType WELDED SNUGDstiff 24 10 18FRLX 10 Fraction of member lengthFRLY 10 Fraction of member lengthFRLZ 10 Fraction of member lengthFRUNLCF 10 Fraction of member lengthFRUNLCW 10 Fraction of member lengthFu Computed Real value in active unitsFXMIN 05 (lb) Real value in active unitsFy Computed Real value in active unitsFyf Fy Real value in active unitsFYMIN 05 (lb) Real value in active unitsFyst Fy Real value in active unitsFyw Fy Real value in active unitsFZMIN 05 (lb) Real value in active unitsGAY Computed Real valueGAZ Computed Real valueGBY Computed Real valueGBZ Computed Real valueIst 00 Real value in active unitsK 10 Real valueKX 10 Real valueKY 10 Real valueKZ 10 Real valueL Member Length Real value in active units
GT STRUDL Parameters Used by LRFD3
V2 LRFD33 - 3 Rev T
Table LRFD33-1 (continued)
Parameters in LRFD3
Parameter Default Alternate Name Value Values
LX Member Length Real value in active unitsLY Member Length Real value in active unitsLZ Member Length Real value in active unitsMXMIN 200 (in-lb) Real value in active unitsMYMIN 200 (in-lb) Real value in active unitsMZMIN 200 (in-lb) Real value in active unitsnConnect 0 -1 -2NumBars 10 Real valuePF 10 Fraction of areaPRIDTA 10 20Print-K YES NOPrintLim NO YESREDE 10 Reduction factor for ERedFu 10 Reduction factor for FuRedFy 10 Reduction factor for FySDSWAYY YES NOSDSWAYZ YES NOSECTYPE Computed ROLLED WELDEDSFYBend 10 Real valueSLENCOMP 2000 Real valueSLENTEN 3000 Real valueSTEELGRD A36 Tables LRFD31-4 and LRFD31-5Stiff-H 00 Real value in active unitsStiff-W 00 Real value in active unitsSUMMARY NO YESTBLNAM WSHAPES9 Table LRFD31-3Tipping YES NOTRACE 4 1 2 3UNLCF Member Length Real value in active unitsUNLCFBF Member Length Real value in active unitsUNLCFTF Member Length Real value in active unitsUNLCW Member Length Real value in active unitsVALUES 1 2 3 4
Parameters Used by LRFD3 GT STRUDL
Rev T LRFD33 - 4 V2
System Parameters
PrintLim NO YES
Parameter to request to print the section limiting values for limit state andload and resistance factor design codes This parameter is applicable to the steeldesign CHECK and SELECT commands The default output from CHECK orSELECT command prints the section force values A value of lsquoYESrsquo for thisparameter indicates that the section limiting values should be printed instead ofdefault section forces
SUMMARY NO YES
Unlike the TRACE and VALUES parameters SUMMARY does not directlyproduce output during a SELECT or CHECK command Instead SUMMARYinvokes a bookkeeping system which monitors and records provision and parametervalues used at each section and loading for which the member is to be designed orchecked The two options for SUMMARY are NO or YES With the default of NOthe bookkeeping system is bypassed and no data are stored When YES is specifiedall provisions and parameters in the code Summary Description (Sections 29 and2105 of Volume 2A) are recorded Information recorded during a SELECT orCHECK can be output using the SUMMARIZE command of Section 29 of Volume2A By using SUMMARY the user is able to selectively output the same dataavailable through TRACE and VALUES at any time after the data has beenrecorded
TRACE 1 2 3 4
The TRACE parameter is used to monitor the evaluation of code provisionsduring a SELECT or CHECK command The four options are
1 - no provisions are output2 - outputs any provisions which fail3 - outputs all provisions that are considered and4 - outputs the largest value of actualallowable ratio computed
Whenever 2 or 3 is selected a heading indicating the case for which theprovision is being evaluated is output before the provision values are listed Thisheading identifies the member the profile and table being used the code and itsinternal units the loading and section location being considered and the forces
GT STRUDL Parameters Used by LRFD3
V2 LRFD33 - 5 Rev T
acting on the member for that section and loading For each provision at that sectionand loading the allowable and actual values and the actualallowable ratio areoutput Figure 72-1 of Volume 2A illustrates the information output by a TRACEvalue of 3 For a TRACE value of 2 only those provisions for which the actualexceeded the allowable are output The order in which provisions are output dependson the code being used and on the forces acting at the particular section and loadingWhen no value is specified for the parameter TRACE the default value of 4 isassumed The default output generated for the SELECT or the CHECK commandshows the member name the code name the profile name the table name theloading condition and the section location where the largest actualallowable valueoccurs the provision name corresponding to the largest actualallowable value thelargest value of actualallowable ratio computed and the internal member sectionforces at the section with the largest actualallowable ratio
VALUES 1 2 3 4
VALUES allows for the inspection of the parameters andor properties valuesused while SELECTing or CHECKing a member Each time a parameter or propertyis retrieved for use by the code or selection procedure its name and values areoutput The four options for VALUES are
1 - no parameter or property values is output2 - outputs only parameter values3 - outputs only property values and4 - outputs both parameter and property values
Unlike TRACE no headings are output when the 2 3 or 4 option ofVALUES is selected Practical use of VALUES requires simultaneous use of theTRACE 3 option An example of VALUES 2 with TRACE 3 is shown in Figure 72-2 of Volume 2A
Parameters Used by LRFD3 GT STRUDL
Rev T LRFD33 - 6 V2
Control Parameters
CODETOL 00 Percent tolerance
CODETOL allows the user to permit a reasonable tolerance in checks of thecode provisions Checks of code provisions are made by comparing the ratio ofactual to allowable against an upper limit of 10 If the limit is exceeded theprovision is failed CODETOL specifies the percentage by which the ratio mayexceed the limit and still be acceptable The general form of this comparison isshown here
With a CODETOL of 00 the default an actual over allowable of 10001would be unacceptable and marked as a fail By specifying a value for CODET-OL the user is able to account for such cases when appropriate A negative value forCODETOL would bring the upper limit below 10
FXMIN 05 lb Alternate value in active units
FXMIN specifies the smallest magnitude axial force to be considered by thecode Thus any axial force whose absolute value is below the specified value forFXMIN is treated as zero This lower limit applies to both axial tension andcompression
FYMIN 05 lb Alternate value in active units
FYMIN specifies the smallest magnitude shear force in the Y direction to beconsidered Any Y shear force that is shear through the web whose absolute valueis below the specified value of FYMIN is treated as zero
FZMIN 05 lb Alternate value in active units
FZMIN specifies the smallest magnitude shear force in the Z direction to beconsidered Any Z shear force whose absolute value is less than the specified valueof FZMIN is treated as zero
GT STRUDL Parameters Used by LRFD3
V2 LRFD33 - 7 Rev T
MXMIN 200 in-lb Alternate value in active units
MXMIN specifies the smallest magnitude X axis moment to be consideredTorsional moments about the X axis are treated as zero when their absolute valueis below MXMIN
MYMIN 200 in-lb Alternate value in active units
MYMIN specifies the smallest magnitude Y axis moment to be consideredBending moments about the Y axis are treated as zero when their absolute value isbelow MYMIN
MZMIN 200 in-lb Alternate value in active units
MZMIN specifies the smallest magnitude Z axis moment to be consideredBending moments about the Z axis are treated as zero when their absolute value isbelow MZMIN
NOTE Values given for FXMIN FYMIN FZMIN MXMIN MYMIN and MZMINshould always be greater than zero so that checks of extremely small forces andmoments are not made Forces and moments with magnitudes of 0001 and lessmay be present due to numerical limitations of the computer In most structuresforces of this magnitude are negligible when compared to the forces usually foundin a member Default values for the minimums are appropriate for mostapplications
Parameters Used by LRFD3 GT STRUDL
Rev T LRFD33 - 8 V2
Code Parameters
a 100000 in Alternate value in active units
This parameter is used to specify the clear distance between transversestiffeners This parameter is used to compute ah ratio which is used in thecomputation of the limiting shear stress The default value of 100000 inchesindicates that the shear check does not consider transverse stiffeners A userspecified value for the parameter a that causes the automatic computation of theah ratio The ah ratio is computed based on the specified value for the parametera divided by h h is defined as the total depth minus twice the flange thicknessh is assumed to be equal to the property INTYD which is the clear distancebetween the flanges (see Section LRFDE32)
Ast 00 Alternate value in active units
Parameter Ast is used to specify the transverse stiffeners area Thisparameter is used to check Appendix G4 of AISC LRFD 3rd Edition The specifiedtransverse stiffeners area is checked to see if it is smaller than the computed valuefrom Equation A-G4-1 of Appendix G4 of AISC LRFD 3rd Edition The defaultvalue of 00 indicates that the transverse stiffeners area of Appendix G4 is notchecked An alternative value in active units may be specified by the user Notethat the parameter Ast is applicable to plate girders only
avy Computed Alternate value in active units
avy is the parameter to specify the length of essentially constant shear in theY axis direction of a member This parameter is used to check the Y directionshear of a pipe cross-section This parameter is similar to the variable a in theEquation 52-2 of the AISC LRFD HSS specification in the Section 162 of theLRFD Third Edition (96) The default is computed as the effective member lengthSee the LY parameter for a description of the effective length An alternative valuein active units may be specified by the user Note that the parameter avy isapplicable to pipes cross-sections only
GT STRUDL Parameters Used by LRFD3
V2 LRFD33 - 9 Rev T
avz Computed Alternate value in active units
avz is the parameter to specify the length of essentially constant shear in theZ axis direction of a member This parameter is used to check the Z direction shearof a pipe cross-section This parameter is similar to the variable a in the Equation52-2 of the AISC LRFD HSS specification in the Section 162 of the LRFD ThirdEdition (96) The default is computed as the effective member length See the LZparameter for a description of the effective length An alternative value in activeunits may be specified by the user Note that the parameter avz is applicable topipes cross-sections only
CantiMem NO YES
This parameter indicates that a member or a physical member which is partof a cantilever truss should be considered as a cantilever beam in the K-factorcomputation This parameter can be used in special cases when the program cannot automatically detect that the beam connected to the column is a cantilever Thespecial case when this parameter may be used is when the beam that is connectedto the column is part of a cantilever truss system and the program automatically isnot able to detect that the beam should be considered as a cantilever beam in theK-factor computation Keep in mind that only true cantilever members or physicalmembers are detected automatically A value of YES for this parameter indicatesthat the member of physical member is cantilever
CB Computed Alternate value
CB is the coefficient Cb used in Section F12a of the 1999 AISC LRFD ThirdEdition Specification (96) Cb is a modification factor for non-uniform momentdiagram when both ends of the beam segment are braced This coefficientincreases the limiting nominal compressive flexural strength when a momentgradient exists over the unbraced length of the compression flange
LRFD Eq F1-3
where
Mmax = absolute value of maximum moment in the unbraced segmentabout the Z axis kip-in (N-mm)
MA = absolute value of moment at quarter point of the unbraced segment
Parameters Used by LRFD3 GT STRUDL
Rev T LRFD33 - 10 V2
about the Z axis kip-in (N-mm)MB = absolute value of moment at centerline of the unbraced beam
segment about the Z axis kip-in (N-mm)MC = absolute value of moment at three-quarter point of the unbraced
beam segment about the Z axis kip-in (N-mm)
When computing the default value of Cb the compression flange is assumedto be laterally supported (ie braced) only at the member ends In cases where theactual unbraced length is different than the eccentric member length (start to endof the member) the user should specify a value for parameter CB A value of 10is always conservative and may be used in either of the preceding cases
Cby Computed Alternate value
Cby is the coefficient Cb used in Section F12a of the 1999 AISC LRFDThird Edition Specification (96) This parameter is applicable to rectangularhollow structural section HSS (structural tube) cross-section only Cby is amodification factor for non-uniform moment diagram when both ends of the beamsegment are braced This coefficient increases the limiting nominal compressiveflexural strength when a moment gradient exists over the unbraced length of thecompression flange Cby is used for the rectangular hollow structural section HSS(structural tube) cross-sections under Y axis bending
LRFD Eq F1-3
where
Mmax = absolute value of maximum moment in the unbraced segmentabout the Y axis kip-in (N-mm)
MA = absolute value of moment at quarter point of the unbraced segmentabout the Y axis kip-in (N-mm)
MB = absolute value of moment at centerline of the unbraced beamsegment about the Y axis kip-in (N-mm)
MC = absolute value of moment at three-quarter point of the unbracedbeam segment about the Y axis kip-in (N-mm)
When computing the default value of Cby the compression web is assumedto be laterally supported (ie braced) only at the member ends In cases where theactual unbraced length is different than the eccentric member length (start to end
GT STRUDL Parameters Used by LRFD3
V2 LRFD33 - 11 Rev T
of the member) the user should specify a value for parameter Cby A value of 10is always conservative and may be used in either of the preceding cases
CODE Required
The CODE parameter indicates the code procedure which should be used fordesigning or checking a member A value of LRFD3 must be specified for thisparameter to check code based on 1999 AISC LRFD Third Edition LRFD3design or code check is based on the AISC LRFD Load and Resistance FactorDesign Specification for Structural Steel Buildings adopted December 27 1999with errata incorporated as of September 4 2001 (96)
COMPK NO YES KY KZ
The COMPK parameter is used to specify how the values of the effectivelength parameters KY and KZ are defined The default value of NO indicates thatthe values of KY and KZ are either specified by the user or taken as 10 by default
The value of YES indicates that the values of KY and KZ are to be computedby GTSTRUDL in the member selection and code check procedures (SELECT orCHECK command) The K-factors computed by GTSTRUDL is based on theAISC (American Institute of Steel Construction) guidelines If the value ofCOMPK is NO the values of KY and KZ are taken as either specified by the useror as 10 by default
The value of KY or KZ for the parameter COMPK indicates that only thespecified effective length factor should be computed Refer to Section 22 ofVolume 2A for more discussion of the effective length factor computation
ConnType WELDED SNUG
Type of the intermediate connectors that are used for double angle Choicesare SNUG and WELDED
SNUG = intermediate connectors that are snug-tight boltedWELDED = intermediate connectors that are welded or fully tensioned
bolted This is the default
Note that the parameter ConnType is applicable to double angles only
Parameters Used by LRFD3 GT STRUDL
Rev T LRFD33 - 12 V2
Dstiff 24 10 18
This parameter is used to specify the factor D that is used in the Equation A-G4-1 of Appendix G4 of AISC LRFD 3rd Edition (96) A default value of 24 forsingle plate stiffeners is assumed The value of factor D (parameter Dstiff) in theEquation A-G4-1 is dependent on the type of transverse stiffeners used in a plategirder Alternate values are as follows
10 = for stiffeners in pairs This is the default value when the specifiedvalue for the parameter NumBars is greater than 1
18 = for single angle stiffeners24 = for single plate stiffeners This is the default value when the
specified value for the parameter NumBars is equal to 1
Note that the parameter Dstiff is applicable to plate girders only
FRLX 10 Fraction of member length
FRLX specifies the unbraced length of torsional buckling LX as a fractionof the members effective length FRLX may be less than or greater than 10 Thisoption works only when LX is computed
FRLY 10 Fraction of member length
FRLY specifies the unbraced length for buckling about the Y axis LY as afraction of the members effective length FRLY may be less than or greater than10 This option works only when LY is computed
FRLZ 10 Fraction of member length
FRLZ specifies the unbraced length for buckling about the Z axis LZ as afraction of the members effective length FRLZ may be less than or greater than10 This option works only when LZ is computed
FRUNLCF 10 Fraction of member length
FRUNLCF specifies the unbraced length of the compression flange UNLCFas a fraction of the members effective length FRUNLCF may be less than orgreater than 10 This option works only when UNLCF is computed
GT STRUDL Parameters Used by LRFD3
V2 LRFD33 - 13 Rev T
FRUNLCW 10 Fraction of member length
FRUNLCW specifies the unbraced length of the compression web UNLCWas a fraction of the members effective length FRUNLCW may be less than orgreater than 10 This parameter works only when UNLCW is computed Notethat the parameter FRUNLCW is applicable to rectangular hollow structuralsection HSS (structural tube) only
Fu Computed Alternate value in active units
The minimum tensile strength of a member may be specified via Fu WhenFu is specified the STEELGRD and profile GRPNUM are not considered and thevalue of Fu remains constant for the member
Fy Computed Alternate value in active units
Fy may be used to specify the yield strength of a member rather than havingit computed from STEELGRD and GRPNUM When Fy is specified for amember its value remains constant irrespective of profile size under considerationThe value of STEELGRD is not considered for such members even if it wasspecified
Fyf Fy Alternate value in active units
Parameter Fyf may be used to specify the yield strength of the flange Whenparameter Fyf is not specified the value for this parameter is assumed to be equalto the parameter Fy When a value is specified for this parameter the member isassumed to be hybrid cross-section An alternative value in active units may bespecified by the user
Fyst Fy Alternate value in active units
Parameter Fyst may be used to specify the yield strength of the plate girderstransverse stiffeners material When parameter Fyst is not specified the value forthis parameter is assumed to be equal to the parameter Fy This parameter is usedto check the transverse stiffeners of the plate girder An alternative value in activeunits may be specified by the user Note that the parameter Fyst is applicable toplate girders only
Parameters Used by LRFD3 GT STRUDL
Rev T LRFD33 - 14 V2
Fyw Fy Alternate value in active units
Parameter Fyw may be used to specify the yield strength of the web Whenparameter Fyw is not specified the value for this parameter is assumed to be equalto the parameter Fy When a value is specified for this parameter the member isassumed to be hybrid cross-section An alternative value in active units may bespecified by the user
GAY Computed Alternative value
GAY is the G-factor at the start joint of the member GAY is used in thecalculation of the effective length factor KY (see parameter COMPK and KY)
GAZ Computed Alternative value
GAZ is the G-factor at the start joint of the member GAZ is used in thecalculation of the effective length factor KZ (see parameter COMPK and KZ)
GBY Computed Alternative value
GBY is the G-factor at the end joint of the member GBY is used in thecalculation of the effective length factor KY (see parameter COMPK and KY)
GBZ Computed Alternative value
GBZ is the G-factor at the end joint of the member GBZ is used in thecalculation of the effective length factor KZ (see parameter COMPK and KZ)
Ist 00 Alternate value in active units
Parameter Ist is used to specify the transverse stiffeners moment of inertiaThis parameter is used to check Appendix F23 of ASIC LRFD 3rd Edition for therequired transverse stiffeners moment of inertia The default value of 00 indicatesthat the transverse stiffeners moment of inertia according to Appendix F23 ofAISC LRFD 3rd Edition is not checked An alternative value in active units maybe specified by the user Note that the parameter Ist is applicable to plate girdersonly
GT STRUDL Parameters Used by LRFD3
V2 LRFD33 - 15 Rev T
K 10 Alternate value
Effective length factor for an individual component (single angle) Thisparameter is used to design a number of connectors and to check the connectorspacing (Section E42 of the AISC LRFD 3rd Edition) Note that the parameter lsquoKrsquois applicable to double angles only
KX 10 Alternative value
KX is the effective length factor for torsional buckling This parameter isused in the computation of flexural-torsional buckling A default value of 10 isassumed An alternate value may be specified by the user
KY 10 Alternative value computed
KY is the effective length factor used for buckling about the local memberY axis (Figure LRFD33-1) and its value is determined according to the followingprovisions
(1) KY is taken either as 10 by default or as the alternative value specified bythe user if the value of the COMPK parameter is equal to NO
(2) KY is computed if the value of COMPK is equal to YES or KY Refer toSection 22 of Volume 2A for more discussion and an example of theeffective length factor computation
KZ 10 Alternative value computed
KZ is the effective length factor used for buckling about the local member Zaxis (Figure LRFD33-1) and its value is determined according to the followingprovisions
(1) KZ is taken either as 10 by default or as the alternative value specified bythe user if the value of the COMPK parameter is equal to NO
(2) KZ is computed if the value of COMPK is equal to YES or KZ Refer toSection 22 of Volume 2A for more discussion and an example of theeffective length factor computation
Parameters Used by LRFD3 GT STRUDL
Rev T LRFD33 - 16 V2
Figure LRFD33-1 Local Axis Buckling
GT STRUDL Parameters Used by LRFD3
V2 LRFD33 - 17 Rev T
L Computed Alternate value in active units
Actual physical member length is used to design a number of connectors andto check connector spacing (Section E42 of the AISC LRFD 3rd Edition) and alsoused in the computation of the modified column slenderness (KLr)m (Section E41of the AISC LRFD 3rd Edition) This parameter is used to compute the distancebetween connectors a = L(n+1) where lsquoarsquo is the distance between connectors lsquoLrsquois the member length and lsquonrsquo is the number of connectors The default iscomputed as the length of the member Note that the parameter lsquoLrsquo is applicableto double angles only
LX Computed Alternate value in active units
LX is the distance between torsional buckling restraints This parameter isused in the computation of flexural-torsional buckling The default is computedas the effective member length times the value of the FRLX parameter See theLY parameter below for a description of the effective length An alternate valuein the active units may be specified by the user
LY Computed Alternate value in active units
LY specifies the unbraced length for buckling about the Y axis as shown inFigure LRFD33-1 The default is computed as the effective member length timesthe value of the FRLY parameter The effective length of a member is the joint-to-joint distance unless eccentricities andor end joint sizes are given Wheneccentricities are given the eccentric start-to-end length of the member is usedFor end joint sizes the end joint size at both ends is subtracted from the effectivelength which would have been used LY may be specified larger or smaller thanthe members effective length and no comparisons are made between the two SeeSection 218 of Volume 1 for a discussion of member eccentricities and end jointsizes
LZ Computed Alternate value in active units
LZ specifies the unbraced length for buckling about the Z axis as shown inFigure LRFD33-1 The default is computed as the effective member length timesthe value of the FRLZ parameter See the LY parameter above for a descriptionof the effective length
Parameters Used by LRFD3 GT STRUDL
Rev T LRFD33 - 18 V2
nConnect 0 Alternate value
Number of connectors between individual angles The user specified valueis used during code check When the SELECT MEMBER (design) is requestedthe user specified value is used unless more connectors are required If thedesigned number of connectors are larger than the user specified value thecomputed number of connectors are used and printed after the SELECT MEMBERresult The default value of zero indicates that the angles are connected at the endsonly Following are additional options that you can specify for this parameter
0 = angles are connected at the ends of the memberndash1 = requesting the number of connectors to be computed during code
checkndash2 = bypass modified column slenderness equations This will bypass the
check for the Section E41 of the AISC LRFD Third Edition
Note that the parameter nConnect is applicable to double angles only
NumBars 10 Alternate value
Parameter to specify a number of single plate stiffeners The default valuefor this parameter indicates one (1) single plate stiffener An alternative value maybe specified by the user Note that the parameter NumBars is applicable to plategirders only
PF 10 Fraction of cross-sectional area
PF is used to compute the net area for members subject to axial tension Byspecifying a value for PF the user is able to account for holes which make the netarea less than the full cross-sectional area
Print-K YES NO
Parameter to print the computed K-factor values after the default code checkor select command output (TRACE 4 output) The default value of lsquoYESrsquo for thisparameter indicates that the computed K-factor values should be printed after thecode check or select command output The column names attached to the start andend of the code checked member is also printed This printed information allowsthe user to inspect the automatic detection of the columns attached to the start andend of the designed member A value of lsquoNOrsquo indicates that K-factor values andthe names of the attached columns to the start and end of the designed membershould not be printed
GT STRUDL Parameters Used by LRFD3
V2 LRFD33 - 19 Rev T
REDE 10 Reduction factor for the constant E
The modulus of elasticity for a member is multiplied by this factor before usein the design equations of the LRFD3 code The value of E specified in theCONSTANTS command is not altered when used in analysis commands
RedFu 10 Reduction factor for Fu
RedFu allows a user to account for changes in the minimum tensile strengthFu of a member such as those which occur at high temperatures RedFu ismultiplied by Fu to give the value used for minimum tensile strength
RedFy 10 Reduction factor for Fy
The parameter RedFy is a reduction factor for the yield strength Fy of amember This parameter is intended to reflect the change in yield strength whichoccurs at higher temperatures An alternate use for RedFy would be to introducean additional factor of safety into the design equations The yield strength used inthe provision is equal to RedFy multiplied by Fy (RedFy times Fy)
SDSWAYY YES NO
SDSWAYY indicates the presence of sidesway about the Y axis of themember A value of YES indicates that sidesway is permitted this is often referredto as an unbraced frame For braced frames in which sidesway is prevented avalue of NO should be specified Figure LRFD33-2 illustrates the direction ofsway relative to the column orientation
SDSWAYZ YES NO
SDSWAYZ indicates the presence of sidesway about the Z axis of themember A value of YES indicates that sidesway is permitted this is often referredto as an unbraced frame For braced frames in which sidesway is prevented avalue of NO should be specified Figure LRFD33-2 illustrates the direction ofsway relative to the column orientation
Parameters Used by LRFD3 GT STRUDL
Rev T LRFD33 - 20 V2
Figure LRFD33-2 SIDESWAY Conditions
GT STRUDL Parameters Used by LRFD3
V2 LRFD33 - 21 Rev T
SECTYPE Computed ROLLED WELDED
This parameter defines the type of a cross-section specified in the structuralmodel This parameter is used to compute the value of Fr Fr is the compressiveresidual stress in the flange The value of ROLLED indicates that the members arehot rolled cross-sections The compressive residual stress Fr is equal to 10 ksi formembers that are indicated as rolled cross-sections The value of WELDED forthe parameter SECTYPE indicates that the members are welded or cold-formedcross-sections The compressive residual stress Fr is equal to 165 ksi for membersthat are indicated as welded cross-sections The default value for SECTYPEparameter indicates that the plate girders are assumed to be welded and all othercross-sections are assumed to be rolled
SFYBend 10 Alternate value
Parameter to specify safety factor for the computation of the limit state of Yaxis (minor axis) bending of the tee and double angle sections Note that theparameter SFYBend is applicable to tees and double angles only
SLENCOMP Computed Alternate value
SLENCOMP is the maximum permissible slenderness ratio (KLr) for amember subjected to the axial compression The default is computed as a value of2000 for compression members An alternate value may be specified by the user
SLENTEN Computed Alternate value
SLENTEN is the maximum permissible slenderness ratio (KLr) for membersubjected to the axial tension The default is computed as a value of 3000 fortension members An alternate value maybe specified by the user
STEELGRD A36 Value from Tables LRFD31-4 and LRFD31-5
STEELGRD specifies the grade of steel from which a member is to be madeUsing the value of STEELGRD the yield strength (Fy) can be correctlydetermined
Parameters Used by LRFD3 GT STRUDL
Rev T LRFD33 - 22 V2
Stiff-H 00 Alternate value in active units
Parameter Stiff-H is used to specify the single plate stiffeners cross-sectionsheight Parameters Stiff-H Stiff-W and NumBars are used for the automaticcomputation of the parameters Ast and Ist is based on the rectangular barstiffeners geometry If the transverse stiffeners are not rectangular bar parametersAst and Ist should be specified An alternative value may be specified by theuser Note that the parameter Stiff-H is applicable to plate girders only
Stiff-W 00 Alternate value in active units
Parameter Stiff-W is used to specify the single plate stiffeners cross-sectionswidth Parameters Stiff-H Stiff-W and NumBars are used for the automaticcomputation of the parameters Ast and Ist The automatic computation of theparameters of the parameters Ast and Ist is based on the rectangular barstiffeners geometry If the transverse stiffeners are not rectangular bar parametersAst and Ist should be specified An alternative value may be specified by theuser Note that the parameter Stiff-W is applicable to plate girders only
Tipping YES NO
This is the parameter indicating that the tipping effect should be consideredWhen the load is applied to the top flange of the channel and the flange is notbraced there is a tipping effect that reduces the critical moment A value of YESfor this parameter indicates that the flange is unbraced and the flange is loaded assuch that causes tipping effect In this case the reduced critical moment may beconservatively approximated by setting the warping buckling factor X2 equal tozero A value of NO indicates that the tipping effect does not happen and thewarping buckling factor is computed based on the Equation F1-9 of the AISCLRFD Third Edition
UNLCF Computed Alternate value in active units
UNLCF specifies the unbraced length of the compression flange which isused in computing the allowable bending stress of a member The maximumdistance between points of adequate lateral support for the compression flangeshould be used The default is computed as the effective length of the membertimes the value of the FRUNLCF parameter Refer to the parameter LY for adiscussion of a members effective length
GT STRUDL Parameters Used by LRFD3
V2 LRFD33 - 23 Rev T
UNLCFBF Computed Alternate value in active units
UNLCFBF specifies the unbraced length of the compression flange for thebottom flange which is used in computing the allowable bending stress of amember Bottom flange is defined as the flange in the local negative Y axisdirection of a cross section as shown in Figure LRFD33-4 UNLCFBF is usedwhen negative strong axis bending (negative MZ) is acting on the member whichcauses compression on the bottom flange The maximum distance between pointsof adequate lateral support for the bottom compression flange should be usedWhen an alternate value for this parameter has not been specified the value for theparameter UNLCF is used See parameter UNLCF for the default treatment of theparameter UNLCFBF
UNLCFTF Computed Alternate value in active units
UNLCFTF specifies the unbraced length of the compression flange for thetop flange which is used in computing the allowable bending stress of a memberTop flange is defined as the flange in the local positive Y axis direction of a crosssection as shown in Figure LRFD33-4 UNLCFTF is used when positive strongaxis bending (positive MZ) is acting on the member which causes compression onthe top flange The maximum distance between points of adequate lateral supportfor the top compression flange should be used When an alternate value for thisparameter has not been specified the value for the parameter UNLCF is used Seeparameter UNLCF for the default treatment of the parameter UNLCFTF
UNLCW Computed Alternate value in active units
UNLCW specifies the unbraced length of the compression web which isused in computing the limiting bending capacity of a member The maximumdistance between points of adequate lateral support for the compression web shouldbe used The default is computed as the effective length of the member times thevalue of the FRUNLCW parameter Refer to the parameter LY for a discussion ofa members effective length An alternative value in active units may be specifiedby the user Note that the parameter UNLCW is applicable to rectangular hollowstructural sections HSS (structural tubes) only
Parameters Used by LRFD3 GT STRUDL
Rev T LRFD33 - 24 V2
Figure LRFD33-4 Unbraced length of the compression flange forthe TOP and BOTTOM flange
GT STRUDL APPENDIX A References
V2 LRFD3 Appendix A - 1 Rev T
APPENDIX A References
1 Connor Jerome J Analysis of Structural Member Systems The Ronald PressCompany New York 1976
2 ICES Programmers Reference Manual 2nd Ed Edited by W Anthony Dillon CivilEngineering Systems Laboratory Massachusetts Institute of TechnologyCambridge Mass Research Report No R71-33 August 1971
3 ICES System General Description Edited by Daniel Roos Civil EngineeringSystems Laboratory Massachusetts Institute of Technology Cambridge MassResearch Report No R67-49 September 1967
4 ICES Subsystem Development Primer Civil Engineering Systems LaboratoryMassachusetts Institute of Technology Cambridge Mass Research Report NoR68-56 May 1968
5 Logcher Robert D et al ICES STRUDL-II The Structural Design LanguageEngineering Users Manual Volume 1 Civil Engineering Systems LaboratoryMassachusetts Institute of Technology Cambridge Mass Research Report NoR68-91 November 1968
6 MIT ICES360 STRUDL II Documentation for Stiffness Analysis and Steel MemberSelection Civil Engineering Systems Laboratory Massachusetts Institute ofTechnology Cambridge Mass January 1972
7 Roos Daniel ICES System Design 2nd Ed Cambridge Mass The MIT Press1967
8 Schumacher Betsy An Introduction to ICES Civil Engineering Systems LaboratoryMassachusetts Institute of Technology Cambridge Mass Research Report NoR67-47 September 1967
9 Standard Specification for Zinc-Coated Steel Structural Strand ASTM A506-68January 1968
10 The ICES STRUDL Swap Enhancements ICES Distribution Agency PO Box3956 San Francisco California 94119
11 ICES JOURNAL ICES Users Group Inc Frederick E Hajjar Editor PO Box231 Worcester Mass 01613
APPENDIX A References GT STRUDL
Rev T LRFD3 Appendix A - 2 V 2
12 Logcher Robert D et al ICES STRUDL-II The Structural Design LanguageEngineering Users Manual Volume 2 Civil Engineering Systems LaboratoryMassachusetts Institute of Technology Cambridge Mass Research Report NoR70-77 2nd Edition December 1973
13 ICES STRUDL-II The Structural Design Language Engineering Users ManualVolume 3 Structures Division and Civil Engineering Systems LaboratoryMassachusetts Institute of Technology Cambridge Mass June 1970
14 Logcher Robert D et al ICES TABLE-I An ICES File Storage SubsystemEngineering Users Manual Civil Engineering Systems Laboratory MassachusettsInstitute of Technology Cambridge Mass Research Report No R67-58 September1967
15 Manual of STEEL CONSTRUCTION Sixth Edition American Institute of SteelConstruction Inc New York 1963
16 Manual of STEEL CONSTRUCTION Seventh Edition American Institute of SteelConstruction Inc New York 1969
17 King Reno C Piping Handbook 5th ed page 4-51 McGraw-Hill Book Company1967
18 GTICES TOPOLOGY Users Manual School of Civil Engineering Georgia Instituteof Technology Atlanta Georgia 1976
19 Zienkiewicz O C The Finite Element Method in Engineering Science McGraw-Hill London Third Edition 1977
20 Connor J J and Will G T Triangular Flat Plate Bending Element ReportTR68-3 MIT Department of Civil Engineering February 1968
21 Connor J J and Will G T Computer-Aided Teaching of the Finite ElementDisplacement Method Report 69-23 MIT Department of Civil EngineeringFebruary 1969
22 Ergatoudis I Irons B M and Zienkiewicz O C Curved IsoparametricQuadrilateral Elements for Finite Element Analysis Int J Solids and Structures4 1968
23 Aparicia L E and Connor J J Isoparametric Finite Element DisplacementModels Research Report R70-39 MIT Department of Civil Engineering July1970
GT STRUDL APPENDIX A References
V2 LRFD3 Appendix A - 3 Rev T
24 Britten S S and Connor J J A New Family of Finite Elements Research ReportR71-14 MIT Department of Civil Engineering February 1971
25 Aparicia L E Finite Element Implementation for the Structural Design LanguageM S Thesis MIT Department of Civil Engineering September 1969
26 Felippa C D Refined Finite Element Analysis of Linear and Nonlinear TwoDimensional Structures SESM Report 66-22 University of California at Berkeley1966
27 Caramanlian C Selby K A and Will G T Plane Stress Formulation in FiniteElement Method Publication 76-06 University of Toronto Department of CivilEngineering June 1976
28 Kok A W M and Vrijman C F A New Family of Reissner-ElementsDepartment of Civil Engineering Delft University of Technology Netherlands tobe published
29 Adini A and Clough R W Analysis of Plate Bending by the Finite ElementMethod Report submitted to the National Science Foundation Grant G7337 1960
30 Clough R W Comparison of Three Dimensional Finite Elements Proceedingsof the Symposium on Application of Finite Element Methods in Civil EngineeringAmerican Society of Civil Engineers Nashville Tennessee November 1969
31 Szilard R Theory and Analysis of Plates Classical and Numerical MethodsPrentice Hall Englewood Cliffs New Jersey 1974
32 Arena J R et al Guide for Design of Steel Transmission Towers ASCE - Manualsand Reports on Engineering Practice - No 52 1971
33 Manual of STEEL CONSTRUCTION Eighth Edition American Institute of SteelConstruction Inc New York 1980
34 Dimensions and Properties New W HP and WT Shapes American Institute of SteelConstruction Inc New York 1978
35 Guide to Stability Design Criteria for Metal Structures Third Edition Edited byBruce G Johnston John Wiley and Sons Inc 1976
36 McGuire William Steel Structures Prentice-Hall Inc Englewood Cliffs NewJersey 1968
APPENDIX A References GT STRUDL
Rev T LRFD3 Appendix A - 4 V 2
37 Salmon Charles G and Johnson John E Steel Structures Design and BehaviorInternational Textbook Company 1971
38 Marcus Samuel H Basics of Structural Steel Design Reston Publishing CompanyInc Reston Virginia 1977
39 Adams P F Krentz H A and Kulak G L Limit States Design in StructuralSteel Canadian Institute of Steel Construction 1977
40 Limit States Design Steel Manual First Edition Edited by M I Gilmor CanadianInstitute of Steel Construction 1977
41 Gilmor Michael I Implementation of CSA S16-1969 in ICES Subsystem STRUDLCanadian Institute of Steel Construction 1970
42 Gilmore Michael I and Selby Kenneth A STRUDL II - CSA S16 Users ManualCanadian Institute of Steel Construction 1970
43 Clough R W and Penzien J Dynamics of Structures McGraw-Hill Inc 1975
44 Biggs J M Structural Dynamics McGraw-Hill Inc 1964
45 Timoshenko S P Young D H and Weaver W Vibration Problems inEngineering John Wiley and Sons 1974
46 Bathe K J and Wilson E L Numerical Methods in Finite Element AnalysisPrentice 1976
47 Wilkinson J H The Algebraic Eigenvalue Problem Oxford Univeristy Press 1965
48 Rosen R and Rubinstein M F Dynamic Analysis by Matrix DecompositionJournal of the Engineering Mechanics Division American Society of CivilEngineers April 1968
49 Newman Malcolm and Flanagan Paul Eigenvalue Extraction in NASTRAN by theTridiagonal Reduction (FEER) Method NASA CR-2731 1971
50 Cullum J A and Willoughby R A Fast Modal Analysis of Large Sparse butUnstructured Symmetric Matrices Proceedings of the 17th IEEE Conference onDecision and Control San Diego California January 1979
51 Paige C C Computational Variants of the Lanczos Method for the EigenproblemJ INST MATH APPL 10 373-381
GT STRUDL APPENDIX A References
V2 LRFD3 Appendix A - 5 Rev T
52 API Recommended Practice for Planning Designing and Constructing FixedOffshore Platforms Eleventh Edition January 1980
53 Wong Lung-Chun Implementation of AISC Design for W shapes Channels andTees in GTSTRUDL GTICES Systems Laboratory School of Civil EngineeringAtlanta Georgia unpublished research report March 1980
54 ASME Boiler and Pressure Vessel Code Section III Rules for Construction ofNuclear Power Plant Components Division 1 - Subsection NF Component SupportsJuly 1 1977
55 Heins C P and Seaburg P A Torsional Analysis of Rolled Steel SectionsBethlehem Steel Corporation 1963
56 Heins C P Bending and Torsional Design in Structural Members LexingtonBooks 1975
57 Megson T H G Linear Analysis of Thin-Walled Elastic Structures John Wileyand Sons Inc 1974
58 Timoshenko S P and Goodier J N Theory of Elasticity McGraw-Hill 1970
59 Timoshenko S P and Goodier J N Theory of Elastic Stability McGraw-Hill1961
60 Wong L C and Thurmond M W Warping in Open and Closed Sections GTICESSystems Laboratory School of Civil Engineering Atlanta Georgia June 1981
61 Der Kiureghian Armen A Response Spectrum Method for Random VibrationsReport No VCBEERC-8015 Earthquake Engineering Research Center Universityof California Berkeley June 1980
62 Gibbs N E Poole W G Jr and Stockmeyer P K An Algorithm for Reducingthe Bandwidth and Profile of a Sparse Matrix SIAM Journal Numerical AnalysisVol 13 No 2 April 1976
63 Cuthill E and McKee J Reducing the Bandwidth of Sparse SymmetricMatrices Proceedings of the 24th National Conference Association for ComputingMachinery 1969
64 Combining Modal Responses and Spatial Components in Seismic ResponseAnalysis Regulatory Guide US Nuclear Regulatory Commission Office ofStandards Development Section 192 February 1976
APPENDIX A References GT STRUDL
Rev T LRFD3 Appendix A - 6 V 2
65 Blodgett Omer W Design of Welded Structures The James F Lincoln ArcWelding Foundation Cleveland Ohio June 1966
66 Mander J B Priestley M J N and Park R ldquoTheoretical Stress-Strain Model forConfined Concreterdquo Journal of Structural Engineering Vol 114 No 8 August1988
67 Structural Welding Code - Steel (AWS D11-83) American Welding SocietyMiami Florida December 1983
68 ASME Boiler and Pressure Vessel Code Section III Rules for Construction ofNuclear Power Plant Components Division 1 - Subsection NF Component SupportsJuly 1 1983
69 Development of Floor Design Response Spectra for Seismic Design ofFloor-Supported Equipment or Components Regulatory Guide US NuclearRegulatory Commision Office of Standards Development Section 1122 February1978
70 Hughes T Cohen M The Heterosis Finite Element for Plate BendingComputers and Structures Vol 9 1978 pp 445-450
71 ASCE 4-98 Seismic Analysis of Safety-Related Nuclear Structures and CommentaryAmerican Society of Civil Engineers New York New York 2000
72 Manual of Steel Construction Allowable Stress Design Ninth Edition AmericanInstitute of Steel Construction Inc Chicago Illinois 1989
73 Structural Welding Code - Steel ANSIAWS D11-90 American National StandardsInstitute American Welding Society Miami Florida 1990
74 Guide for Design of Steel Transmission Towers Second Edition ASCE Manuals andReports on Engineering Practice No 52 New York New York 1988
75 Structural Welding Code - Steel ANSIAWS DI1-94 American National StandardsInstitute American Welding Society Miami Florida 1994
76 Cold-Formed Steel Design Manual American Iron and Steel Institute WashingtonDC 1989
77 UNISTRUT Corporation Notes 1994 Notes covering a copy of UNISTRUTSection Properties UNISTRUT Northern Area 1500 Greenleaf Elk Grove VillageIL 60007 January 7 1994
GT STRUDL APPENDIX A References
V2 LRFD3 Appendix A - 7 Rev T
78 General Engineering Catalog UNISTRUT Metal Framing North American EditionNo 12 UNISTRUT Corporation 35660 Clinton Street Wayne Michigan 481841993
79 Structural Use of Steelwork in Building British Standards Institution BS 5950 Part1 1990 Part 1 Code of Practice for Design in simple continuous Construction HotRolled Sections London England 1990
80 Manual of Steel Construction Load amp Resistance Factor Design First EditionAmerican Institute of Steel Construction Inc Chicago Illinois 1986
81 Manual of Steel Construction Load amp Resistance Factor Design Volume I SecondEdition American Institute of Steel Construction Inc Chicago Illinois 1993
82 Steelwork Design Guide to BS 5950 Part 1 1990 Volume 1 Section PropertiesMember Capacities 4th Edition Published by The Steel Construction Institute inassociation with the British Constructional Steelwork Association Limited BritishSteel PIC Berkshire England 1996
83 Metric Properties of Structural Shapes with Dimensions According to ASTM A6MAmerican Institute of Steel Construction Inc Chicago Illinois 1992
84 Batterman RH Computer Program for Cable Sag and Tension Calculations Engineering Design Division ALCOA Research Laboratories Aluminum Companyof America
85 Guidelines for Electrical Transmission Line Structural Loading ASCE Manuals andReports on Engineering Practice No 74 American Society of Civil Engineers NewYork New York 1991
86 Minimum Design Loads for Buildings and Other Structures ASCE 7-95 AmericanSociety of Civil Engineers New York New York 1996
87 Peyrot Alain PLS-CADD Users Manuals PLS-CADD Version 30 Power LineSystems Inc 1995
88 Balan Toader A Filippou Filip C and Popov Egor P ldquoHysteretic Model ofOrdinary and High Strength Reinforcing Steelrdquo Journal of Structural EngineeringVol 124 No 3 March 1998
89 Handbook of Steel Construction Seventh Edition Canadian Institute of SteelConstruction Ontario Canada 1997
APPENDIX A References GT STRUDL
Rev T LRFD3 Appendix A - 8 V 2
90 Eurocode 3 Design of steel structures Part 11 General rules and rules forbuildings (together with United Kingdom National Application Document) DDENV 1993-1-11992 British Standards Institution
91 STAHLBAU-PROFILE 21 Auflage uumlberarbeiteter Nachdruck 1997
92 Indian Standard CODE OF PRACTICE FOR GENERAL CONSTRUCTION INSTEEL Second Revision IS800-1984 New Delhi December 1995
93 Indian Standard DIMENSIONS FOR HOT ROLLED STEEL BEAM COLUMNCHANNEL AND ANGLE SECTIONS Third Revision IS 8081989 New DelhiSeptember 1989
94 AISC LRFD Specification for the Design of Steel Hollow Structural Sections April15 1997 American Institute of Steel Construction Inc Chicago Illinois 1997
95 Structural Use of Steelwork in Building Part 1 Code of practice for design of rolledand welded sections British Standard BS 5950-1 2000 London England May2001
96 Manual of Steel Construction AISC Load and Resistance Factor Design ThirdEdition American Institute of Steel Construction Inc Chicago Illinois 1999
97 1997 Uniform Building Code Volume 2 Structural Engineering Design ProvisionsInternational Conference of Building Officials Whittier California April 1997
GT STRUDL Appendix B Use of GTTABLE
V2 LRFD3 Appendix B - 1 Rev T
Appendix B Use of GTTABLE
This appendix has been discussed in detail in Volume 2A Please see Appendix Bof Volume 2A for a summary of the Use of GTTABLE
Appendix B Use of GTTABLE GT STRUDL
Rev T LRFD3 Appendix B - 2 V 2
This page intentionally left blank
GT STRUDL Appendix C GTSTRUDL Tables of Steel Profiles
V2 LRFD3 Appendix C - 1 Rev T
Appendix C GTSTRUDL Tables of Steel Profiles
This appendix has been discussed in detail in Volume 2A Please see Appendix Cof Volume 2A for a summary of the major steel profile (section) tables provided withGTSTRUDL
Appendix C GTSTRUDL Tables of Steel Profiles GT STRUDL
Rev T LRFD3 Appendix C - 2 V 2
End of Document
LRFD3 Steel Design Code and Parameters GT STRUDL
52 - 2
Figure LRFD31-1 Local Axes for Design with LRFD3
GT STRUDL LRFD3 Steel Design Code and Parameters
52 - 3
Figure LRFD31-1 Local Axes for Design with LRFD3 (continued)
LRFD3 Steel Design Code and Parameters GT STRUDL
52 - 4
Figure LRFD31-1 Local Axes for Design with LRFD3 (Continued)
GT STRUDL LRFD3 Steel Design Code and Parameters
52 - 5
The following assumptions are made throughout the LRFD3 code
1 Open cross-sections (I shapes channels single angles double angles teesbars and plate girders) are normally not used in situations whereinsignificant torsional moments must be resisted by the member Torsionalstresses are usually small for open cross-sections when compared to axial andbending stresses and may be neglected No checks are made for torsion inopen cross-sections (I shapes channels single angles double angles teesbars and plate girders) The designer is reminded to check the torsionalstresses for open cross-sections (I shape channels single angles doubleangles tees bars and plate girders) whenever they become significant
2 Torsional stresses are checked for round HSS (pipes) rectangular and squareHSS (structural tubes) based on the Section 61 on Page 162-8 of the AISCLRFD Third Edition Combined torsion shear flexure andor axial forcesare also checked for round HSS (pipes) rectangular and square HSS(structural tubes) based on the Section 72 on Page 162-10 of the AISCLRFD Third Edition Closed cross-sections (HSS) are frequently used insituations wherein significant torsional moments must be resisted by themembers Generally the normal and shear stresses due to warping in closedcross-sections (HSS) are insignificant and the total torsional moment can beassumed to be resisted by pure torsional shear stresses (Saint-Venantrsquostorsion)
3 Web stiffeners are considered for web shear stress but they are not designed
4 Modified column slenderness for double angle member is considered(Section E4 of the AISC LRFD Third Edition) Modified columnslenderness of the double angle member is computed based on the userspecified or designed number of the intermediate connectors
5 Double angles contain an adequate number of intermediate connectors (stitchplates) which make the two angles act as one Tee-like section
LRFD3 Steel Design Code and Parameters GT STRUDL
52 - 6
The sections of the AISC LRFD Third Edition specifications (96) which areconsidered by the GTSTRUDL LRFD3 code are summarized below
Section TitleChapter D Tension membersSection B7 Limiting slenderness ratiosSection D1 Design tensile strength
Chapter E Columns and other compression membersSection B7 Limiting slenderness ratiosTable B51 Limiting width to thickness ratio for unstiffened compression elementsTable B51 Limiting width to thickness ratio for stiffened compression elementsSection E2 Design compressive strength for flexural bucklingSection E3 Design compressive strength for flexural-torsional bucklingSection E4 Built-up memberSection E41 Design strength Modified column slendernessSection E42 Detailing requirements
Appendix E Columns and other compression membersAppendix E3 Design compressive strength for flexural-torsional buckling
Appendix B Design requirementsAppendix B53a Unstiffened compression elementsAppendix B53b Stiffened compression elementsAppendix B53c Design propertiesSection B53d Design strength
Chapter F Beam and other flexural membersSection F11 YieldingSection F12 Lateral-Torsional BucklingSection F12a Doubly symmetric shapes and channels with Lb Lr
Section F12b Doubly symmetric shapes and channels with Lb gt Lr
Section F12c Tees and Double angles
Appendix F Beams and other flexural membersAppendix F1 Design for flexureTable A-F11 Nominal strength parameters
Appendix F2 Design for shearAppendix F22 Design shear strengthAppendix F23 Transverse stiffeners
GT STRUDL LRFD3 Steel Design Code and Parameters
52 - 7
Section Title
Appendix G Plate GirdersAppendix G1 LimitationsAppendix G2 Design flexural strengthAppendix G3 Design shear strengthAppendix G4 Transverse stiffenersAppendix G5 Flexure-shear
Chapter H Member under combined forcesSection H1 Symmetric members subject to bending and axial forceSection H11 Doubly and singly symmetric member in flexure and tensionSection H12 Doubly and singly symmetric member in flexure and
compression
Load and Resistance Factor Design Specification for Single-Angle Members
Section Title
Section 2 TensionSection 3 ShearSection 4 CompressionSection 5 FlexureSection 51 Flexure Design StrengthSection 53 Bending About Principal AxesSection 6 Combined ForcesSection 61 Members in Flexure and Axial CompressionSection 62 Members in Flexure and Axial Tension
Load and Resistance Factor Design Specification for Steel Hollow StructuralSections
Section Title
Table 22-1 Limiting Wall Slenderness for Compression Elements
Section 3 Tension MembersSection 31 Design Tensile StrengthSection 4 Column and Other Compression Members Section 42 Design Compressive StrengthSection 5 Beams and Other Flexural MembersSection 51 Design Flexural Strength
LRFD3 Steel Design Code and Parameters GT STRUDL
52 - 8
Section Title
Section 52 Design Shear StrengthSection 6 Torsion MembersSection 61 Design Torsional StrengthSection 7 Members Under Combined ForcesSection 71 Design for Combined Flexure and Axial ForceSection 72 Design for Combined Torsion Shear Flexure andor Axial
Force
Tensile or compressive axial strengths bi-axial bending shear strengths andcombined strengths are considered for all cross-sections Parameters allowing for thechanges which occur in structural steel at high temperatures have been included and may beinvoked at the users discretion
The detailed explanation of the code parameters and cross-section properties are asfollows
1 Table LRFD31-1 Shows the parameters used by LRFD3 code TableLRFD31-1 contains the applicable parameter namestheir default values and a brief description of theparameters
2 Section LRFD32 Describes the cross-section properties used for eachshape
3 Section LRFD33 Contains detailed discussion of the parameters usedby the LRFD3 code and they are presented in thealphabetic order in this section
GT STRUDL LRFD3 Code Parameters
52 - 9
Table LRFD31-1LRFD3 Code Parameters
Parameter Default Name Value Meaning
CODE Required Identifies the code to be used for member checking ormember selection Specify LRFD3 for code name Secondorder elastic analysis using factored loads is required by theGTSTRUDL LRFD3 code Second order effect may beconsidered by using GTSTRUDL Nonlinear Analysis(Section 25 of Volume 3 of the User Reference Manual)See Sections LRFD32 and LRFD33 for a more detaileddescription of parameters and cross-section properties
TBLNAM WSHAPES9 Identifies the table of profiles to be used during selection(SELECT command) See Table LRFD31-3 for a list ofavailable table names
CODETOL 00 Percent variance from 10 for compliance with the provisionsof a code The ratio of ActualAllowable must be less thanor equal to [10 + CODETOL100]
PF 10 Area reduction factor for holesout in members subject toaxial tension
a 100000 The clear distance between transverse stiffeners This(inches) parameter is used to compute ah ratio which is used in the
computation of the limiting shear strength The default valueindicates that the shear check does not consider transversestiffeners
LRFD3 Code Parameters GT STRUDL
52 - 10
Table LRFD31-1 (continued)
LRFD3 Code Parameters
Parameter Default Name Value Meaning
SECTYPE Computed Indicates that the cross-section is rolled or welded shapeThis parameter is used to compute the value of Fr Fr is thecompressive residual stress in flange
ROLLED = rolled shape Compressive residual stress isequal to 10 ksi
WELDED = welded shape Compressive residual stressis equal to 165 ksi
Material Properties
STEELGRD A36 Identifies the grade of steel from which a member is madeSee Tables LRFD31-4 and LRFD31-5 for steel grades andtheir properties
Fy Computed Yield stress of member Computed from parameterlsquoSTEELGRDrsquo if not given
Fu Computed Minimum tensile strength of member Computed fromparameter lsquoSTEELGRDrsquo if not given
Fyf Fy Minimum yield stress of the flange If not specified it isassumed equal to the parameter lsquoFyrsquo This parameter is usedto define a hybrid cross-section See parameter lsquoFywrsquo also
Fyw Fy Minimum yield stress of the web If not specified it isassumed equal to the parameter lsquoFyrsquo This parameter is usedto define a hybrid cross-section See parameter lsquoFyfrsquo also
RedFy 10 Reduction factor for parameter lsquoFyrsquo This factor timesparameter lsquoFyrsquo gives the Fy value used by the code Used toaccount for property changes at high temperatures
GT STRUDL LRFD3 Code Parameters
52 - 11
Table LRFD31-1 (continued)
LRFD3 Code Parameters
Parameter Default Name Value Meaning
Material Properties (continued)
RedFu 10 Reduction factor for parameter lsquoFursquo Similar to parameterlsquoRedFyrsquo
REDE 10 Reduction factor for E the modulus of elasticity Similar toparameter RedFy
Slenderness Ratio
SLENCOMP 200 Maximum permissible slenderness ratio (KLr) for a membersubjected to axial compression When no value is specifiedfor this parameter the value of 200 is used for the maximumslenderness ratio
SLENTEN 300 Maximum permissible slenderness ratio (Lr) for a membersubjected to axial tension When no value is specified for thisparameter the value of 300 is used for the maximumslenderness ratio
K-Factors
COMPK NO Parameter to request the computation of the effective lengthfactors KY and KZ (Sections 22 and 23 of Volume 2A ofthe User Reference Manual)
YES = compute KY and KZ factors
KY = compute KY only
KZ = compute KZ only
NO = use default or specified values for KY andKZ
K-factor Leaning Columns Concept has not been implemented for the automatic K-factor Computation
LRFD3 Code Parameters GT STRUDL
52 - 12
Table LRFD31-1 (continued)
LRFD3 Code Parameters
Parameter Default Name Value Meaning
K-Factors (continued)
KY 10 Effective length factor for buckling about the local Y axis ofthe profile See Sections 22 and 23 of Volume 2A of theUser Reference Manual for GTSTRUDL computation ofeffective length factor KY
KZ 10 Effective length factor for buckling about the local Z axis ofthe profile See Sections 22 and 23 of Volume 2A of theUser Reference Manual for GTSTRUDL computation ofeffective length factor KZ
Print-K YES Parameter to print the computed K-factor values after thedefault code check or select command output (TRACE 4output) The default value of lsquoYESrsquo for this parameterindicates that the computed K-factor values should be printedafter the code check or select command output The columnnames attached to the start and end of the code checkedmember is also printed This printed information allows theuser to inspect the automatic detection of the columnsattached to the start and end of the designed member Avalue of lsquoNOrsquo indicates that K-factor values and the names ofthe attached columns to the start and end of the designedmember should not be printed
SDSWAYY YES Indicates the presence or absence of sidesway about the localY axis
YES = sidesway permitted
NO = sidesway prevented
K-factor Leaning Columns Concept has not been implemented for the automatic K-factor Computation
GT STRUDL LRFD3 Code Parameters
52 - 13
Table LRFD31-1 (continued)
LRFD3 Code Parameters
Parameter Default Name Value Meaning
K-Factors (continued)
SDSWAYZ YES Indicates the presence or absence of sidesway about the localZ axis
YES = sidesway permitted
NO = sidesway prevented
CantiMem NO Parameter to indicate that a member or a physical memberwhich is part of a cantilever truss should be considered as acantilever in the K-factor computation True cantilevermembers or physical members are detected automatically
NO = member or physical member is not cantilever
YES = member or physical member is cantilever
GAY Computed G-factor at the start joint of the member GAY is used in thecalculation of effective length factor KY (see parametersCOMPK KY and Sections 22 and 23 of Volume 2A of theUser Reference Manual)
GAZ ComputedG-factor at the start joint of the member GAZ is used in thecalculation of effective length factor KZ (see parametersCOMPK KZ and Sections 22 and 23 of Volume 2A of the UserReference Manual)
GBY ComputedG-factor at the end joint of the member GBY is used in thecalculation of effective length factor KY (see parametersCOMPK KY and Sections 22 and 23 of Volume 2A of the UserReference Manual)
GBZ ComputedG-factor at the end joint of the member GBZ is used in thecalculation of effective length factor KZ (see parametersCOMPK KZ and Sections 22 and 23 of Volume 2A of the UserReference Manual)
LRFD3 Code Parameters GT STRUDL
52 - 14
Table LRFD31-1 (continued)
LRFD3 Code Parameters
Parameter Default Name Value Meaning
Buckling Length
LY Computed Unbraced length for buckling about the local Y axis of theprofile The default is computed as the length of the member
LZ Computed Unbraced length for buckling about the local Z axis of theprofile The default is computed as the length of the member
FRLY 10 Fractional form of the parameter LY allows unbraced lengthto be specified as fractions of the total length Used onlywhen LY is computed
FRLZ 10 Fractional form of the parameter LZ similar to FRLY Usedonly when LZ is computed
Flexural-Torsional Buckling
KX 10 Effective length factor for torsional buckling about the localX axis of the profile This parameter is used in flexural-torsional buckling stress Fe computations
LX Computed Unbraced length for torsional buckling about the local X axisof the profile The default is computed as the length of themember This parameter is used in flexural-torsionalbuckling stress Fe computations
FRLX 10 Fractional form of the parameter LX allows unbraced lengthto be specified as fractions of the total length Used onlywhen LX is computed
GT STRUDL LRFD3 Code Parameters
52 - 15
Table LRFD31-1 (continued)
LRFD3 Code Parameters
Parameter Default Name Value Meaning
Bending Strength
CB Computed Coefficient used in computing allowable compressivebending strength (AISC LRFD Third Edition Section F12aEquation F1-3)
UNLCF Computed Unbraced length of the compression flange The default iscomputed as the length of the member In this parameter nodistinction is made between the unbraced length for the topor bottom flange See UNLCFTF or UNLCFBF
FRUNLCF 10 Fractional form of the parameter UNLCF allows unbracedlength to be specified as fractions of the total length Usedonly when UNLCF is computed
UNLCFTF Computed Unbraced length of the compression flange for the topflange When no value is specified UNLCF and FRUNLCFare used for this parameter
UNLCFBF Computed Unbraced length of the compression flange for the bottomflange When no value is specified UNLCF and FRUNLCFare used for this parameter
LRFD3 Code Parameters GT STRUDL
52 - 16
Table LRFD31-1 (continued)
LRFD3 Code Parameters
Parameter Default Name Value Meaning
Channel Parameter
Tipping YES This is the parameter indicating that the tipping effect shouldbe considered When the load is applied to the top flange ofthe channel and the flange is not braced there is a tippingeffect that reduces the critical moment A value of YES forthis parameter indicates that the flange is unbraced and theflange is loaded as such that causes tipping effect In thiscase the reduced critical moment may be conservativelyapproximated by setting the warping buckling factor X2 equalto zero A value of NO indicates that the tipping effect doesnot happen and the warping buckling factor is computedbased on the Equation F1-9 of the AISC LRFD Third Edition
Single Angle Parameter
Cby Computed Coefficient used in computing elastic lateral-torsionalbuckling moment Mob (AISC LRFD Third Edition Section53 on the page 163-6) for major axis bending (bending aboutthe principal Y axis)
Tee Parameter
SFYBend 10 Parameter to specify safety factor for the computation of thelimit state of Y axis (minor axis) bending of the tee section
Double Angle Parameters
nConnect 0 Number of connectors between individual angles The userspecified value is used during the code check When theSELECT MEMBER (design) is requested the user specifiedvalue is used unless more connectors are required If the
GT STRUDL LRFD3 Code Parameters
52 - 17
Table LRFD31-1 (continued)
LRFD3 Code Parameters
Parameter Default Name Value Meaning
Double Angle Parameters (continued)
designed number of connectors are larger than the userspecified value the computed number of connectors are usedand printed after the SELECT MEMBER result The defaultvalue of zero indicates that the angles are connected at theends only Following are additional options that you canspecify for this parameter
0 = angles are connected at the ends of the member
ndash1 = requesting the number of connectors to be computedduring code check
ndash2 = bypass modified column slenderness equationsThis will bypass the check for the Section E41 ofthe AISC LRFD Third Edition
ConnType WELDED Type of the intermediate connectors that are used for doubleangle Choices are SNUG and WELDED
SNUG = intermediate connectors that are snug-tightbolted
WELDED = intermediate connectors that are welded orfully tensioned bolted This is the default
L Computed Actual member length is used to design a number ofconnectors and to check connector spacing (Section E42 ofthe AISC LRFD) and also used in the computation of themodified column slenderness (KLr)m (Section E41 of theAISC LRFD) This parameter is used to compute the distancebetween connectors a = L(n+1) where lsquoarsquo is the distancebetween connectors lsquoLrsquo is the physical member length andlsquonrsquo is the number of connectors The default is computed asthe length of the member
LRFD3 Code Parameters GT STRUDL
52 - 18
Table LRFD31-1 (continued)
LRFD3 Code Parameters
Parameter Default Name Value Meaning
Double Angle Parameters (continued)
K 10 Effective length factor for an individual component (singleangle) This parameter is used to design a number ofconnectors and to check the connector spacing (Section E42of the AISC LRFD)
SFYBend 10 Parameter to specify safety factor for the computation of thelimit state of Y axis (minor axis) bending of the double anglesection
Round HSS (Pipes) Shear Check Parameters
avy Computed The length of essentially constant shear in the Y axisdirection of a member This parameter is used to check the Ydirection shear of a round HSS (pipe) cross-section (96)This parameter is similar to the variable lsquoarsquo in the Equation52-2 of the AISC LRFD HSS specification in the Section162 of the LRFD Third Edition The default is computed asthe length of the member
avz Computed The length of essentially constant shear in the Z axis directionof a member This parameter is used to check the Z directionshear of a round HSS (pipe) cross-section (96) Thisparameter is similar to the variable lsquoarsquo in the Equation 52-2of the AISC LRFD HSS specification in the Section 162 ofthe LRFD Third Edition The default is computed as thelength of the member
GT STRUDL LRFD3 Code Parameters
52 - 19
Table LRFD31-1 (continued)
LRFD3 Code Parameters
Parameter Default Name Value Meaning
Round HSS (Pipes) Torsion Check Parameter
LX Computed This parameter is to specify the distance between torsionalrestraints LX is used in the equation 61-2 on Page 162-8 ofAISC LRFD Third Edition (96) This parameter is similar tothe variable lsquoarsquo in the Equation 52-2 of the AISC LRFD HSSspecification in the Section 162 of the LRFD Third EditionThe default is computed as the length of the member
Rectangular Hollow Structural Section (HSS) Parameters
Cby Computed Coefficient used in computing limiting compressive bendingstrength (AISC LRFD Third Edition Section F12a EquationF1-3) for minor axis bending (bending about the Y-axis)
UNLCW Computed Unbraced length of the compression web about the local Yaxis of the profile The default is taken as length of member
FRUNLCW Computed Fractional form of the parameter UNLCW allows unbracedlength to be specified as a fraction of the total length Usedonly when UNLCW is computed
Plate Girder Parameters
Fyst Fy Minimum yield stress of the transverse stiffeners material Ifnot specified it is assumed equal to the parameter Fy
LRFD3 Code Parameters GT STRUDL
52 - 20
Table LRFD31-1 (continued)
LRFD3 Code Parameters
Parameter Default Name Value Meaning
Plate Girder Parameters (continued)
Ast 00 Parameter to specify the transverse stiffeners area Thisparameter is used to check Appendix G4 of AISC LRFD 3rd
Edition The specified transverse stiffeners area is checkedto see if it is smaller than the computed value from EquationA-G4-1 of Appendix G4 of AISC LRFD 3rd Edition Thedefault value of 00 indicates that the transverse stiffenersarea of Appendix G4 is not checked
Ist 00 Parameter to specify the transverse stiffeners moment ofinertia This parameter is used to check Appendix F23 ofAISC LRFD 3rd Edition for the required transverse stiffenersmoment of inertia The default value of 00 indicates that thetransverse stiffeners moment of inertia according to AppendixF23 is not checked
Dstiff 24 Parameter to specify the factor D that is used in the EquationA-G4-1 of Appendix G4 of AISC LRFD 3rd Edition Adefault value of 24 for single plate stiffeners is assumed Thevalue of factor D (parameter lsquoDstiffrsquo) in the Equation A-G4-1is dependent on the type of transverse stiffeners used in aplate girder Alternate values are as follows
10 = for stiffeners in pairs This is the default valuewhen the specified value for the parameterlsquoNumBarsrsquo is greater than 1
18 = for single angle stiffeners
24 = for single plate stiffeners This is the defaultvalue when the specified value for the parameterlsquoNumBarsrsquo is equal to 1
GT STRUDL LRFD3 Code Parameters
52 - 21
Table LRFD31-1 (continued)
LRFD3 Code Parameters
Parameter Default Name Value Meaning
Plate Girder Parameters (continued)
NumBars 10 Parameter to specify a number of single plate stiffeners Thedefault value for this parameter indicates 1 single platestiffener
Stiff-H 00 Parameter to specify the single plate stiffeners cross-sectionrsquosheight Parameters lsquoStiff-Hrsquo lsquoStiff-Wrsquo and lsquoNumBarsrsquo areused for the automatic computation of the parameters lsquoAstrsquoand lsquoIstrsquo The automatic computation of the parameters lsquoAstrsquoand lsquoIstrsquo is based on the rectangular bar stiffeners geometryIf transverse stiffeners are not rectangular bar parameterslsquoAstrsquo and lsquoIstrsquo should be specified
Stiff-W 00 Parameter to specify the single plate stiffeners cross-sectionrsquoswidth See parameter lsquoStiff-Hrsquo for more information
Force Limitation
FXMIN 05 (lb) Minimum axial force to be considered by the code anythingless in magnitude is taken as zero
FYMIN 05 (lb) Minimum Y-shear force to be considered by the codeanything less in magnitude is taken as zero
FZMIN 05 (lb) Minimum Z-shear force to be considered by the codeanything less in magnitude is taken as zero
LRFD3 Code Parameters GT STRUDL
52 - 22
Table LRFD31-1 (continued)
LRFD3 Code Parameters
Parameter Default Name Value Meaning
Force Limitation (continued)
MXMIN 200 (in-lb) Minimum torsional moment to be considered by the codeanything less in magnitude is taken as zero
MYMIN 200 (in-lb) Minimum Y-bending moment to be considered by the codeanything less in magnitude is taken as zero
MZMIN 200 (in-lb) Minimum Z-bending moment to be considered by the codeanything less in magnitude is taken as zero
Output Processing and System Parameters
SUMMARY NO Indicates if SUMMARY information is to be saved for themember Choices are YES or NO see Sections 29 and 72of Volume 2A of the User Reference Manual for an expla-nation
PrintLim NO Parameter to request to print the section limiting values forlimit state and load and resistance factor codes The defaultoutput from CHECK or SELECT command prints the sectionforce values A value of lsquoYESrsquo for this parameter indicatesthat the section limiting values should be printed instead ofdefault section forces
GT STRUDL LRFD3 Code Parameters
52 - 23
Table LRFD31-1 (continued)
LRFD3 Code Parameters
Parameter Default Name Value Meaning
Output Processing and System Parameters (continued)
TRACE 40 Flag indicating when checks of code provisions should beoutput during design or code checking See Section 72 ofVolume 2A of the User Reference Manual for an explanation
1 = never
2 = on failure
3 = all checks
4 = controlling ActualAllowable values and sectionforces
VALUES 10 Flag indicating if parameter or property values are to beoutput when retrieved See Section 72 of Volume 2A of theUser Reference Manual for the explanation
1 = no output
2 = output parameters
3 = output properties
4 = output parameters and properties
LRFD3 Code Parameters GT STRUDL
52 - 24
This page intentionally left blank
GT STRUDL LRFD3 Steel Design Code and Parameters
52 - 25
Table LRFD31-2
GTSTRUDL AISC Codes
Code ParameterName Table Application
LRFD3 LRFD31-1 Checks compliance of I shapes channels single angles teesVolume double angles round HSS (pipes) rectangular and square 2 - LRFD3 HSS (structural tubes) solid round square and rectangular
bars and plate girder profiles to the 1999 AISC LRFDThird Edition Specification (96)
ASD9-E ASD9-E1-1 Checks compliance of I shape profiles to the 1989 AISCVolume ASD Ninth Edition specification (72) with equations that 2 - ASD9-E have been modified to include the modulus of elasticity
(constant E) LRFD2 LRFD2 Checks compliance of I shapes pipes structural tubing plate
Volume 2A girders (subjected to bi-axial bending and axial force)single and double angles (subjected to axial forces only)shape profiles to the 1993 AISC LRFD Second EditionSpecification (81)
ASD9 ASD9 Checks compliance of I shapes single angles channels teesVolume 2A double angles solid round bars pipes solid squares and
rectangular bars and structural tubing shape profiles to the1989 AISC ASD Ninth Edition Specification (72)
78AISC 2231 Checks compliance of I shapes single angles channels teesVolume 2B solid round bars pipes solid squares and rectangular bars
and structural tubing (use code name DBLANG for doubleangle) shape profiles to the 1978 AISC Specification (33)Eighth Edition including 1980 updates
For latest (up to date) version of this table see Table 21-1a of Volume 2A
LRFD3 Steel Design Code and Parameters GT STRUDL
52 - 26
Table LRFD31-2 (continued)
GTSTRUDL AISC Codes
Code ParameterName Table Application
69AISC 2231 Checks compliance of I shapes single angles channels teesVolume 2B solid round bars pipes solid squares and rectangular bars
and structural tubing (use code name DBLANG for doubleangle) shape profiles to the 1969 AISC Specification (16)Seventh Edition including supplements 1 2 and 3
W78AISC 2231 Similar to 78AISC code except limited to checking I shapeVolume 2B profiles This code is identical to the 78AISC code which
was available in older versions of GTSTRUDL (ie versionV1M7 and older)
DBLANG 2231 Checks compliance of double angle profiles to the 1969 Volume 2B AISC Specification (16) Seventh Edition including supple-
ments 1 2 and 3
W69AISC 2231 Similar to 69AISC code except limited to checking I shapeVolume 2B profiles This code is identical to the 69AISC code which
was available in older versions of GTSTRUDL (ie versionV1M7 and older)
For latest (up to date) version of this table see Table 21-1a of Volume 2A
GT STRUDL LRFD3 Steel Design Code and Parameters
52 - 27
Table LRFD31-3
GTSTRUDL Profile Tables for theDesign based on the LRFD3 Code
Profile Shapes Reference
I shapes See Appendix C of Volume 2A for list of applicable table namesfor I shapes W S M HP shapes wide flange shapes universalbeam shapes universal column shapes etc
Channels See Appendix C of Volume 2A for a list of channel table namesapplicable to LRFD3 codes
Single Angles See Appendix C of Volume 2A for list of single angle tablenames applicable to LRFD3 code
Tees See Appendix C of Volume 2A for a list of tee table namesapplicable to LRFD3 codes
Double Angles See Appendix C of Volume 2A for list of double angle tablenames applicable to LRFD3 code
Round HSS See Appendix C of Volume 2A for list of round HSS (pipecircular hollow section) table names applicable to LRFD3 code
Rectangular HSS See Appendix C of Volume 2A for list of rectangular and squareHSS (structural tube rectangular and square hollow section) tablenames applicable to LRFD3 code
Solid Round Bars See Appendix C of Volume 2A for a list of solid round bar tablenames applicable to LRFD3 codes
Solid Square Bars See Appendix C of Volume 2A for a list of solid square bar tablenames applicable to LRFD3 codes
Solid Rectangular Bars See Appendix C of Volume 2A for a list of solid rectangular bartable names applicable to LRFD3 codes
Plate Girders See Appendix C of Volume 2A for a list of plate girder tablenames applicable to LRFD3 codes
LRFD3 Steel Design Code and Parameters GT STRUDL
52 - 28
Table LRFD31-4
ASTM Steel Grades and Associated Values of Fy and Fu Based on the1999 AISC LRFD Third Edition Specifications
Applicable Shapes W M S HP L 2L C MC WT MT and STshapes from AISC Tables
Steel GradeASTM
DesignationGroup Number Per ASTM A6
Fy Minimum Yield Stress (ksi)Fu Minimum Tensile Strength (ksi)
Group 1 Group 2 Group 3 Group 4 Group 5A36 36
583658
3658
3658
3658
A529-G50 5065
5065
NA NA NA
A529-G55 5570
5570
NA NA NA
A572-G42 4260
4260
4260
4260
4260
A572-G50 5065
5065
5065
5065
5065
A572-G55 5570
5570
5570
5570
5570
A572-G60 6075
6075
6075
NA NA
A572-G65 6580
6580
6580
NA NA
A913-G50 5060
5060
5060
5060
5060
A913-G60 6075
6075
6075
6075
6075
A913-G65 6580
6580
6580
6580
6580
A913-G70 7090
7090
7090
7090
7090
GT STRUDL LRFD3 Steel Design Code and Parameters
52 - 29
Table LRFD31-4 (continued)
ASTM Steel Grades and Associated Values of Fy and Fu Based on the1999 AISC LRFD Third Edition Specifications
Applicable Shapes W M S HP L 2L C MC WT MT and ST shapes from AISC Tables
Steel GradeASTM
DesignationGroup Number Per ASTM A6
Fy Minimum Yield Stress (ksi)Fu Minimum Tensile Strength (ksi)
Group 1 Group 2 Group 3 Group 4 Group 5A992a 50
655065
5065
5065
5065
A242 5070
5070
46b
67b42a
63a42a
63a
A588 5070
5070
5070
5070
5070
a Applicable to W shapes only
b Applicable to W and HP shapes only
NA Indicates that shapes in the corresponding group are not produced for that grade of steelGTSTRUDL assumes Fy and Fu to be zero in such cases and will not select profiles for thesecombinations of group number and steel grade Minimum yield stresses (Fy) and minimumtensile strengths (Fu) were obtained from the summary of ASTM specifications included in the1999 AISC LRFD Third Edition specification
LRFD3 Steel Design Code and Parameters GT STRUDL
52 - 30
Table LRFD31-5
ASTM Steel Grades and Associated Values of Fy and Fu Based on the1999 AISC LRFD Third Edition Specifications
Applicable Shapes Round HSS Steel Pipe and Rectangular HSS
Steel GradeASTM
DesignationApplicable Shape Series
Fy Minimum Yield Stress (ksi)Fu Minimum Tensile Strength (ksi)
Round HSS Steel Pipe Rectangular HSSA53-GB NA 35
60NA
A500-GB 4258
NA 4658
A500-GC 4662
NA 5062
A501 3658
NA 3658
A618-GIA618-GII
Thickness 34
5070 NA
5070
A618-GIA618-GII
Thickness gt 34
4667 NA
4667
A618GIII 5065
NA 5065
A242-G46 NA NA 4667
A242-G50 NA NA 5070
A588 NA NA 5070
A847 5070
NA 5070
NA Not applicable See Table LRFD31-4 for more explanation
GT STRUDL 00BS5950 Design Code and Parameters
52 - 31
522 BS5950 Design Code and Parameters
00BS5950 CodeBritish StandardBS 5950-12000
00BS595012 00BS5950 Code
The 00BS5950 code of GTSTRUDL may be used to select or check any of the followingshapes
I shapes Subjected to bending and axial forceSingle Angles Subjected to axial force onlyCircular Hollow Sections (Pipes) Subjected to bending and axial force
The term I shapes is used to mean rolled or welded I and H beams and columns universalbeams and columns joists universal bearing piles W S M and HP profiles with doublysymmetric cross-sections
The code is based on the BS 5950-12000 British Standard Structural use of steelwork inbuilding Part 1 Code of practice for design rolled and welded sections amendment number13199 issued May 2001 The 00BS5950 code utilizes the limit state design techniques of theBSI (British Standard Institution) specification
The following assumptions are made throughout the 00BS5950 code
1 Torsional stresses are usually small when compared to axial and bending stressesand may be neglected No checks are made for torsion The designer is remindedto check the torsional stresses whenever they become significant
2 Web stiffeners are considered for web shear stress but they are not designed
GT STRUDLreg
S t e e l D e s i g n C o d e U s e r M a n u a l
Volume 2 - 00BS5950
Computer Aided Structural Engineering CenterSchool of Civil and Environmental Engineering
Georgia Institute of TechnologyAtlanta Georgia 30332-0355
Rev T ii V2
This page intentionally left blank
V2 iii Rev T
GTSTRUDL Users Manual Revision History
Revision No
DateReleased Description
T 2006
V2 iv Rev T
This page intentionally left blank
V2 v Rev T
NOTICES
GTSTRUDLreg User Manual Volume 2 - 00BS5950 Steel Design Codes Revision T isapplicable to Version 29 of GTSTRUDL released 2006 and subsequent versions
GTSTRUDLreg computer program is proprietary to and a trade secret of the Georgia TechResearch Corporation Atlanta Georgia 30332
GTSTRUDLreg is a registered service mark of the Georgia Tech Research CorporationAtlanta Georgia USA
DISCLAIMER
NEITHER GEORGIA TECH RESEARCH CORPORATION NOR GEORGIA INSTITUTEOF TECHNOLOGY MAKE ANY WARRANTY EXPRESSED OR IMPLIED AS TO THEDOCUMENTATION FUNCTION OR PERFORMANCE OF THE PROGRAMDESCRIBED HEREIN AND THE USERS OF THE PROGRAM ARE EXPECTED TOMAKE THE FINAL EVALUATION AS TO THE USEFULNESS OF THE PROGRAM INTHEIR OWN ENVIRONMENT
Commercial Software Rights Legend
Any use duplication or disclosure of this software by or for the US Government shall berestricted to the terms of a license agreement in accordance with the clause at DFARS2277202-3 (June 2005)
This material may be reproduced by or for the US Government pursuant to the copyrightlicense under the clause at DFARS 252227-7013 September 1989
Georgia Tech Research CorporationGeorgia Institute of Technology
Atlanta Georgia 30332-0355
Copyright copy 2006
Georgia Tech Research CorporationAtlanta Georgia 30332
ALL RIGHTS RESERVED
Printed in United States of America
V2 vi Rev T
This page intentionally left blank
V2 vii Rev T
Table of Contents
Chapter Page
NOTICES v
DISCLAIMER v
Commercial Software Rights Legend v
Table of Contents vii
00BS59501 GTSTRUDL Steel Design 00BS5950 Code 1 - 100BS595011 Introduction 11 - 100BS595012 00BS5950 Code 12 - 1
00BS59502 Properties used by 00BS5950 2 - 100BS59503 Parameters Used by 00BS5950 3 -1
00BS59504 Provisions of 00BS5950 4 - 100BS595041 General Nomenclature for 00BS5950 41 - 100BS595042 00BS5950 Provisions for I shapes 42 - 100BS595043 00BS5950 Provisions for Single Angle 43 - 100BS595044 00BS5950 Provisions for Circular Hollow Section
(CHS Pipe) 44 - 1
Appendix A References A - 1Appendix B Use of GTTABLE B - 1Appendix C GTSTRUDL Tables of Steel Profiles C - 1
List of Figures
Figure 00BS59501-1 Local Axes for Design with 00BS5950 12 - 2Figure 00BS59502-1 Local Axes for Design with 00BS5950 2 - 2Figure 00BS59503-1 Local Axis Buckling 3 - 14Figure 00BS59503-2 SIDESWAY Conditions 3 - 21Figure 00BS595042-1 Effective cross-section for determining Aeff 42 - 6Figure 00BS595042-2 Effective cross-section web fully effective for determining
Zyeff and Zzeff 42 - 10Figure 00BS595042-3 Bending Stresses for I Shapes 42 - 32Figure 00BS595044-1 Bending Stresses for Circular Hollow Section
(CHS Pipe) 44 - 17
V2 viii Rev T
List of Tables
Table 00BS59501-1 00BS5950 Code Parameters 12 - 7Table 00BS59501-2 GTSTRUDL Profile Tables for the Design based
on the 00BS5950 Code 12 - 17Table 00BS59501-3 Steel Grades Based on the BS 5950-12000 (00BS5950)
and 1993 Eurocode (EC3) Specification 12 - 18Table 00BS59501-4 Effective Factor Values EFLEY and EFLEZ for
Nominal Effective Length LEy and LEz computationBritish Standard BS 5950-12000 Specification 12 - 20
Table 00BS59501-5 Effective Length LE British Standard BS 5950-12000 Specification 12 - 21
Table 00BS59503-1 Parameters in 00BS5950 3 - 2Table 00BS59503-2 Effective Length LE British Standard BS 5950-1
2000 Specification 3 - 10Table 00BS59503-3 Effective Factor Values EFLEY and EFLEZ for
Nominal Effective Length LEy and LEz computationBritish Standard BS 5950-12000 Specification 3 - 11
Table 00BS59503-4 Steel Grades Based on the BS 5950-12000 (00BS5950) and 1993 Eurocode (EC3) Specification 3 - 24
Table 00BS595042-1 Flange Classification Provision lsquoClass-Frsquo for 00BS5950 Code 42 - 15
Table 00BS595042-2 Web Classification Provision lsquoClass-Wrsquo for 00BS5950 Code 42 - 16
Table 00BS595043-1 Single Angle Classification Provision lsquoClassrsquo for 00BS5950 Code 43 - 6
Table 00BS595044-1 Classification Provision lsquoClass-Axrsquo for 00BS5950 Code 44 - 6
Table 00BS595044-2 Classification Provision lsquoClass-Bersquo for 00BS5950 Code 44 - 7
GT STRUDL GTSTRUDL Steel Design Codes
V2 00BS595011 - 1 Rev T
00BS59501 GTSTRUDL Steel Design 00BS5950 Code
00BS595011 Introduction
The purpose of this volume is to discuss in detail the parameters properties and thecode provisions for the GTSTRUDL steel design 00BS5950 code This volume is onlyapplicable to steel design 00BS5950 code
GTSTRUDL Steel Design Codes GT STRUDL
Rev T 00BS595011 - 2 V2
This page intentionally left blank
GT STRUDL 00BS5950 Code
V2 00BS595012 - 1 Rev T
00BS5950 CodeBritish StandardBS 5950-12000
00BS595012 00BS5950 Code
The 00BS5950 code of GTSTRUDL may be used to select or check any of thefollowing shapes
I shapes Subjected to bending and axial forceSingle Angles Subjected to axial force onlyCircular Hollow Sections (Pipes) Subjected to bending and axial force
The term I shapes is used to mean rolled or welded I and H beams and columnsuniversal beams and columns joists universal bearing piles W S M and HP profiles withdoubly symmetric cross-sections
The code is based on the BS 5950-12000 British Standard Structural use ofsteelwork in building Part 1 Code of practice for design rolled and welded sectionsamendment number 13199 issued May 2001 The 00BS5950 code utilizes the limit statedesign techniques of the BSI (British Standard Institution) specification
The following assumptions are made throughout the 00BS5950 code
1 Torsional stresses are usually small when compared to axial and bendingstresses and may be neglected No checks are made for torsion Thedesigner is reminded to check the torsional stresses whenever they becomesignificant
2 Web stiffeners are considered for web shear stress but they are not designed
00BS5950 Code GT STRUDL
Rev T 00BS595012 - 2 V2
Figure 00BS59501-1 Local Axes for Design with 00BS5950
GT STRUDL 00BS5950 Code
V2 00BS595012 - 3 Rev T
The sections of the BS 5950-12000 specifications (95) that are considered by theGTSTRUDL 00BS5950 code are summarized below
Section Title
3 Properties of materials and section properties35 Classification of cross-sections351 General352 Classification353 Flanges of compound I- or H-sections
Table 11 Limiting width-to-thickness ratios for sectionsother than CHS and RHS
355 Stress ratios for classification3562 I- or H-sections with equal flanges3564 Circular hollow sections3622 Effective area3623 Effective modulus when web is fully effective364 Equal-leg angle sections365 Alternative method366 Circular hollow sections
4 Design of structural members423 Shear capacity
425 Moment capacity4252 Low shear4253 High shear
43 Lateral-torsional buckling434 Destabilizing load435 Effective length for lateral-torsional buckling
Table 13 Effective length LE for beams withoutintermediate restraint
4362 I- H- channel and box sections with equal flanges4364 Buckling resistance moment4365 Bending strength pb
4366 Equivalent uniform moment factor mLT
Table 18 Equivalent uniform moment factor mLT forlateral-torsional buckling
00BS5950 Code GT STRUDL
Rev T 00BS595012 - 4 V2
Section Title
4369 Ratio $W
445 Shear buckling resistance4452 Simplified method4453 More exact method
46 Tension members461 Tension capacity472 Slenderness
47 Compression members472 Slenderness474 Compression resistance475 Compressive strength
Table 23 Allocation of strut curve
48 Members with combined moment and axial force482 Tension members with moments4822 Simplified method4823 More exact method
483 Compression members with moments4832 Cross-section capacity
4833 Member buckling resistance48331 Simplified method
Table 26 Equivalent uniform moment factor m for flexuralbuckling
48332 More exact method for I- or H-sections with equal flangesTable 26 Equivalent uniform moment factor m for flexural
buckling48333 More exact method for CHS RHS or box sections with equal flanges
Table 26 Equivalent uniform moment factor m forflexural buckling
49 Members with biaxial moments
GT STRUDL 00BS5950 Code
V2 00BS595012 - 5 Rev T
Section Title
Annex B (normative)Lateral-torsional buckling of members subject to bending
B2 Buckling resistanceB21 Bending strengthB22 Perry factor and Robertson constantB23 Uniform I H and channel sections with equal flanges
Annex C (normative)Compressive strength
C1 Strut formulaC2 Perry factor and Robertson constant
Annex H (normative)Web buckling resistance
H1 Shear buckling strength
Annex I (normative)Combined axial compression and bending
I2 Reduced plastic moment capacityI21 I- or H-section with equal flanges
Tensile or compressive axial stresses bi-axial bending shear stresses and combinedstresses are considered for all cross-sections except single angles (tension or compressionaxial stresses only) Provisions for columns in simple construction are included Parametersallowing for the changes which occur in structural steel at high temperatures have beenincluded and may be invoked at the users discretion
The detailed explanation of the code parameters cross-section properties generalnomenclature and code equations are as follows
1 Table 00BS59501-1 Shows the parameters used by 00BS5950 codeTable 00BS59501-1 contains the applicable
parameter names their default values and a briefdescription of the parameters
2 Section 00BS59502 Describes the cross-section properties used foreach shape
00BS5950 Code GT STRUDL
Rev T 00BS595012 - 6 V2
3 Section 00BS59503 Contains detail discussion of the parameters usedby the 00BS5950 code and they are presented inthe alphabetic order in this section
4 Sections 00BS59504 Describes the subsections in the Section00BS59504
5 Section 00BS595041 Defines the symbols used in the 00BS5950 codeprovisions
6 Section 00BS595042 Contains detailed discussion of the codeprovisions and the equations applicable to the Ishape cross-sections subjected to bending andaxial forces
7 Section 00BS595043 Contains detailed discussion of the codeprovisions and the equations applicable to thesingle angle cross-sections subjected to axial forceonly
8 Section 00BS595044 Contains detailed discussion of the codeprovisions and the equations applicable to thecircular hollow sections (CHS pipes) subjected tobending and axial forces
GT STRUDL 00BS5950 Code Parameters
V2 00BS595012 - 7 Rev T
Table 00BS59501-1
00BS5950 Code Parameters
Parameter Default Name Value Meaning
CODE Required Identifies the code to be used for member checking ormember selection Specify 00BS5950 for code nameSee Sections 00BS59502 00BS59503 and 00BS59504for a more detailed description
TBLNAM UNIBEAMS Identifies the table of profiles to be used during selection(SELECT command) See Table 00BS59501-2 forchoices
METHOD EXACT Identifies the design method This parameter indicates thetype of method that should be used for the shear orcombined capacity checks BOTH = Use simplified and the more exact
methods See Sections 445 482 and483 of BS 5950-12000 (95)
EXACT = Use the more exact method SeeSections 4453 4823 48332 and48333 of BS 5950-12000 (95)
SIMPLIFY = Use simplified method See Sections4452 4822 and 4832 of BS 5950-12000 (95)
SECTYPE ROLLED Indicates that the cross-section is rolled or welded shapeThis parameter is used to determine the equations that areapplicable to the rolled or welded shapeROLLED = Member is hot rolledWELDED = Member is weldedcoldformed
00BS5950 Code Parameters GT STRUDL
Rev T 00BS595012 - 8 V2
Table 00BS59501-1 (continued)
00BS5950 Code Parameters
Parameter Default Name Value Meaning
SHRAREAF Computed SHeaR AREA Factor is used for the computation of theshear area When an alternate value other than COM-PUTE or TABLE is specified shear area is computed asthe SHRAREAF times the cross sectional area (AV = AY= SHRAREAF times AX)COMPUTE = Compute the shear area based on the
Section 423 of BS 5950-12000 (95)except for single and double anglesShear area for single and double anglesare extracted from GTSTRUDL or US-ER table
TABLE = Shear area from GTSTRUDL or USERtable is used
a 2540000(mm) Distance between web stiffeners This parameter is usedto compute ad ratio ad is the ratio of the distancebetween stiffeners to web depth An arbitrary high valueof 2540000 (mm) has been assumed as a default toindicate that the web stiffeners are absent A value isnecessary to account for web stiffeners in the shearcapacity calculation (Provisions 4452 and 4453)
SimpSupp NO Indicates that if a member is simply supported or notThis parameter is used to determine the equations that areapplicable to the simply supported members (Provisionslsquo4252Zrsquo lsquo4253Zrsquo lsquo4252Yrsquo and lsquo4253YrsquoNO = Member is not simply supportedYES = Member is simply supported
CODETOL 00 Percent variance from 10 for compliance with the provi-sions of a code The ratio of actuallimiting must be lessthan or equal to [10 + CODETOL100]
GT STRUDL 00BS5950 Code Parameters
V2 00BS595012 - 9 Rev T
Table 00BS59501-1 (continued)
00BS5950 Code Parameters
Parameter Default Name Value Meaning
PF 10 Area reduction factor for holesout in members subject toaxial tension
Material Properties
STEELGRD S235JRG2 Identifies the grade of steel from which a member ismade See Table 00BS59501-3 for STEEL GRaDes andtheir properties
Py Computed Design strength py (yield stress) of member Computedfrom parameter STEELGRD if not given
REDPy 10 Reduction factor for parameter Py This factor timesparameter Py gives the design strength (py) value used bythe code Used to account for property changes at hightemperatures
Pyf Py Design strength of the flange If not specified it isassumed equal to the parameter Py This parameter isused to define a hybrid cross-section see parameter Pywalso
Pyw Py Design strength of the web If not specified it is assumedequal to the parameter Py This parameter is used todefine a hybrid cross-section see parameter Pyf also
REDE 10 Reduction factor for E the modulus of elasticity Similarto REDPy
00BS5950 Code Parameters GT STRUDL
Rev T 00BS595012 - 10 V2
Table 00BS59501-1 (continued)
00BS5950 Code Parameters
Parameter Default Name Value Meaning
Slenderness Ratio
SLENCOMP Computed Maximum permissible slenderness ratio (LEr KLr) fora member subjected to axial compression The defaultvalue for maximum compression slenderness ratio isequal to 180
SLENTEN Computed Maximum permissible slenderness ratio (Lr) for amember subjected to axial tension Only a user-specifiedvalue will initiate the slenderness ratio check for a tensionmember
Effective Length for a Compression Member
EFLEY 10 Effective factor value used for the computation ofnominal effective length LEy = EFLEY times LY for acompression member Nominal effective length LEY isused in the computation of maximum slenderness ratioabout the local Y axis of the profile See Table00BS59501-4 or Sections 472 473 and Table 22 ofBS 5950-12000 (95) for the EFLEY values
LY Computed Unbraced length for buckling about the local Y axis of thecross-section This parameter is used to compute nominaleffective length LEy for a compression member (LEy =EFLEY times LY) The default value is computed as a lengthof the member
FRLY 10 Fractional form of the parameter LY allows unbracedlength to be specified as fractions of the total length Usedonly when default value of lsquoComputedrsquo is used forparameter LY (LY = FRLY times Member Length)
GT STRUDL 00BS5950 Code Parameters
V2 00BS595012 - 11 Rev T
Table 00BS59501-1 (continued)
00BS5950 Code Parameters
Parameter Default Name Value Meaning
Effective Length for a Compression Member (continued)
EFLEZ 10 Effective factor value used for the computation of nominaleffective length LEz = EFLEZ times LZ for a compressionmember Nominal effective length LEZ is used in the com-putation of maximum slenderness ratio about the local Z axisof the profile See Table 00BS59501-4 or Sections 472473 and Table 22 of BS 5950-12000 (95) for the EFLEZvalues
LZ Computed Unbraced length for buckling about the local Z axis of thecross-section This parameter is used to compute nominaleffective length LEz for a compression member (LEz = EFLEZtimes LZ) The default value is computed as a length of themember
FRLZ 10 Fractional form of the parameter LZ allows unbraced lengthto be specified as fractions of the total length Used onlywhen default value of lsquoComputedrsquo is used for parameter LZ(LZ = FRLZ times Member Length)
Effective Length for Lateral-Torsional Buckling
LE LLT Effective length of a member for lateral torsional bucklingof a beam with restraints at the ends Default value is theeffective length between restraints against lateral-torsionalbuckling of a member under bending see parameter LLT(LE = EFLE times LLT) See Table 00BS59501-5 foralternative values and also see Table 13 and 14 of theBS5950-12000 (95)
00BS5950 Code Parameters GT STRUDL
Rev T 00BS595012 - 12 V2
Table 00BS59501-1 (continued)
00BS5950 Code Parameters
Parameter Default Name Value Meaning
Effective Length for Lateral-Torsional Buckling (continued)
EFLE 10 Effective factor value used for the computation of theeffective length LE of a member under bending Used onlywhen default value of LLT is used for parameter LE (LE =EFLE times LLT see Table 00BS59501-5 and parameter LE)
LLT Computed Segment length between restraints against lateral-torsionalbuckling (unbraced length) This parameter generally usedto specify the segment length of the compression flangerestraint against lateral-torsional buckling (unbraced lengthof the compression flange) Computed as length of member
FRLLT 10 Fractional value used for the computation of the unbracedlateral-torsional buckling length of a member LLT Usedonly when default value of lsquoComputedrsquo is used for parameterLLT (LLT = FRLLT times Member Length)
Equivalent Uniform Moment Factors
mLT Computed Equivalent uniform moment factor for lateral-torsionalbuckling (mLT) which is used in the member bucklingresistance equations This parameter modifies Z axisbending buckling capacity in combined axial and bendingcapacity equations See Section 00BS59503 for moreexplanation
my Computed Equivalent uniform moment factor for flexural buckling(my) which is used in the member buckling resistanceequations This parameter modifies Y axis bending capacityin combined axial and bending capacity equations SeeSection 00BS59503 for more explanation
GT STRUDL 00BS5950 Code Parameters
V2 00BS595012 - 13 Rev T
Table 00BS59501-1 (continued)
00BS5950 Code Parameters
Parameter Default Name Value Meaning
Equivalent Uniform Moment Factors (continued)
mz Computed Equivalent uniform moment factor for flexural buckling(mz) which is used in the member buckling resistanceequations This parameter modifies Z axis bending capacityin combined axial and bending capacity equations SeeSection 00BS59503 for more explanation
myz Computed Equivalent uniform moment factor for lateral flexuralbuckling (myz) which is used in the member out-of-planebuckling resistance equations This parameter modifies Yaxis bending capacity in combined axial and bendingcapacity equations See Section 00BS59503 for moreexplanation
SDSWAYY YES Indicates the presence or absence of SiDeSWAY about thelocal Y axisYES = Sidesway permittedNO = Sidesway prevented
SDSWAYZ YES Indicates the presence or absence of SiDeSWAY about thelocal Z axisYES = Sidesway permittedNO = Sidesway prevented
00BS5950 Code Parameters GT STRUDL
Rev T 00BS595012 - 14 V2
Table 00BS59501-1 (continued)
00BS5950 Code Parameters
Parameter Default Name Value Meaning
Equivalent Uniform Moment Factors (continued)
DESTLDY YES Indicates the presence or absence of a DESTabilizing LoaDwhich causes movement in the member local Y axisdirection (and possibly rotation about the member local Yaxis) Destabilizing load conditions exist when a load isapplied in the local Z axis direction of a member and boththe load and the member are free to deflect laterally (andpossibly rotationally also) relative to the centroid of themember This parameter is only applicable to LOADS listor ALL LOADS of the PARAMETERS commandYES = Destabilizing loadNO = Normal load
DESTLDZ YES Indicates the presence or absence of a DESTabilizing LoaDwhich causes movement in the member local Z axisdirection (and possibly rotation about the member local Zaxis) Destabilizing load conditions exist when a load isapplied to the top flange (local Y axis load) of a member andboth the load and the flange are free to deflect laterally (andpossibly rotationally also) relative to the centroid of themember This parameter is only applicable to LOADS listor ALL LOADS of the PARAMETERS commandYES = Destabilizing loadNO = Normal load
Force Limitation
FXMIN 2224 (N) Minimum axial force to be considered by the code anythingless in magnitude is taken as zero Units are in newtons (N)
FYMIN 2224 (N) Minimum Y-shear force to be considered by the codeanything less in magnitude is taken as zero
GT STRUDL 00BS5950 Code Parameters
V2 00BS595012 - 15 Rev T
Table 00BS59501-1 (continued)
00BS5950 Code Parameters
Parameter Default Name Value Meaning
Force Limitation (continued)
FZMIN 2224 (N) Minimum Z-shear force to be considered by the codeanything less in magnitude is taken as zero
MYMIN 22600 Minimum Y-bending moment to be considered by the(mm-N) code anything less in magnitude is taken as zero
MZMIN 22600 Minimum Z-bending moment to be considered by the(mm-N) code anything less in magnitude is taken as zero
Output Processing
MXTRIALS 5000 Maximum number of profiles to be tried when designing amember Default is larger than the number of profiles inmost tables
SUMMARY NO Indicates if SUMMARY information is to be saved for themember Choices are YES or NO see Sections 29 and 72of Volume 2A of the User Reference Manual for an expla-nation
PrintLim NO Parameter to request to print the section limiting values forlimit state and load and resistance factor codes Thisparameter is applicable to the steel design CHECK andSELECT commands The default output from CHECK orSELECT command prints the section force values A valueof lsquoYESrsquo for this parameter indicates that the section limitingvalues should be printed instead of default section forces
00BS5950 Code Parameters GT STRUDL
Rev T 00BS595012 - 16 V2
Table 00BS59501-1 (continued)
00BS5950 Code Parameters
Parameter Default Name Value Meaning
Output Processing (continued)
TRACE 40 Flag indication when checks of code provisions should beoutput during design or code checking See Section 72 ofVolume 2A of the User Reference Manual for theexplanation1 = never2 = on failure3 = all checks4 = controlling ActualAllowable values and section
forces
VALUES 10 Flag indication if parameter or property values are to beoutput when retrieved See Section 72 of Volume 2A of theUser Reference Manual for the explanation1 = no output2 = output parameters3 = output properties4 = output parameters and properties
GT STRUDL 00BS5950 Code Parameters
V2 00BS595012 - 17 Rev T
Table 00BS59501-2
GTSTRUDL Profile Tables for theDesign based on the 00BS5950 Code
Profile Shapes Reference
I shapes See Appendix C of Volume 2A for list of ApplicableTable names for universal beams universal columnsjoists universal bearing piles I shapes W S M HPshapes wide flange shapes etc
Single Angles See Appendix C of Volume 2A for list of single angletable names applicable to 00BS5950 code
Circular Hollow Sections See Appendix C of Volume 2A for list of circular hollowsection (pipe round HSS) table names applicable to00BS5950 code
00BS5950 Code Parameters GT STRUDL
Rev T 00BS595012 - 18 V2
Table 00BS59501-3
Steel Grades Based on the BS 5950-12000 (00BS5950) and 1993 Eurocode (EC3) Specification
Steel GradeNominal Yield Strength fy (Nmm2) Ultimate Tensile Strength fu
t 16 16lt t 40 40lt t 63 63lt t 80 80lt t 100 100lt t 150 150lt t 200 200lt t 250 t 100 100lt t 150 150lt t 250
S185 185 175 290
S235JR 235 225 340
S235JRG1 235 225 340
S235JRG2 235 225 215 215 215 195 185 175 340 340 320
S235J0 235 225 215 215 215 195 185 175 340 340 320
S235J2G3 235 225 215 215 215 195 185 175 340 340 320
S235J2G4 235 225 215 215 215 195 185 175 340 340 320
S275JR 275 265 255 245 235 225 215 205 410 400 380
S275J0 275 265 255 245 235 225 215 205 410 400 380
S275J2G3 275 265 255 245 235 225 215 205 410 400 380
S275J2G4 275 265 255 245 235 225 215 205 410 400 380
S275N 275 265 255 245 235 225 370 350
S275NL 275 265 255 245 235 225 370 350
GT STRUDL 00BS5950 Code Parameters
V2 00BS595012 - 19 Rev T
Table 00BS59501-3 (continued)
Steel Grades Based on the BS 5950-12000 (00BS5950) and 1993 Eurocode (EC3) Specification
Steel GradeNominal Yield Strength fy (Nmm2) Ultimate Tensile Strength fu
t 16 16lt t 40 40lt t 63 63lt t 80 80lt t 100 100lt t 150 150lt t 200 200lt t 250 t 100 100lt t 150 150lt t 250
S355JR 355 345 335 325 315 295 285 275 490 470 450
S355J0 355 345 335 325 315 295 285 275 490 470 450
S355J2G3 355 345 335 325 315 295 285 275 490 470 450
S355J2G4 355 345 335 325 315 295 285 275 490 470 450
S355K2G3 355 345 335 325 315 295 285 275 490 470 450
S355K2G4 355 345 335 325 315 295 285 275 490 470 450
S355N 355 345 335 325 315 295 470 450
S355NL 355 345 335 325 315 295 470 450
S420N 420 400 390 370 360 340 520 500
S420NL 420 400 390 370 360 340 520 500
S460N 460 440 430 410 400 550
S460NL 460 440 430 410 400 550
00BS5950 Code Parameters GT STRUDL
Rev T 00BS595012 - 20 V2
Table 00BS59501-4
Effective Factor Values EFLEY and EFLEZ forNominal Effective Length LEy and LEz computation
British Standard BS 5950-12000 Specification
a) non-sway mode
Restraint (in the plane under consideration) by other parts of structure EFLEYand
EFLEZEffectively held inposition at both ends
Effectively restrained in direction at both ends 07Partially restrained in direction at both ends 085Restrained in direction at one end 085Not restrained in direction at either end 10
b) sway mode
One end Other end EFLEYand
EFLEZEffectively held inposition and restrainedin direction
Not held inposition
Effectively restrained in direction 12Partially restrained in direction 15Not restrained in direction 20
Excluding angle channel or T-section struts designed in accordance with Section4710 of the BS 5950-12000 (95)
ExamplePARAMETERS
EFLEY 15 MEMBER 1 $ LEy = 15LY for member 1EFLEZ 12 MEMBER 25 $ LEz = 12LZ for member 25
LY and LZ are the unbraced length for buckling about the local Y and Z axis of the cross-section (see parameter LY and LZ)
GT STRUDL 00BS5950 Code Parameters
V2 00BS595012 - 21 Rev T
Table 00BS59501-5
Effective Length LE
British Standard BS 5950-12000 Specification
Conditions of restraint at supports Alternate values forParameter LE
Loading conditions
Normal
DESTLDZ = NO
Destabilizing
DESTLDZ = YES
Default value for parameter LE LLT EFLLTtimesLLT EFLLTtimesLLT
Compression flange laterally restrained Nominal torsional restraint against rotation about longitudinal axis
Both flanges fully restrained againstrotation on plan
A1 07LLT 085LLT
Compression flange fully restrainedagainst rotation on plan
A2 075LLT 09LLT
Both flanges partially restrained againstrotation on plan
A3 08LLT 095LLT
Compression flange partially restrainedagainst rotation on plan
A4 085LLT 10LLT
Both flanges free to rotate on plan A5 10LLT 12LLT
Compression flange laterally unrestrained Both flanges free to rotate on plan
Partial torsional restraint against rotationabout longitudinal axis provided byconnection of bottom flange to supports
A6 10LLT + 2D 12LLT + 2D
Partial torsional restraint against rotationabout longitudinal axis provided only bypressure of bottom flange onto supports
A7 12LLT + 2D 14LLT + 2D
ExamplePARAMETERS
DESTLDZ NO LOAD 2DESTLDZ YES LOAD 5LE A3 MEMBER 1 $ LE = 08LLT for load 2 and
$ LE = 095LLT for load 5LE A7 MEMBER 8 $ LE = 12LLT+2D for load 2 and
$ LE = 14LLT+2D for load 5
1 D is the depth of cross-section (table property YD)2 Default value for parameter EFLLT is equal to 103 For cantilevers and other types of beams not in Table 00BS59501-6 use parameter EFLLT to specify the effective length
factor (LE = EFLLTtimesLLT)
00BS5950 Code Parameters GT STRUDL
Rev T 00BS595012 - 22 V2
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GT STRUDL Properties used by 00BS5950
V2 00BS59502 - 1 Rev T
00BS59502 Properties used by 00BS5950
This section describes the profile properties used by the 00BS5950 code Since eachshape has different properties that are required by the design code the properties of eachshape are listed separately The tables supplied with GTSTRUDL contain these propertiesrequired for design in addition to the properties required for analysis New tables created bythe user should include the same properties if the 00BS5950 code is to be used Theorientation of the principle axes (Z and Y) for each shape is shown in Figure 00BS59502-1
Properties Used by 00BS5950 GT STRUDL
Rev T 00BS59502 - 2 V2
Figure 00BS59502-1 Local Axes for Design with 00BS5950
GT STRUDL Properties used by 00BS5950
V2 00BS59502 - 3 Rev T
I Shapes
For universal shapes W shapes and other doubly symmetric I beams thefollowing properties are required
AX = cross-sectional areaAY = Y axis shear area computed as the total profile depth (YD)
times the web thickness (WBTK)AZ = Z axis shear area computed as 23 of the total flange areaIX = torsional moment of inertiaIY = moment of inertia about the Y axisIZ = moment of inertia about the Z axisRY = radius of gyration about the Y axisRZ = radius of gyration about the Z axisSY = section modulus about the Y axisSZ = section modulus about the Z axisZY = plastic modulus about the Y axisZZ = plastic modulus about the Z axisFLTK = flange thicknessWBTK = web thicknessYD = total profile depthYC = positive Y direction distance from the Z axis to the extreme
fiber along the Y axis (half of the total profile depth)ZD = flange widthZC = positive Z direction distance from the Y axis to the extreme
fiber along the Z axis (half of the flange width)INTYD = web depth (clear depth of the web) This is the property d in
the BS 5950-12000 Specification (95) and GTSTRUDL Britishtables contain this value in the database Web depth (cleardepth of the web) is computed as cross-section depth minustwice the flange thickness and minus twice the connectioncurve radius between the web and the flange This property inother tables like AISC tables have slightly different definitionFor example INTYD in the AISC tables are defined as the totalprofile depth (YD) minus twice the flange thickness (FLTK)This property for welded section is defined as the total profiledepth (YD) minus twice the flange thickness (FLTK)
Properties Used by 00BS5950 GT STRUDL
Rev T 00BS59502 - 4 V2
BF2TF = this is the property taken from the table database The bT ratioof the flange computed as frac12 the flange width (property lsquoZDrsquo)divided by the flange thickness (property lsquoFLTKrsquo) If thisproperty is not available frac12 the flange width (property lsquoZDrsquo)divided by the flange thickness (property lsquoFLTKrsquo) is used
EY = distance from the centroid to the shear center parallel to the Yaxis
EZ = distance from the centroid to the shear center parallel to the Zaxis
H or CW = warping constantND = nominal depthX = torsional index (corresponds to x in BS 5950-12000) If not
specified the torsional index is computed based on the equationgiven in the Annex B23 of BS 5950-12000 (95)
U = buckling parameter (corresponds to u in BS 5950-12000) Ifnot specified the buckling parameter is computed based on theequation given in the Annex B23 of BS 5950-12000 (95)
WEIGHT = weight per unit lengthGRPNUM = 10SHAPE = a number that indicates the profile shape
= 10 I shapes= 12 H shapes
GT STRUDL Properties used by 00BS5950
V2 00BS59502 - 5 Rev T
Single Angles
For single angles the properties are defined with respect to the principleaxes the following properties are required
AX = cross-sectional areaAY = Y-shear area along the Y-principle axis AY is taken as a value
that will produce the maximum transverse shear from theequation FYAY where FY is the Y-shear force in the Y-principle axis direction In this case AY is taken as the term(IZtimesTHICKQZ) where QZ is the first moment of the areaabove the Z-principle axis about the Z-principle axis See SPTimoshenko and JM Gere Mechanics of Materials D VonNostrand New York 1972
AZ = Z-shear area along the Z-principle axis AZ is taken as a valuethat will produce the maximum transverse shear from theequation FZAZ where FZ is the Z-shear force in the Z-principle axis direction In this case AZ is taken as the term(IYtimesTHICKQY) where QY is the first moment of the areaabove the Y-principle axis about the Y-principle axis See SPTimoshenko and JM Gere Mechanics of Materials D VonNostrand New York 1972
IX = torsional moment of inertiaIY = moment of inertia about the Y axisIZ = moment of inertia about the Z axisRY = radius of gyration about the Y axisRZ = radius of gyration about the Z axisSY = positive direction section modulus about the Y axis (IYZC)SYS = negative direction section modulus about the Y axis (IY(ZD-
ZC)) (note if both legs are equal LEG1 = LEG2 then SY =SYS)
SZ = positive direction section modulus about the Z axis (IZYC)SZS = negative direction section modulus about the Z axis (IZ(YD-
YC))THICK = thickness of the single angleLEG1 = length of the longer leg
Properties Used by 00BS5950 GT STRUDL
Rev T 00BS59502 - 6 V2
LEG2 = length of the shorter legYD = depth parallel to the Y axis
= LEG2timescos (ALPHA)+THICKtimessin (ALPHA)YC = positive Y direction distance from the Z axis to the extreme
fiber along the Y axisZD = depth parallel to the principle Z axis
= LEG1timescos (ALPHA) + LEG2timessin (ALPHA)ZC = positive Z direction distance from the Y axis to the extreme
fiber along the Z axisALPHA = angle between the longer leg of the angle and the principle Z
axisEY = distance from the centroid to the shear center parallel to the
principle Y axisEZ = distance from the centroid to the shear center parallel to the
principle Z axisWEIGHT = weight per unit lengthGRPNUM = 10SHAPE = a number that indicates the profile shape
= 30 single angles
GT STRUDL Properties used by 00BS5950
V2 00BS59502 - 7 Rev T
Circular Hollow Sections (Pipes)
For circular hollow sections (pipes) the following properties are required
AX = cross-sectional areaAY = Y axis shear area computed as frac12 of AXAZ = Z axis shear area computed as frac12 of AXIX = torsional moment of inertiaIY = moment of inertia about the Y axisIZ = moment of inertia about the Z axisRY = radius of gyration about the Y axisRZ = radius of gyration about the Z axisSY = section modulus about the Y axisSZ = section modulus about the Z axisZY = plastic modulus about the Y axisZZ = plastic modulus about the Z axisOD = outside diameter of the circular hollow section (pipe)ID = inside diameter of the circular hollow section (pipe)THICK = thickness of the circular hollow section (pipe)YD = depth parallel to the Y axis (OD)YC = distance to the extreme fiber in the positive Y direction
(OD20)ZD = depth parallel to the Z axis (OD)ZC = distance to the extreme fiber in the positive Z direction
(OD20)ND = nominal depthGRPNUM = 10SHAPE = a number that indicates the profile shape
= 51 circular hollow section (pipe)
Properties Used by 00BS5950 GT STRUDL
Rev T 00BS59502 - 8 V2
This page intentionally left blank
GT STRUDL Parameters Used by 00BS5950
V2 00BS59503 - 1 Rev T
00BS59503 Parameters Used by 00BS5950
The parameters used by 00BS5950 code may be grouped into three generalcategories
1 System parameters2 Control parameters3 Code parameters
The system parameters are used to monitor the SELECT and CHECK commandresults Control parameters decide which provisions are to be checked and specifycomparison tolerances The third group referred to as code parameters are used to specifyinformation and coefficients directly referenced in the code With the notable exception ofCODETOL parameters of the second group are seldom used A knowledge of the systemand control parameters allows the user greater flexibility when using the 00BS5950 codeThe vast majority of parameters fall into the code category and have a direct bearing on00BS5950 code and the results it produces
For the categories described above the parameters used by 00BS5950 code arepresented below and are summarized in the Table 00BS59503-1 The system and controlparameters are discussed first followed by the code parameters