Design and Execution of Steel Structures and Composite Steel-concrete Buildings

AUG 2003 Draft Revision of ISO 8800

Design and execution of steel structures and

composite steel-concrete buildings

Procedure

Source: NBR 8800:1986CB-02: Brazilian Committee on ConstructionEC 02:NBR 8800:200 x - Design and construction of steel and composite structuresfor buildingsDescriptors: Design and construction. Steel structures. Steel and concretecomposite structures. Buildings.It is planned to cancel and replace the full NBR 8800:1986

Keywords: Design and implementation structures, structuressteel, composite steel-concrete structures, buildings 289 pages

AbstractForewordIntroductionObjective 12 Normative References3 Definitions, symbols and units4 General conditions of project5 Specific conditions for sizing steel elements6 Specific conditions for design of steel connections7 Specific conditions for design of steel-concrete composite members8 Specific conditions for design of composite joints9 Additional Considerations resistance10 Additional conditions of project11 limit states12 Manufacturing, assembly and quality controlAnnex A (Normative) - structural steel and metal bonding materialsAnnex B (Normative) - APAnnex C (Normative) - Recommended maximum displacementsAnnex D (Normative) - Bending Moment resistant characteristic of non-slender beamsAnnex E (Normative) - Local Buckling in compressed barsAnnex F (Normative) - Bending Moment resistant characteristic of slender beamsAnnex G (Normative) - shear force resistant characteristics including the effect of field driftAnnex H (Normative) - Length buckling by bending and twisting of compressed barsAnnex J (Normative) - Length buckling by bending the pillars of continuous structuresAnnex K (normative) - Normal force of elastic bucklingAnnex G (Normative) - Openings souls of beamsAnnex F (Normative) - FatigueAnnex C (Normative) - Particular requirements for bars of varying sectionAnnex E (Normative) - Best practices for implementing structuresAnnex Q (normative) - Beams composite steel-concreteAnnex R (normative) - Pillars mixed steel-concreteAnnex S (normative) - steel-concrete composite slabsAnnex T (normative) - steel-concrete composite connectionsAnnex U (normative) - Control of cracking in concrete composite beamsAnnex V (Normative) - Procedures for approximate elastic second-order analysis

Annex W (Normative) - Guidance for in floor vibrationAnnex X (Normative) - Orientation to vibrations due to wind

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NBR 8800 - Based Text Revision2

Foreword

ABNT - Brazilian Association of Technical Standards - is the National Standardization Forum.The Brazilian Standards, whose content is the responsibility of the Brazilian Committees (CB) andStandardization Bodies Sector (ONS), are prepared by Study Groups (EC),formed by representatives of the sectors involved including: producers,consumers and neutral (universities, laboratories and others).

The Brazilian Standard projects, developed through CB and ONS circulate to VoteNational ABNT among members and other interested parties.

This standard contains Annexes A, B, C, D, E, F, G, H, J, K, L, M, N, P, Q, R, S, T, U, V and Wnormative character.

This standard cancels and replaces in its entirety NBR 8800:1986 - Design and implementation ofsteel structures for buildings - Procedure.

This standard includes the steel-concrete composite columns, the steel-concrete composite slabs and linkscomposite steel-concrete, which were not foreseen in the NBR 8800:1986 - Design and implementation ofsteel structures for buildings - Procedure.

Introduction

For the development of this standard philosophy of the previous was maintained: NBR 8800, so that thethis standard set fits the general criteria governing the design ambient temperature and

implementation of structural steel and composite steel-concrete structures of buildings. Thus, it shouldbe complemented by other rules which establish criteria for specific structures.

Objective 1

1.1 This standard, based on the method of limit states, the general principles thatshould be followed in the design room temperature and execution, including inspection,structures of steel and steel-concrete composite structures for buildings in which:

- Profiles are rolled or welded steel;

- The elements of steel sections, plates and bars have thicknessless than 3 mm;

- Connections are bolted or welded or composite steel-concrete.

A related type of profile requirement does not apply to steel formwork slabs of composite steel-concrete and the shear connectors C profile cold-formed, and related to the thicknesssteel formwork at least mentioned, shims and filler plates.

The requirements of this standard apply only to steel profiles non-hybrids. Casehybrid profiles are used, the necessary adjustments must be made.

1.2 The steel-concrete composite structures, including steel-concrete composite joints, provided bythis Standard are those formed by components of steel and concrete, reinforced or otherwise,working together. The concrete may be of normal density or low density

except when some restriction is made in a specific part of the Standard.

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NBR 8800 - Based Text Revision 3

1.3 Profiles, rolled or welded shall be constructed obeying the Brazilian standardsapplicable. In the absence of such standards, it is permissible to use test results from the literaturespecialized or foreign standards or specifications, as provided in 1.7. Profilessoldiers can be fabricated by depositing weld metal or by electro-fusion.

1.4 The general principles in this standard apply to building structuresfor housing and commercial and industrial uses and public buildings, and the solutionsusual for bars and links. Also apply to structures pedestrian walkways.

1.5 To strengthen or repair of existing structures, the application of this standard may require studyand special adaptation to take into account the date of construction, type and quality of materialswere used.

1.6 The design of a structure made in accordance with this Standard should followcoherently all your criteria.

1.7 The responsibility for the design shall identify all applicable limit states, even thoughsome are not mentioned in this standard, and design the structure so that they do notare violated. For types of structures or situations not covered by this standard, or coveredsimply, it is permissible to use test results, professional literatureor foreign standards or specifications. In such cases, the responsibility for the project, ifnecessary, shall make the necessary adjustments to maintain the level of security provided bythis Standard. Additionally, tests may be performed following procedures areinternationally accepted, the relevant literature used should have recognition andacceptance by the international technical community and the standards and specificationsforeign should be internationally recognized and ready to use, being valid.

2 Normative References

The standards listed below contain provisions which, through reference in this text,constitute provisions of this Standard. Editions indicated were valid at the timethis publication. All standards are subject to revision, we recommend to those who performagreements based on this to verify the possibility of applying the most recent editions ofstandards listed below. ABNT has the information of the Brazilian Standards in forceany given time.

ASME B18.2.6: 1996 - Fasteners for use in structural applications

ASME B46.1: 2002, 2003 - Surface texture, surface roughness, waviness and lay

ASTM A6/A6M: 2001b - Standard Specification for General Requirements for Rolled StructuralSteel Bars, Plates, Shapes, and Sheet Piling

ASTM A108: 1999 - Standard Specification for Steel Bars, Carbon, Cold-Finished, StandardQuality

ASTM A307: 2000 - Standard specification for carbon steel bolts and studs, 60,000 PSI tensilestrength

ASTM A325: 2000 - Standard specification for structural bolts, steel, heat-treated, 120/105 ksiminimum tensile strength


ASTM A325M: 2003 - Standard Specification for Structural Bolts, Steel Heat Treated 830 MPaMinimum Tensile Strength [Metric]

ASTM A490: 2000 - Standard specification for steel heat-treated structural bolts, 150 ksiminimum tensile strength

ASTM A490M: 2000 Standard Specification for High-Strength Steel Bolts, Classes 10.9 and10.9.3, for Structural Steel Joints [Metric]

ASTM A568/A568M: 2003 - Standard Specification for Steel, Sheet, Carbon, and High-Strength,Low-Alloy, Hot-Rolled and Cold-Rolled, General Requirements for

ASTM A588/A588M: 2001 - Standard Specification for High-Strength Low-Alloy StructuralSteel with 50 ksi [345 MPa] Minimum Yield Point to 4-in. [100 mm] Thick

ASTM A668/A668M: 2002 - Standard Specification for Steel Forgings, Carbon and Alloy, forGeneral Industrial Use

ASTM A913/A913M: 2001 - Standard Specification for High-Strength Low-Alloy Steel Shapesof Structural Quality, Produced by Quenching and Self-Tempering Process (QST)

ASTM F436: 2002 - Standard Specification for Hardened Steel Washers

AWS A2.4: 1998 - Standard symbols for welding, brazing, and nondestructive examination

AWS A5.1: 2003 - Specification for carbon steel electrodes for shielded metal arc welding

AWS A5.5: 1996 - Specification for low-alloy steel electrodes for shielded metal arc welding

AWS A5.17: 1997 - Specification for carbon steel electrodes and fluxes for submerged arcwelding

AWS A5.18: 2001 - Specification for carbon steel filler metals for gas shielded arc welding

AWS A5.20: 1995 - Specification for carbon steel electrodes for flux cored arc welding

AWS A5.23: 1997 - Specification for low-alloy steel electrodes and fluxes for submerged arcwelding

AWS A5.28: 1996 - Specification for low-alloy steel electrodes for gas shielded arc welding

AWS A5.29: 1998 - Specification for low-alloy steel electrodes for flux cored arc welding

AWS D1.1: 2002 - Structural welding code - steel

ISO 898-1:1999 - Mechanical properties of fasteners made of carbon steel and alloy steel - Part1: Bolts, screws and studs

NBR 5000:1981 - Heavy plate steel, low alloy and high strength

NBR 5004:1981 - thin sheets of steel, low alloy and high strength


NBR 5008:1997 - Heavy plate and thick coils, low alloy steel, corrosion resistantAtmospheric, for structural use - Requirements

NBR 5920:1997 - thin cold and thin cold rolled coils sheets, low alloy steel, resistantatmospheric corrosion for structural use - Requirements

NBR 5921:1997 - Hot Tin plates and thin hot rolled coil steel, low alloy,resistant to atmospheric corrosion, for structural use - Requirements

NBR 6118:2003 - Design of concrete structures

NBR 6120:1980 - Loads for calculation of building structures

NBR 6123:1988 - Forces due to wind on buildings

NBR 6313:1986 - Part molten carbon steel for general use

NBR 6648:1984 - Heavy plate carbon steel for structural use

NBR 6649:1986 - Cold Plates thin carbon steel for structural use

NBR 6650:1986 - Hot thin sheets of carbon steel for structural use

NBR 7007:2002 - Steels for structural carbon and microalloyed use and general

NBR 7188:1984 - Mobile loads on road bridges and pedestrian walkways

NBR 7242:1990 - Part fused high-strength steel for structural purposes

NBR 8261:1983 - Tubular Profile, carbon steel, cold shape, with and without sewing sectioncircular, square or rectangular for structural uses

NBR 8681:2003 - Stocks and security structures

NBR 14323:1999 - Design of steel structures of buildings in fire

NBR 14762:2001 - Design of steel structures consist of cold formed profiles

Research Council on Structural Connections: 2000 - Specification for structural joints usingASTM A325 or ASTM A490 bolts

3 Definitions, symbols and units

3.1 Definitions

For the purposes of this International Standard, the following definitions:

3.1.1 Action: Any influence or set of influences can produce stress statesor deformation or rigid body motion in a structure.

3.1.2 share calculation: value per share used in the design of the structure.


3.1.3 Structural Steel: Steel produced based on the specification that classifies as structuraland establishes the chemical composition and mechanical properties.

3.1.4 Structural analysis: Determination of the effects of actions (normal force, shear force,bending moment, stress, displacement, etc..) bars and links.

3.1.5 rod: Component structure wherein the length is much greater than the dimensionsthe cross section.

3.1.6 weighting resistance: Value by which the resistance should be dividedcharacteristic to take into account uncertainties inherent in and get the same resistancecalculation (see 3.1.16).

3.1.7 Unlocked length: Length between two sections contained laterally (see3.1.18).

3.1.8 component: a constituent part of a profile as table, soul, tab, etc., or bar or whatever.another component of the structure.

3.1.9 limit states: states from which a structure no longer fulfills the purpose forwhich it was designed.

3.1.10 limit states: States that, by its occurrence, repetition or durationcause effects incompatible with the conditions of use of the structure, such as dislocationsexcessive, permanent deformations and vibrations. Also called limit statesservice.

3.1.11 ultimate limit states: corresponding to the ruin of the whole structure states, or part ofsame, by rupture, excessive plastic deformation, instability, etc..

3.1.12 element width: width of the flat portion of a constituent element of a profile,measured in the plane of the cross section.

3.1.13 Hybrid Profile: Profile elements whose components have steels with propertiesdifferent.

3.1.14 non-hybrid Profile: Profile elements whose components have the same steel.

3.1.15-thickness aspect ratio: ratio between the flat part of a constituent element ofa profile and thickness.

3.1.16 Calculation of resistance: Resistance value used in the design of the structure. Itobtained from the characteristic value of the material properties and the sections togetherwith a formula deduced rationally, based on analytical and / or experimental model, and

that represents the element's behavior in the limit state. Resistance calculation is equalthe characteristic resistance value divided by a coefficient that takes into account the uncertaintiesattached thereto.

3.1.17 characteristic strength: Value set from tests or some rational methodconnected to a resistance property.

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3.1.18 section contained laterally: Section compressed whose face has its lateral displacementprevented or impeded submit twist.

3.1.19 tubular section: circular or rectangular hollow section steel with uniform thickness,laminated or formed by cold working with continuous longitudinal weld.

3.1.20 characteristic value of shares: A value that quantifies the actions provided for in the rules of

actions and set the NBR 8681. A action with its characteristic value can be referredsimply as characteristic action.

3.1.21 conventional value of shares outstanding: arbitrated value for exceptional actions

by consensus between the building owner and government authoritieshave an interest in it.

3.2 Symbols

The symbols are used in this standard, regarding the steel structures and composite steel-concrete base is constituted by symbols (same size as the current text) and Symbolssubscribed.

The basic symbols used most frequently in this Standard are set out in3.2.1 and 3.2.2 subscripts symbols in the same length plain text, toeasy viewing.

The general symbology is found established in this subsection and the more specific symbologysome parts of this standard is presented in the relevant sections in order to simplifyunderstanding and therefore the application of established concepts.

3.2.1 Symbols basis

3.2.1.1 Roman Lowercase

the - Distance in general; distance between transverse stiffeners; region heightcompressed into slabs of composite beams; center to center distance between beams

thethe - Length of the openings

b - Width; effective width of the concrete screedbf - Effective widthbf - Table widthbfc - Width of the pillar table; width of the compressed table

bs - Width of stiffenerbw - The nominal size of the fillet weldd - Diameter in general; total height of the cross section; cylinder diameterdb - Diameter of the screw; outer diameter of the thread of threaded round bard

F- Distance from the upper surface of the concrete slab to the center of gravity of the area

the effective formworkd

h- Hole Diameter

dp - Pin diameterd

s- Distance from the center of gravity of the steel profile to the center of gravity

armorand - Eccentricity of loadingf - Voltage characteristic obtained by testing or resistant strain calculationfCD - Calculation of the actual resistance to compression

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fck - Characteristic compressive strength of concrete

fckb - Characteristic strength of the concrete low-density compressionfckn

- Characteristic strength of the concrete density normal to the compressionfctm - Average tensile strength of concretefdc

- Voltage resistant compression calculation on the upper surface of the concrete slab

fdt - Voltage resistant traction calculation table at the bottom of the steel beamfr

- Residual stressfu - Tensile strength of steel tractionfub

- Tensile strength of the bolt material or round bar threaded at

tractionfucs - Tensile strength of steel connectorfy - Yield strength of steel at normal stressfyF - Yield strength of the steel pan

fys - Yield strength of steel reinforcementfw - Minimum tensile strength of weld metalg - Drilling template; acceleration of gravityh - Overall height; Cell height; height of floorhc - Height of the concrete slab above the steel panhcs - Length of the pin after weldingh

f- Effective height

hF - Rib height of steel formworkhthe - Distance between the centroid of the tables; height of the openingshr - Height of the slab coatingh

t- Total height of the slab, including the concrete and formwork

kcs - Initial stiffness of the connectorsks - Initial stiffness of the bars of the armature; parameter associated tear

between holeskv - Coefficient for shear buckling of the soul

l - Length overall; length unlocked laterally lengthcylinder; buckling length of the column

l c - Clear distance, in the direction of the force, between the edge of the hole and the edge of the holeor adjacent the edge of the connected part

l n- Length of action of the force in the longitudinal direction of the beam

l w - Total length of the weldn - Number of connectorsNo ' - Number of connectors between the section with concentrated load and the adjacent section

of zero momentnb - Number of screwsncs - Number of shear connectors per ribnE - The ratio between the modulus of elasticity of steel and the elastic modulus

concretep - Tax width of the screwqRd - Calculating a resistance to shear connectorr - Radius of gyration; radiusrthe

- Polar radius of gyration of the gross section in relation to the center of shear

rx, Ry - Radii of gyration of the cross section with respect to x and y axes,respectively

s - Longitudinal spacing between two consecutive holes; minimum spacingbetween edges of openings

t - Overall thicknesstc

- Thickness of the concrete slabtF - Thickness of mold steel

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tf - Thickness of tabletfc - Thickness of the pillar table, thickness of the compressed tabletfcs

- The thickness of the board connector

t - Thickness of plate pulled

pts - Thickness of the stiffenertw - Web thicknessttoilets

- Web thickness of the connector

w - Size of the fillet leg strengthening or contourx

theY

the- Coordinates of the center of shear

yc - Distance from the center of gravity of the compressed portion of the steel beam sectionto the upper surface of this beam

yLNP - The neutral axis positionyp - Distance from the neutral axis of the section laminated to the top surface of the steel beam

ys - Distance from the center of gravity to the center of the steel shear beamyt - Distance from the center of gravity of the compressed portion of the steel beam section

to the upper surface of this beam

3.2.1.2 Roman Uppercase

The - General areaThethe - Cross-sectional area of the steel profileThe

ac- Compressed area of the steel section profile

Theat - Pulled area of the steel section profileTheb - Gross area of boltThebe - Resistant area or effective area of a bolt or threaded round barThe

c- Cross-sectional area of the connected elements; cross-sectional area

ConcreteThecs - Cross-sectional area of the connectorTheand - Effective net cross-sectional areaThef - Effective area

TheF - Area of mold steelThef - Area of the tableThefe - Effective area of table pulledThefg - Floor area of tensioned or compressed table

Thefn - Net area of tensioned or compressed tableThefnt - Net area of the pulled tableTheg - Gross cross-sectional areaTheMB - Theoretical area of the face meltingThe

n- Net area

Thes - Total transverse reinforcement area per unit length, includingadditional equipment and any equipment provided to bending of the slab; areacross section of the longitudinal reinforcement

Thesa - Area of additional armorThew - Effective area of shear; effective area of the weld; area of the soulC

b- Modification factor for bending moment diagram nonuniform

Cd - Resistance calculation of the compressed thickness of the concrete slabC 'd - Resistance calculation of the compressed portion of the steel profileCm - Equivalence of momentsCpg - Coefficient used in the calculation of slender beams

Cred - Reduction factor of the strength of the shear pin type connector withhead

Ct - Reduction coefficient used in the calculation of the effective net area

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Cv - Coefficient of shearCw - Constant warping of the cross sectionD - Outer diameter of tubular circular section; OD

eyelet headD

the- Diameter of apertures

E - The tangent modulus of elasticity of steel

Ec - Initial secant modulus of elasticity of concrete at the limit of resistancecompression

E 'c

- Modulus of elasticity of concrete reduced due to the effects of shrinkage and

creepEcb - Initial secant modulus of elasticity of the concrete in the low density limit

Compressive strengthEcn - Secant modulus of elasticity at normal density concrete limit

compressive strengthEs - Tangent modulus of elasticity of steel reinforcement of concrete

FG - Characteristic value of permanent actionsFQ - Characteristic value of variable actionsFQ, exc - Characteristic value of the outstanding sharesG - Modulus of transverse elasticity of steel, equal to 0.385 E; characteristic action

permanent; center of gravity of the bar

I - Moment of inertiaIthe

- Moment of inertia of the cross section of the steel profileIc - Moment of inertia of the cross section of the concreteIf

- Moment of inertia effective

Ip - Moment of inertia of the pillarIs

- Moment of inertia of the cross section of the reinforcement of concreteIT - Moment of inertia of uniform twisting of the steel sectionItr - Moment of inertia of the homogenized composite section

Iv - Moment of inertia of the beamIx, Ry - Moments of inertia of the cross section with respect to x and y axes,

respectivelyK - Buckling coefficient used in sizing bars

compressedL - Or length will generallyL ' - Distance between the sections of maximum positive and negative momentsLb - Length unlocked

Lcs - Length of the U profile connectorLand - Length of the stretch of positive moment; distance between points

zero moment

LF - Will theorist steel pan toward the ribsLp - Height of the floor for a pillarLs - Shear spanL

t- Length of the input strength of concrete

Lv - The beam willM - Bending momentMthe - Resistant bending moment calculation of steel girder isolatedMcr - Bending moment of elastic buckling

Mpl- Bending moment plasticizing section

Mr - Bending moment corresponding to the onset of flowMRd - Resistant bending moment calculation

MRd, pl- Bending moment resistant plasticizing calculation

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MRd x; MRd, y - Resistant to bending moments calculated respectively around the axes xey cross section

MRk

- Characteristic bending moment resistant

-Rd

M - Resistant bending moment calculation in the region of negative moment

-dist,Rd

M - Resistant bending moment calculation in the region of negative moment, for

limit state of lateral buckling Distorted-- M;M - Resistant bending moments for calculating the left and right ends,

dir,Rdesq,Rd respectively, module of composite beams subjected to negative moment incase of continuous beams, or mixed connections in the case of semicontinuous beams

-Rk

M - Bending moment resistant characteristic in the region of negative moment

MSd - Bending moment calculation requestorMSd, G '; MSd, G - Applicants bending moments calculation due to active actions

respectively before and after the strength of concrete reaches f 0.75 ckMSd, max - Maximum bending moment calculation requesting the bar, determined by

the analysis of the first orderMSd, q - Bending moment calculation in requesting biapoiada beam function of the abscissa x

MSd, x; MSd, y - Requesting bending moments of calculation respectively about axesx and y of the cross section

N - Length of action of the force in the longitudinal direction of the beam, the number ofcycles of variation of tension during the useful life of the structure

Nc, R

- Normal force resistant compression calculation

Nand - Normal force of elastic buckling

Npl- Normal force corresponding to the flow cross section

NRd - Tough normal force calculation

NRd, pl- Tough normal force calculation of the cross section to the total lamination

NSd

- Normal force requestor compression calculationNt, Rd - Normal force resistant traction calculationN

y- Normal force corresponding to the flow of the compression section

effective crossP - Thread pitchPdub - Calculating a resistance screw, taking into account the shear and

contact pressure in the holes

PSRD - Calculation of resistance of the armature barsQ - Variable action; coefficient of local buckling; additional traction force

caused by the leverageQthe; Qs - Coefficients that take into account the local buckling of AA and AL elements,

respectivelyQRd - Sum of the individual resistance calculation, q Rd, The connectors

shear section located between the maximum positive moment and the sectionadjacent zero moment

Q 'Rd - Sum of the individual resistance calculation, q Rd, The connectorsshear located between sections of maximum positive and negative moments

R - Fillet radius between the head and the body of the lugRd - Resistance calculationRFIL - Reduction factor for joints up only a couple of fillet weld

transverseR

PJP- Reduction factor for welds notch partial penetration

RRd - Resistant request calculationRRk - Resistant feature requestSd - Request for calculation

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Tb - Minimum strength prestressing screwTd - Calculation of resistance region pulled the steel profileT

Rds- Sturdy traction force calculation in the longitudinal reinforcement bars

TSd - Requesting traction force calculation on the screw without leverage

Vpl- Shear force corresponding to yielding of the soul shear

VRd - Resistant shear force calculation

VRdl- Sturdy longitudinal shear force calculation of composite slabs

VRd, p

- Resistant shear force calculation to puncture caused by a load

concentratedV - Sturdy vertical shear force calculation of composite slabs

Rd, vVRk - Shear resistant featureV

Rkt- Shear resistant characteristics including the effect of field drift

VSd - Shear strength calculation requestorV

Sd, q- Shear strength calculation in requesting biapoiada beam function of the abscissa x

W - Minimum modulus of section of elastic strength relative to bending axisWthe - Resistance of the elastic modulus of the steel section profileWc, Wt - Elastic modulus of resistance of the tablet and pulled next to the section,

respectively, relative to the bending axis

Wf - Effective elastic modulus of resistanceWtr - Modulus of the homogenized elastic resistance section in composite beams

Wx, Wy - Elastic resistance modules with respect to x and y axes, respectivelyZpa - Module plastic resistance of the steel profile sectionZpc - Module plastic resistance of the concrete sectionZps - Module plastic resistance of the armature of the concrete section

3.2.1.3 Greek Lowercase

- Related to sizing the compression curve coefficient; coefficientrelated to the effect Rsch

- Reduction factor

the - Coefficient of thermal expansion of steel

cn - Coefficient of thermal expansion of the normal density concrete

vm - Coefficient which takes into account the rotation capacity required for connection - Contributor steel, scroll, arrowcs - Specific deformation of free shrinkage of concrete

smu - Deformation of the concrete armor involved

su - Strain corresponding to the tensile strength of the armor isolated

sy - Strain corresponding to the yield strength of the armor isolated

- Diameter of the reinforcement bars - Weighting coefficient of resistancethe - Specific weight of steel; weighting the strength of steel

c

- Specific weight of concrete; weighting the resistance of the

concretecb - Specific weight of the concrete of low density

cn

- Specific weight of concrete normal density unarmoredcna - Specific weight of normal density concrete with reinforcement

cs - Weighting coefficient of resistance of the connector

g - Weighting of permanent actions

q

- Weighting of variables sharesr - Weighting coefficient of stiffness

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s - Weighting the strength of steel armor

z - Coefficient for setting the order of magnitude of the horizontal displacements

- Slenderness parameter

the - Reduced slenderness ratio

p - Slenderness parameter corresponding to the lamination

r - Slenderness parameter corresponding to the onset of yield

rel- Relative slenderness

- Average coefficient of friction

the - Poisson's ratio of structural steel

cn - Poisson's ratio of concrete normal density

cb- Poisson's ratio of concrete of low density

- Reduction factor associated with the compressive strengthdist - Reduction factor for lateral buckling distortion of the cross section with

- Tension in general

cr- Tension buckling

c, R - Tension buckling

and - Critical elastic buckling stress

Rd

- Resistant strain calculation

Sd - Requesting tension calculation

SR - Permissible limit for the range of variation of stresses

TH - Permissible limit of range of voltages, for an infinite number ofrequest cycles

Rk - Voltage characteristic shear

oj - Factor combination of variable actions

1j

; 2j

- Utilization factors of

3.2.1.4 Greek Uppercase

us - Deformation capacity of the armature bars

ui - Deformation capacity of the connection

- SUM

3.2.2 Symbols subscribed

3.2.2.1 Roman Lowercase

the - Steel

b - Screw; threaded round barc - Concrete; compression

cb - Low density concretecn - Normal density concrete

cs - Shear connectord - Calculationand - Elasticf - Effective

f - Tableg - Gross

i - Order numbern - Net

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pl - Laminations - Armor

t - Tractionu - Break

w - Soul; solderx - On the x-axisy - Runoff; relative to the y axis

3.2.2.2 Roman Uppercase

F - Mold steelRd - Resistant calculation

Rk - Resistant characteristicSd - Requesting calculation

3.3 Units

Most of the expressions presented in this standard is dimensionless, so they should beemployed quantities with consistent units. When units are mentioned, they areaccording to the International System of Units.

4 General conditions of project

4.1 General

4.1.1 The fully or partially executed works with steel frame or mixed structuresteel-concrete must comply with elaborate design in accordance with this standard, underresponsibility of a legally qualified professional with experience in design and construction

these structures, which must be manufactured and constructed by competent companies andkeep running under competent supervision.

4.1.2 It is understood as the set of design calculations, drawings, specifications and manufacturing

Mounting structure.

4.2 Design drawings

4.2.1 The design drawings must be executed in an appropriate scale for the level of

desired information. Should contain all the necessary data for the detailedstructure for the implementation of assembly drawings and the design of foundations.

4.2.2 The design drawings shall indicate which standards were used and givespecifications for all structural materials used.

4.2.3 In addition to the materials, data must be reported to the actions of calculation adopted and

calculation of internal forces to be resisted by bars and links, when required toproper preparation of fabrication drawings.

4.2.4 For connections with high strength bolts, the design drawings shall indicate whether the

tightening will be normal or initial prestressing, and in the latter case, if the bolts to workshear, if the connection is friction or contact.

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4.2.5 Welded connections should be characterized by appropriate symbology containingto complete its execution information in accordance with AWS A2.4.

4.2.6 In the case of industrial buildings, shall be made on the design drawingsschema location of the most important actions resulting from equipment that will besupported by the structure, the values of these actions and, eventually, the data for considerationdynamic effects.

4.2.7 Where necessary, the conditions should be considered for installation and indicated

provided lifting points and weights of the parts of the structure. Should be taken into accountcoefficients appropriate for the type of equipment to be used in assembling impact.

In addition, must be given the positions that are temporarily occupied bymain or auxiliary equipment mounting on the structure, mooring positioncables or spies, etc.. Other situations that may affect the safety of the structure should alsobe considered.

4.2.8 In cases where the lengths of the frame pieces may be influenced by

temperature variations during assembly, must be given the variation rangesconsidered.

4.2.9 should be indicated in the design drawings of the contraflechas beams soul filled andlattice.

4.3 Drawings manufacturing

4.3.1 The fabrication drawings should translate faithfully to the factory, the informationcontained in the design drawings, giving complete information to manufacture all

Component elements of the structure, including materials and specifications,lease, type and size of all bolts, welds factory and field.

4.3.2 Where necessary, it should be indicated on the drawings the execution sequence of links

important to avoid the appearance of excessive residual stresses or warping.

4.4 Assembly drawings

The assembly drawings shall indicate the main dimensions of the structure, brand of parts,

dimensions of bars (when required for approval), elevations of lower faces of platesbase pillars, all dimensions for detail placement of anchors and other

information necessary for the assembly of the structure. Should be clearly indicated allpermanent elements or essential to the integrity of the temporary structure partially

Built. Also applies here to the provisions in 4.3.2.

4.5 Materials

4.5.1 Introduction

4.5.1.1 The structural steel and metal materials approved for use by this connectionStandard 4.5.2 and are cited in the concrete and steel for armor in 4.5.3.

4.5.1.2 Full details of the materials listed in 4.5.2 and 4.5.3 are thecorresponding specifications and more information on the structural steels and materialsmetal binding are in Annex A.

Page 16


4.5.2 Structural Steels and metal bonding materials

4.5.2 Steels 1 for profiles, rods and plates

4.5.2.1.1 steels approved for use in this standard for profiles, rods and plates are those withstructural qualification ensured by Brazilian standard specification or standard or foreign,provided they have characteristic resistance maximum flow 450 MPa and relationship betweenresistance characteristics to rupture and drain not less than 1.18.

4.5.2.1.2 is still allows the use of other structural steels since they have resistance

feature to the maximum flow 450 MPa, the relationship between resistance characteristicsrupture and drain not less than 1.25 and that the responsibility for the project to analyze the

differences between these grades and specifications mentioned in 4.5.2.1.1 and mainlythe differences between the sampling methods used in determining its propertiesmechanical.

4.5.2.1.3 It is recommended not to use structural steels without qualification. However, this is tolerateduse, provided free of surface imperfections, only minor parts and details

importance, where the properties of steel and its weldability not affect the resistance ofstructure. If this type of steel is used, should not be adopted in the project higher values180 MPa and 300 MPa for the characteristic flow resistance and resistance

feature at break, respectively.

4.5.2.2 Steel castings and forgings

Where the use of fabricated structural elements with molten steel is necessary orwrought Brazilian standards related to the issue or standard or must be obeyed

foreign specification.

4.5.2.3 Bolts

The screw steel low carbon must meet ASTM A307 or ISO 898Class 4.6, the high-strength bolts, including nuts and washers appropriatehardened, shall comply with ASTM A325, ASTM A325M or ISO 898 Class 8.8 andscrews alloy steel hardened and tempered shall meet ASTM A490, ASTM A490M or

898 ISO Class 10.9.

4.5.2.4 Electrodes, welding wire and flux

4.5.2.4.1 The electrodes, wires and fluxes for welding shall meet the following

Specifications:

a) for mild steel electrodes, coated, for electric arc-welding: AWS A5.1;

b) electrodes for low alloy steel, coated, for electric arc-welding: AWSA5.5;

c) for bare mild steel electrodes and flux for submerged arc welding: AWS A5.17;

d) for mild steel electrodes for electric arc welding with shielding gas: AWS

A5.18;

Page 17


e) for mild steel electrodes for arc welding with flux in the core: AWS A5.20;

f) to bare steel electrodes, low alloy and flux for submerged arc welding: AWSA5.23;

g) for low alloy electrodes for arc welding with shielding gas: AWS

A5.28;

h) for low alloy electrodes for arc welding with flux in the core: AWS A5.29.

4.5.2.4.2 Approval of specifications for electrodes cited in 4.5.2.4.1 is takenregardless of the requirements for impact tests which in most cases are not

required for buildings.

4.5.2.5 Shear Connectors

4.5.2.5.1 The pin type connectors steel with heads shall meet the requirements of Chapter 7of AWS D1.1: 2002.

4.5.2.5.2 The steel shear connectors in the profile laminate U must comply with 4.5.2.1.

4.5.2.5.3 The steel shear connectors C profile cold-formed must obeyrequirements of ISO 14762.

4.5.2.6 Steel mold of the slab

The steel mold of the slab and its coat must comply with Section S.7 (AnnexS).

4.5.2.7 Identification

The materials and products used in the structure must be identified by their specification,

including type or grade, if applicable, using the following methods:

a) quality certificates provided by plants or producers dulyrelated to the products supplied;

b) legible markings applied to the material by the producer, in accordance with the standards of

corresponding standards.

4.5.2.8 General Mechanical properties

For calculation purposes should be adopted for steels listed, the following valuesMechanical properties:

a) tangent modulus, MPa205000E = ;

b) Poisson's ratio, 30the

= ;

c) coefficient of thermal expansion, 16the

C1012 -- = ;

Page 18


d) specific weight, 3the

m/kN77= .

4.5.3 Concrete and steel reinforcement

4.5.3.1 The properties of normal density concrete should conform to NBR 6118. So

the characteristic compressive strength of concrete of this type should be between 10 MPa and50 MPa, and the following values should be used:

a) initial secant modulus of elasticity in compression yield strength,

ckncnf4760E = , Where E cn f ckn are given in megapascals (f ckn is the resistance

characteristic of normal density concrete compressive);

b) Poisson's ratio, 200cn

= ;

c) coefficient of thermal expansion, 15cn

C10 -- = ;

d) specific weight, 3cn

m/kN24= in concrete without armor and 3cna

m/kN25= on

reinforced concrete.

4.5.3.2 The properties of low density concrete must comply with standard orrelevant domestic or foreign specifications. This type of concrete should have specific weight

at least 15 kN / m 3 unarmored, and the modulus of elasticity in the initial drying limitcompression strength in megapascals should be taken equal to:

ckb5,1

cbcbf5,40E =

where:

cb

is the specific weight of the concrete of low density, without reinforcement in a quilonewton

cubic meter;

fckb is the characteristic strength of the concrete low-density compression inmegapascals.

For Poisson's ratio, can be used value of 0.2 (equal to the density of the concrete

normal). The thermal expansion coefficient must be determined by specific study.

4.5.3.3 this standard, the secant modulus of elasticity, compressive strength characteristic,Poisson's ratio, thermal expansion coefficient and the specific weight of the concrete will be

always represented by E cF ck, c, c and c, Respectively. So if the concrete is of

Normal density must be takencnccnccnccknckcnc

and,,ff,EE ===== on

concrete without reinforcement orcnac

= for reinforced concrete; and if low density

cbccbccbcckbckcbcand,,ff,EE ===== for the concrete without reinforcement or

cbac=

for reinforced concrete.

4.5.3.4 The properties of steel reinforcement shall conform to NBR 6118.

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4.6 Basis for sizing

The method of states limits used for sizing the components of a

structure requires that no applicable limit state is exceeded when the structure issubject to all appropriate combinations of actions. When the structure no longer meets

objectives for which it was designed, one or more states limit has been exceeded. The statesultimate limits are related to the safety of the structure subject to more combinationsunfavorable actions of calculation provided for in the lifetime, in a transient situation or

When acting exceptional action. The limit states are relatedperformance of the structure under normal service conditions.

1 4.6 Dimensioning for ultimate limit states

4.6.1.1 The design for the ultimate limit states implies that the request

Tough for calculating each component or assembly of the structure equal to or greater than theactive calculation request. In some situations, it is necessary to combine through

expressions of appropriate interaction terms reflecting relations between active requestscalculation and resistant requests from different calculation. Each sturdy request calculation, S Rd,

is calculated for the applicable limit state and is equal to the quotient of the sturdy requestcharacteristic S

RkAnd the weighting coefficient of resistance. Resistant requests

S characteristics Rkand the coefficient of resistance are given in sections 5, 6, 7 and 8, depending

ultimate limit state. Other security-related checks are in Section 9.

4.6.1.2 The calculation of active request must be determined for combinations of actionscalculation that are applicable, in accordance with 4.7.

4.6.2 Scaling to limit states

The structure should be checked for serviceability limit states in accordance with the requirements

Section 11.

4.7 Actions and combinations of actions

4.7.1 Values and classification

The actions to be taken in the design of structures and their components are set

by Brazilian standards NBR 6120, NBR NBR 6123 and 7188, or other applicable standards, andalso in Annex B of this Standard. According to NBR 8681, these shares are classified

according to their variability in time, in the following three categories:

- F G: Permanent actions - actions resulting from the own weight of the structure and allComponent elements of the building (floors, tiles, permanent walls, coatings andfinishes, fixed equipment, etc..), which are called actionsDirect permanent, and actions from effects of support settlements, retractionmaterials and prestressing, which are called indirect permanent actions;

- FQ

Varying actions - actions resulting from the use and occupation of the building (due to actions

overloads on floors and roofs, equipment and movable partitions, etc..), pressurehydrostatic, buoyancy of earth, wind, temperature variation, etc..;

- F Q, exc: Exceptional actions - actions resulting from fires, explosions, shocksvehicles, seismic effects, etc..

Page 20


In the rules of combinations of actions for ultimate limit states and use, given4.7.2 and 4.7.3 respectively, actions must be taken with their characteristic values

according to NBR 8681. Exceptional actions can be taken to their valuesexceptional standard.

4.7.2 Combinations of actions for ultimate limit states

4.7.2.1 Combinations of actions for ultimate limit states, according to NBR 8681,are:

a) normal combinations latest:

)F(F)F(Qjoj

n

2jqj1Q1q

m

1iiGgi

++

==

b) past or special construction (temporary situation) combinations:

)F(F)F(Qjf,oj

n

2jqj1Q1q

m

1iGigi

++

==

c) exceptional recent combinations, except for the case where the outstanding actionFire follows (see 4.7.2.2):

)F(F)F(Qjf,oj

n

qjexc,Q

m

Gigi++

1j1i ==

Where:

FGiare the permanent actions;

FQ1variable is considered as the main action in the normal combinations, or as

leading to transient situation in special combinations or building;

FQjother variables are the shares;

FQ, excis the exceptional action;

gi are the weighting coefficients of permanent actions, provided in Table 1 (for

further information should be consulted to NBR 8681);

qj are the weighting coefficients of the variables shares, provided in Table 1 (for

further information should be consulted to NBR 8681);

ojfactors are the combination of variables that can act concomitantly actions

with the main variable action F Q1Under normal combinations, as shown in Table 2;

j, f factors are effective combination of live loads that may act

concurrently with the main variable action FQ1

During the transitional situation, or

with exceptional action F Q, exc. The factor j, f factor is equal to ojadopted in combinations

Page 21


normal except when the main action F Q1or exceptional action F Q, exchave a timevery small role, in which case

j, fmay be taken equal to the corresponding

2(Table 2).

Table 1 - Weighting coefficients actions

Permanent actions ( g)1) 3)

Direct

CombinationsOwn weightstructures

metal

Weightownstructures

pre-molded

Own weight ofstructures

molded insite andelements

constructiveindustrialized

Own weight ofelements

constructiveindustrializedwith additions "in

loco "

Own weightelementsconstructiveand in general

equipment

Indirect

Normal1.25

(1.00)1.30

(1.00)1.35

(1.00)1.40

(1.00)1.50

(1.00)1.20(0)

Special orConstruction

1.15(1.00)

1.20(1.00)

1.25(1.00)

1.30(1.00)

1.40(1.00)

1.20(0)

Exceptional1.10

(1.00)1.15

(1.00)1.15

(1.00)1.20

(1.00)1.30

(1.00)0

(0)

Shares variables (q)1) 4)

Effect of temperature 2) Wind actionOther variables actionsincluding those arising

the use and occupation

Normal 1.20 1.40 1.50

Special orConstruction

1.00 1.20 1.30

Exceptional 1.00 1.00 1.00NOTES:1)The values in parentheses correspond to the coefficients for permanent actions favorable to safety;

variables and exceptional actions favorable safety should not be included in the combinations.2)The temperature effect mentioned does not include the generated equipment, which must be regarded as action

resulting from the use and occupancy of the building.3)Direct permanent actions that are not conducive to security may optionally be considered all

grouped with weighting equal to 1.35 when the stock variables arising from the use and occupationis equal to or greater than 5 kN / m2Or 1.40 when it is not.

4)If the direct permanent actions that are not conducive to safety are grouped variables actions that do notare favorable safety can optionally also be considered all grouped with coefficientequal weighting of 1.40 when the variables arising from the use and occupation shares are equal to or greater than 5kN / m2Or 1.50 when it is not (even in this case, the temperature effect can be seenseparately, with its own weighting).

4.7.2.2 Combinations of exceptional past actions to ultimate limit states infire situation should be determined according to NBR 14323.

4.7.3 Combinations of actions for serviceability limit states

In the combinations of actions for serviceability limit states are considered all actionspermanent, including permanent deformation imposed, and the actions variables

corresponding to each of the types of combinations as follows:

Page 22


a) quasi-permanent combinations of use (combinations that may act duringmuch of the lifetime of the structure, the order of half of that period):

)F(FQjj2

n

1j

m

1iGi

+

==

b) frequent use combinations (combinations that repeat oftenduring the lifetime of the structure, of the order of 10 5 times 50, or having

total duration equal to a not insignificant part of that period, of the order of 5%):

)F(FFQjj2

n

2j1Q1

m

1iGi

++

==

c) use of rare combinations (combinations that can act at most a fewtime during the life of the structure):

)F(FFQjj1

n

2j1Q

m

1iGi

++

==Where:

FGiare the permanent actions;

FQ1is the main variable action of the combination;

1jFQjare the common values of the action;

2j

FQj

are the quasi-permanent values of the action;

1j, 2jfactors are used as table 2.

Table 2 - Factors combo and use factors

Share oj1)

1j

2j

Uniform temperature variations compared to the local average annual 0.6 0.5 0.3Dynamic pressure of the wind on structures in general 0.6 0.3 0Actions resulting from the use and occupation:- No predominance of equipment that remain fixed for long

periods of time or high concentrations of persons- With predominance of equipment that remain fixed for long

periods of time or high concentrations of persons- Libraries, archives, warehouses, workshops and garages

0.5

0.70.8

0.4

0.60.7

0.3

0.40.6

Moving loads and their dynamic effects:- Beams bearing crane- Pedestrian Walkways

1.00.6

0.80.4

0.50.3

Note:

1)The coefficients ojmust be accepted as 1.0 shares for variables of the same nature of the variable actionmain F Q1.

Page 23


4.7.4 Cases not covered in this Standard

For cases of combinations of actions related to the ultimate limit states or usenot covered in this standard shall be in compliance with the requirements of ISO 8681.

4.8 Stability and structural analysis

4.8.1 General

4.8.1.1 This subsection deals with the analysis and stability of structures. Thus, 4.8.2 aredefined braced and not braced structures and provided guidelines for assessmenttheir stability, and 4.8.3, general rules are presented for structural analysisfor verification of ultimate limit states.

4.8.1.2 Structural analysis for verification of limit states must be ugly

as stipulated in this standard parts dealing with the issue. If analysis is donesecond order, should follow the procedures given in 4.8.3, but using the

combinations of actions appropriate for these types of limit states.

4.8.2 Structural Stability

4.8.2.1 General

The stability of the structure as a whole and must be guaranteed for each component element,

considering the significant actions of the deformed structure effects.

4.8.2.2 braced structures

4.8.2.2.1 In those trusses and structures whose lateral stability is guaranteed by systemsuitable bracing, shear walls structural or other meansequivalents, here classified as braced structures, the buckling coefficient K tobe used in the design of compressed bars, provided the requirements of

4.8.5, can be taken equal to 1.0 unless it is demonstrated by the analysis of the structure, or

if applicable, by the use of attachments H and J, which values less than 1.0 may be used. Casethere is a rigid connection between beams and columns, reducing the stiffness adjustments of pillars requested outsideelastic allowed.

4.8.2.2.2 A second-order analysis that includes the initial imperfections of the structure,as 4.8.3, can be used in place of the requirements presented in 4.8.5.

4.8.2.2.3 vertical bracing system must be determined by structural analysis andbe adequate to prevent buckling and maintain the stability of the structure, including resistingthe destabilizing effects of gravity loads on pillars and other structural components

vertical unable to withstand lateral forces, combinations of shares for calculationstipulated in 4.7.

4.8.2.2.4 Lets consider that the internal and external structural walls and slabsand floor covering part of the vertical bracing system providedappropriately sized and connected to the structure. Columns, beams and diagonal when used

as part of the vertical bracing system can be considered as barsa vertical trellis swing study of buckling and lateral stability of the structure.

Page 24


The axial deformation of all the bars of the vertical bracing system must be includedthe study of lateral stability.

4.8.2.3 Structures not braced

4.8.2.3.1 In structures where the lateral stability depends on the flexural rigidity of beams and columnsrigidly connected to each other, here classified as not braced structures, the coefficient

K buckling of compressed bars should be determined by structural analysis or, ifapplicable, as Annex J. The destabilizing effects of gravity loads on pillars and

other vertical structural members without ability to withstand horizontal forcesshould be considered in the analysis. Adjustments reducing the stiffness of pillars requested outside

elastic allowed.

4.8.2.3.2 If analysis of the structure is taken directly into account the effects ofinitial imperfections of the structure as a whole, as 4.8.4.1, 4.8.4.2 and 4.8.4.3 can beconsider the buckling coefficient K equal to 1.0.

4.8.2.3.3 In determining the effects of the strength of the instability should be includedstructural and axial deformation of the pillars, combinations of shares for calculating stipulatedin 4.7.

4.8.3 Structural Analysis

4.8.3.1 Types of analysis and second order effects

4.8.3.1.1 The internal forces calculation in bars and links the structure to checkthe ultimate limit states, must be obtained through elastic analysis, as 4.8.3.1.2,except when permissions for other types of analysis are explained in parts of thisStandard.

4.8.3.1.2 Elastic second-order analysis must be rigorous, as 4.8.3.1.3, forcombinations appropriate actions listed in 4.7. Still admits the use of elastic analysisestimated and approximate second order, described in 4.8.3.3 and 4.8.3.4 respectively,depending on the sensitivity of the structure to horizontal displacements (see 4.8.3.2) and since

the conditions shown are met. In any analysis must take intoaccount the effects of initial imperfections of the structure as a whole, according to

4.8.4.

4.8.3.1.3 The term rigorous elastic second-order analysis that in which the equationsequilibrium is established in the deformed configuration of the structure. This type of analysisusually has a high degree of complexity, requiring a strategy of numerical resolutioninvolving iterative procedures, and allows properly account the overall effects andlocal second order, defined in 4.8.3.1.4 and 4.8.3.1.5 respectively. Its validity in

However, it is limited in principle to cases in which the second order effects do not exceed40% analysis of the first order. If this occurs, we must increase the rigidity of the structure to

reduce the horizontal displacements, or place an elastoplastic analysis of second order, theunless it is demonstrated that the stresses acting, with the combinations of actions of calculation,

as 4.7, even if including the residual stresses do not exceed the yield strengthsteel in any cross section.

4.8.3.1.4 Submitted to vertical and horizontal forces, structures moving horizontally.

Global second order effects, also called P- effects are the answers

Page 25


arising from horizontal displacements on the ends of the bars (rotations ofropes), which are obtained by establishing equilibrium in the deformed configurationstructure represented by the polygon defined by the strings of the various bars.

4.8.3.1.5 The local second order effects, also called P- effects are the answersresulting displacement of the deformed configuration of the structure of each barsubject to the normal force in relation to the position of the respective string.

4.8.3.2 Structures little too sensitive to horizontal displacements

4.8.3.2.1 The structure is considered to be very sensitive to horizontal displacements are, in alltheir floors, the coefficient B 2Given by the following expression, not exceed 1.1:

-

=

Sd

Sdoh2

H

N

h1

1B

Where:

Sd

N is the sum of the normal forces applicants calculation across all pillars and

resistant to vertical loads other elements (including the pillars and other elements thatnot belong to the system resistant to horizontal forces), considered on the floor;

oh is the horizontal relative displacement (between floors);

HSdis the sum of all horizontal forces producing displacement calculation

horizontal on the floor considered;

h is the height from the floor (wheelbase beams).

4.8.3.2.2 The structure is considered very sensitive to horizontal displacements are in the

least one of his stories, the coefficient B 2 is greater than 1.1.

4.8.3.3 Analysis estimated second order

4.8.3.3.1 The rigorous elastic second-order analysis, depending on the sensitivity of the structure

the horizontal displacements can be replaced by an analysis estimated, taking intoaccount the effects of initial imperfections in accordance with 4.8.4, with the following rules:

- Insensitive to the horizontal displacements global structures for secondaryorder can be neglected and the local second-order effects should beconsidered a simplified form as 4.8.3.3.2;

- In very sensitive to horizontal displacements structures with the highest coefficient B 2,

taking all floors not exceeding 1.3, the second global and local effectsorder can be considered a simplified form as 4.8.3.3.3.

4.8.3.3.2 In some structures sensitive to horizontal displacements, the bending momentrequestor calculation, M SdIncluding the local second-order effects, can be determinedby:

Page 26


1Sd0SdMBM =

Where:

B0 is a coefficient given by:

1

N

N1

CB

and

Sd

m0

-

= If the requester normal force calculation on the bar, N Sd, Is the

compression;

1B0

= If the normal force on the bar requesting calculation, NSd, For traction.

Nand

is the normal force of elastic buckling of the bar in the plane considered, calculatedbased on their buckling length, according to 4.8.2;

Cmis an equivalence of moments, given by:

- If no transverse forces between the ends of the bar in the planebending:

2

1m M

M400600C -=

being21

MM the ratio between the smallest and the largest bending moments of

applicants in calculating the bending plane, the supported ends of the bar,taken as positive when the curvature and moments cause reverse

cause negative when a single curve;

- If lateral forces between the ends of the bar in the planebending, the value of C

mshould be determined by rational analysis or be taken

in the case of 0.85 bar with both ends embedded and 1.0in other cases.

MSd 1requestor is the bending moment calculation at bar, obtained by structural analysiselastic first order.

The other internal forces to be used in the verification of ultimate limit states canbe those obtained directly by first-order elastic analysis.

4.8.3.3.3 In very sensitive to horizontal displacements structures with the highest coefficient B 2not more than 1.3, a simplified solution for the assessment of the overall effect of secondorder consists in determining the internal forces based on elastic analysisfirst order, multiplying the actions that cause horizontal displacements of thefound by combining 0.95 times higher B 2. The values obtained for normal forces andcutting shall be used in the verification of ultimate limit states, but additionally therequestor bending moment calculation to be used must also include the local effects ofsecond order, is given by:

Page 27


2Sd0SdMBM =

Where:

B0 should be determined as 4.8.3.3.2;

MSd, 2requestor is the bending moment calculation obtained from the above analysis.

4.8.3.3.4 In very sensitive to horizontal displacements structures with the highest coefficient B 2greater than 1.3, considering all the floors, the only option allowed in place of the analysis

elastic rigorous second order is the use of the approximate analysis described in 4.8.3.4.

4.8.3.4 Analysis approximate second order

4.8.3.4.1 Annex V procedures are presented to approximate elastic analysis

second order, which can be used for any larger value of the coefficient B 2,considering all floors of the structure, even when it exceeds 1.3, and that

generally provide more accurate results than those obtained by the analysis described in estimated4.8.3.3.

4.8.3.4.2 Other procedures for approximate elastic second-order analysis can be

used provided they lead to accurate results equivalent to the procedures ofAnnex V.

4.8.4 Consideration of initial imperfections of the structure as a whole

4.8.4.1 The effect of initial imperfections of the structure as a whole may be taken into accountdirectly in the analysis by considering an equivalent geometric imperfection in

form of an initial displacement between floors 200 h , Where h floor height (distance

wheelbase beams), accumulated over the height of the building. It is also admitted considerit through the simplified procedure of notional forces given in 4.8.4.2.

4.8.4.2 The effect of initial imperfections of the structure can be taken into account byapplication on each floor of the structure, a fictitious horizontal force called Forcenotional, taken equal to 0.5% of the sum of normal forces applicants calculation in allpillars and other elements resistant to vertical loads, considered on the floor. This forcenotional should be considered acting in all combinations of shares used for calculatingthe calculation of the structure. However, to avoid an overly conservative condition,allows himself not consider it in combinations that work forces due to wind, iecan consider it only for the combination of actions that act only in calculating actionsDirect permanent and result from the use and occupation of the building (see 4.7.2.1). It is not

necessary to consider them in the calculation of the horizontal support reactions.

4.8.4.3 The effect of initial imperfections is to be applied in all horizontal directionsrelevant, but only one at a time (considering both directions). The possible

torsional effects must also be considered.

4.8.4.4 Allows the analysis of the structure without directly considering the effect of imperfectionsinitials, if the requirements of 4.8.2.2.1 are met for braced structures and4.8.2.3.1 for non-braced structures.

Page 28


4.8.5 Strength and stiffness of containments

4.8.5.1 General

4.8.5.1.1 The following requirements relate to minimum resistance and stiffness that

side retainers must have in order to be effective, so that, for example, barscompressed can be calculated considering the buckling length equal to the distancebetween the points at which these contentions are present. One should strive to putperpendicular to the bar retainers; resistance (force or moment) and stiffness (force perdisplacement unit time or per unit of rotation) sloping or containmentsdiagonals should be adjusted to the angle of inclination. The evaluation of the rigidity providedthe retainers must include its dimensions and geometric properties as well as the effectslinks and anchor details.

4.8.5.1.2 Two types of containment, relative and nodal are considered. The restraint oncontrolling the motion of a point contained in contained relation to adjacent points, whileSpecifically containing the nodal point movement control contained no interaction

contained with the adjacent points (1 illustrates the two types of restraint barscompressed and flexed). The strength and stiffness provided by the stability analysis ofrestraint should not be less than the required limits.

Diagonal

Sum

NodalRelative

NodalRelative

a) Containment in compressed bars

h

N N N N

N N N N

b) Containment flexed in bars

Figure 1 - Types of containment

4.8.5.2 Floors with diagonal bracing panels or

In structures in which the lateral stability is ensured by diagonal bracing,shear walls or equivalent means, the tensile shear strength and

Page 29


stiffness necessary for stability of these systems on each floor, are given, respectively,by:

SdbrN0040P =

h

N2Sdr

br

=

Where:

r is the weighting coefficient of rigidity equal to 1.35;

NSd is the sum of the normal forces requesters calculate the pillars and other

resistant elements to vertical forces considered the floor;

h is the height from the floor, making wheelbase beams.

These stability requirements should be combined with those related to forces andSide other sources, such as wind movements.

4.8.5.3 Pillars

4.8.5.3.1 A single pillar can be contained in intermediate points along itslong and contentions relative or nodal.

4.8.5.3.2 The required strength and stiffness of the restraints on are given,respectively, by:

SdbrN0040P =

b

Sdrbr L

N2=

Where:


NSdrequestor is the normal force calculation on the pillar;

Lb is the distance from contention, observing the provisions in 4.8.5.3.4.

4.8.5.3.3 The strength and rigidity necessary nodal restraints, when these areequally spaced, are given respectively by:

N010P =

Sdbr

b

Sdrbr L

N8=

where NSd, r and Lbare defined in 4.8.5.3.2.

Page 30


4.8.5.3.4 When the distance between the points of restraint is smaller than L q, Where L q isUnlocked maximum length that allows the pillar resists normal force requestorcalculation of the buckling coefficient k = 1.00, can take L bequal to Lq.

4.8.5.4 Beams

4.8.5.4.1 The contentions of a beam shall prevent the relative displacement of the top tablesand bottom. Lateral stability of beams must be provided to prevent the restraint

lateral displacement (translational containment), torsion (twisting restraint) orcombination of the two movements. Bars subjected to bending with reverse curvature,inflection point can not be considered by itself as a restraint.

4.8.5.4.2 The contentions of translation can be relative or nodal and should be fixednear the compressed table. Additionally, the balance beams, a contention inend without support should be set close to the pulled table. Contentions translationalmust be fixed near both tables when located in the vicinity of the pointinflection in beams subjected to reverse curvature.

4.8.5.4.3 The required strength and stiffness of contention for translation are given,respectively, by:

the

dSdbr h

CM0080P =

theb

dSdrbr hL

CM4=

Where:


MSdis the bending moment calculation requestor;

htheis the distance between the centroid of the tables;

Cd is a coefficient equal to 1.00, except for containment located in the vicinity of the pointtipping in bars subjected to bending reverse camber, should be taken when

equal to 2.00;

Lb is the distance between restraints (length unlocked), observing the provisions in4.8.5.4.5.

4.8.5.4.4 The required strength and stiffness of contention nodal translation are given,respectively, by:

dSdbr

CM020P =

theh

Page 31


theb

dSdrbr hL

CM10=

where MSdC dH the, r and Lbare defined in 4.8.5.4.3.

4.8.5.4.5 When the distance between the points of restraint is smaller than L q, Where L q isunlocked maximum length which allows the beam to resist the bending moment requestercalculation, one can take G

bequal to L

q.

4.8.5.4.6 contentions torsional nodal or may be continuous along the length of the

beam. Such contentions may be fixed in any position of the cross section, notneeding to stay near the compressed table.

4.8.5.4.7 The contentions of nodal twist must have a connection with the beam capable of supporting the

bending moment, M br, And a minimum stiffness gantry or diaphragm, Tb, Whose values,

respectively, are:

bb

Sdbr LCn

LM0240M =

-

=

sec

T

TTb

1

Where:

MSd

and Lb

are defined in 4.8.5.4.3;

L is the span of the beam;

n is the number of nodal points of contention within the range;

Cb

is a modification factor defined in 5.4.2.5 and 5.4.2.6;

Tis the stiffness of the containment excluding the distortion of the beam web, given by:

2by

2Sdr

T CIEn

ML42 =

sec is the stiffness of the beam web distortion, including the effect of stiffeners

Cross the soul, if any, given by:

+=

12

bt

12

th5,1

h

E33 3ss

3wthe

thesec

r

is the weighting coefficient of rigidity equal to 1.35;

E is the modulus of elasticity of steel;

Page 32


Iy is the moment of inertia of the beam about the axis situated in the bending plane;

htheis the distance between the centroid of the tables;

twis the thickness of the beam web;

ts is the thickness of the stiffener;

bs the width of the stiffener is located on one side (using twice the width of the stiffenerfor pairs of stiffeners).

If secis less than T, Tbwill be negative, indicating that the containment torsion beam is noteffective due to inadequate rigidity to the distortion of the beam web.

When the stiffener is required, it must be extended to the total height of the barcontained and must be fixed to the table if containment torsion is also fixed to the table.

Alternatively, the stiffener is allowed to interrupt a distance equal tow

t4 of

any table of the beam that is not directly attached to the containment twist. When thespacing of the points of restraint is smaller than L q, Then L bmay be taken equal to L q.

4.8.5.4.8 For the contentions of continuous torque must be used the same expressions given

in 4.8.5.4.7, taking n L equal to 1.00 times and the rigidity per unit length,

and rigidity to the distortion of the soul, beamsec

As:

the

3w

sec h12

tE33=

4.9 Structural Integrity

4.9.1 The structural design, in addition to providing a framework capable of meeting the limit statespast and the intended period of use for the building lifespan, should allow themanufacturing, shipping, handling and assembly of the structure are performed soproper and safe working condition. It must also take into account the need tofuture maintenance, demolition, recycling and reuse of materials.

4.9.2 The basic anatomy of the structure by which actions are transmitted to the foundations must beclearly defined. Any structure characteristics that influence the stabilityGlobal must be identified and properly considered in the design. Each part of a building

between expansion joints should be treated as an isolated building.

4.9.3 The structure must be designed as a three-dimensional entity, must be robust andstable under normal load conditions and should not occur in the event that oneaccident or be used inappropriately, suffering disproportionate damage to their causes. Inabsence of specific sophisticated studies should be followed given prescriptions4.9.4 to 4.9.8.

4.9.4 Each pillar of a building shall be effectively locked by means of struts (retainers)at least two horizontal directions, preferably orthogonal at each level supported bythis pillar, including roofing, according to Figure 2.


4.9.5 Continuous lines of struts should be placed as close as possible to the edges of thefloor or roof line and each pillar, and reentrant corners anchors should beand connected to the structure according to Figure 2.

Anchors edge

Anchors edgeAnchors of the pillars

Reentrant corner

The

Beams not used as anchorsAnchors edge

Anchor for Dikethe reentrant corner

Anchor for containmentThe abutment

Figure 2 - Example of bracing the pillars of a building

4.9.6 The horizontal struts may consist of steel profiles, including those usedfor other purposes, such as floor joists and hedge shears, or the reinforcement of slabsproperly connected to the steel frame.

4.9.7 The horizontal struts and their connections must be compatible with the otherelements of the structure to which they belong and be sized for shares calculation andalso to withstand a pulling force calculation, which should not be added to otheractions, at least 2% of the requesting force calculation on the pillar or 75 kN, whichever is greater. Oncase covers without concrete slabs, the struts of the pillars and their endtheir connections shall be designed for the actions of calculation and also to supporta compressive force calculation, which should not be added to other actions, at least75 kN. In addition, the struts must meet the applicable requirements given in 4.8.5.

4.9.8 In buildings with multiple floors, pillars of the amendments should be able to withstanda force corresponding to the larger reaction of traction calculation, obtained from the combination of load

permanent and overhead applied on the pillar of a floor located between the amendment inconsideration and positioned immediately below the seam.

5 Specific conditions for the design of steel elements

5.1 Relations width / thickness on tablets elements of steel profiles

5.1.1 Classification of cross sections

5.1.1.1 Depending on the value of the slenderness of the compressed components in relation to pand r (To see5.1.1.2), respectively slenderness parameter corresponding to the lamination and parameter

slenderness corresponding to the onset of yield, the cross sections are classified into:


- Compact: sections tablets whose elements have not exceed the slendernessparameter

pand whose tables are connected continuously to the soul or souls (see 5.1.1.3);

- Semicompactas: sections that have one or more elements tablets exceeding the

parameter pBut not the parameter r (See 5.1.1.4);

- Slender: sections that have one or more elements tablets exceeding the

parameter r (See 5.1.1.5).

5.1.1.2 The slenderness of compressed elements is defined in 5.1.2 and the parameters of slenderness pand r are provided for different request types along this Standard.

5.1.1.3 Compact sections are capable of achieving a stress distribution "fullyPlastic "and have a great rotation before the occurrence of local buckling. These sectionsare suitable for cosmetic analysis, but should, for this type of analysis, having a shaftsymmetry in the plane of loading when subjected to bending, and be doubly symmetricwhen subjected to normal compression forces.

5.1.1.4 semicompactas In sections, the tablets reach the resistance elements

runoff before local buckling occurs, but not resist inelastic local bucklingthe intensity of tension required to achieve "fully plastic" distributing

strains.

5.1.1.5 In the sections slender elements tablets before flambam resistanceflow is achieved.

5.1.2 Types and slenderness of the component elements

5.1.2.1 For the purposes of local buckling, the elements of the cross sectionsusual, except the circular tubular sections are classified into AA when have twolinked longitudinal edges, and AL, when they have only one longitudinal edgebound.

5.1.2.2 The slenderness of the component elements of the cross section is defined by the relationship betweenwidth and thickness (ratio t /b).

5.1.2.3 The width (b) of some of the most common AA elements should be taken as follows:

a) for the souls of sections I, H or U-rolled, the free distance between the two tables less

rays of agreement between table and soul;

b) for the souls of sections I, H, U or welded coffin, the free distance between tables;

c) for welded sections coffin tables, the free distance between the inner faces of the souls;

d) to souls rectangular tubular sections and tables, the length of the flat part of theelement;

e) for plates, the distance between the parallel lines of fasteners or welding.

5.1.2.4 The width of some of the most common elements AL should be taken as follows:


a) sections of tables for I, H and T, half of the total width of the table;

b) to flaps and gussets U sections tables, the total width of the element;

c) for plates, the distance from the free edge to the first row of bolts or welding;

d) for the souls of sections T, the total height of the cross section, including the height of the soul and thethickness table.

5.2 prismatic bars subjected to normal traction force

5.2.1 General

5.2.1.1 This subsection applies to prismatic bars subjected to normal traction forcecaused by static actions, including bars linked by pins and lugs and round bars withThreaded ends.

5.2.1.2 In the design, the condition must be met:

RdTSdTNN

Where:

Nt, Sd

is the normal force of requesting traction calculation, determined from the

combinations of actions given in 4.7.2;

Nt, Rdis the normal force of sturdy traction calculation, determined according to 5.2.2, 5.2.6 or5.2.7, whichever is applicable.

The condition specified in 5.2.8 should still be met, relating to the maximum value ofslenderness ratio and, in the case of a bar composed, must be met given the rulesin 5.2.9.

5.2.2 sturdy Normal force calculation

The normal force resistant traction calculation, N t, RdTo be used in the design, exceptfor round bars with threaded ends and bars linked by pins, is the smallest ofvalues obtained, considering the limit states for disposal of gross section andLiquid break section according to the expressions given below:

a) for the disposal of the gross section

= yg

RdT

fTheN

b) to break the net section

= uand

RdT

fTheN

Where:

Page 36


is the weighting coefficient of resistance, equal to 1.10 for disposing of gross section

and 1.35 for net section rupture;

Theg is the gross cross-sectional area of the bar;

Theandis the effective net area of cross section, given bar as 5.2.3;

fy is the yield strength of steel;

fu is the tensile strength of steel.

5.2.3 Effective Net Area

The effective net area of a bar, The andIs given by:

ntandTheCA =

Where:

Then is the net area, as determined Bar 5.2.4;

Ct is a reduction coefficient of net area determined according to 5.2.5.

5.2.4 Net Area

5.2.4.1 In regions with holes, made for switching or for any other purpose, the areaNet, The

n, A bar is the sum of the thickness of the liquid products width of each

element, calculated as follows:

a) bolted to the width of the holes must be considered greater than 2.0 mmnominal size of these holes, defined in 6.3.5, perpendicular to the direction of the force

applied;

b) if a series of holes distributed transversely to the axis of the bar into this axis diagonal or zigzag, the net width of that part of the bar shall becalculated by deducting from the gross width the sum of the widths of all the holes in the chain, and

adding to each line connecting the two holes, the amount g4s 2 , And Mon

respectively, the longitudinal and transverse spacings (feedback) between these two

holes;

c) the net width of that critical part of the bar will be obtained by the chain holesgives the least net widths for the different possibilities of linesbreak;

d) for angles, feedback g holes in opposite flaps should be considered equal tosum of jigs, measured from the edge of the ledge, subtracted from its thickness;

e) in determining the net section area comprising welds or welds bufferFillet holes in the area of the weld metal must be discarded.

Page 37


5.2.4.2 In areas where there are no holes, the net area, A , Should be taken equal to the area

ngross cross section, The g.

5.2.5 Reduction Coefficient

5.2.5.1 The reduction coefficient of net area, C t, Bars with cross sectionsconstituted by more than one rectangular element, including rectangular tubular sections has

the following values:

a) when the traction force is transmitted directly to each of the elements ofcross section of the bar, by welds or bolts:

001Ct

=

b) when the traction force is transmitted only by only by bolts or weldsLongitudinal or by a combination of longitudinal and transversal welds tosome, but not all, elements of the cross section of the bar (should, however, beused 0.90 as the upper limit and lower limit 0.75):

c

ct

and1C

l-=

Where (Figure 3):

andc is the eccentricity of the bond, equal to the distance from the center of gravity of the bar, L,

the shear plane of the connection (in profiles with a plane of symmetry, the connectionshould be symmetrical in relation to this plane are considered and two separate bars andsymmetric, each related to a shear plane of the connection, forexample, two T sections in case I or H profiles linked the tables);

l cIn the welded joints, the length of the link is equal to the length of

welding and bolted in is the distance from first to last screw threaddrilling with larger screws, toward the normal force;

Center of gravitylower T

Center of gravityhigher T

Lower T

Higher T

G

andc

l c

l c

andc

andc

Figure 3 - Illustration of values andc

andl cin cross sections consisting of

flat elements

c) when the traction force is transmitted only by transverse welds:

Page 38


g

ct The

TheC =

Where:

Thec is the cross-sectional area of the connected elements;

Theg gross cross-sectional area of the bar.

5.2.5.2 The reduction coefficient of net area, C t, The flat plates when the traction forceis transmitted only by longitudinal welds along both its edges, has

following values:

001Ct

= To b2w

l

870Ct

= To b5,1b2w

> l

750Ct

= To bb5,1w

> l

Where:

l wis the length of the weld;

b is the plate width (distance between the welds located on both edges).

5.2.5.3 The reduction coefficient of net area, C t, Bars with tubular cross sectionsCircular has the following values:

a) when the traction force is transmitted almost uniformly throughoutthe cross section, by welds or bolts:

001Ct

=

b) when the traction force is transmitted to only a portion of the cross section,as in the situation shown in Figure 4, the procedure should be used as in b)of 5.2.5.1.

Page 39


Centre of gravitysemi-circle top

andc

andc

Centre of gravitylower semi-circle

l c

Figure 4 - Illustration of transmission of force to the tubular part of circular cross section

5.2.6 bars connected by pin and lugs

5.2.6.1 bars connected by pin

5.2.6.1.1 The normal force resistant traction calculation of a bar connected by pin excepteyebolts, is the lowest value considering the following limit states:

a) disposing of gross section tensile as 5.2.2;

b) pressure resistance of the projected contact area of the pin, as 6.6.1;

c) rupture of the net section tensile

= uf

RdT

fbt2N

d) ruptu

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Design and Execution of Steel Structures and Composite Steel-concrete Buildings