Simple Span Reinforced Concrete Slab Bridge Rating · PDF filesimple span reinforced concrete slab bridge input ... design plans 102‐103 appendix b ... simple span reinforced concrete

VDOT

Simple Span Reinforced Concrete Slab Bridge

As‐Built Model Only

September, 2011

1

Virtis V6.2

DETAILED EXAMPLE

SIMPLE SPAN REINFORCED CONCRETE SLAB BRIDGE INPUT

AS‐BUILT MODEL ONLY

Page No.

Cover Sheet 1

Table of Contents 2

Bridge Information 3‐7

Material Properties Input 8‐10

Impact and Factors 11‐13

Superstructure Definitions: Spans A and C 14‐18

Exterior Slab 19‐32

Interior Slab 33‐40

Superstructure Definitions: Span B 41‐43

Exterior Slab 44‐50

Interior Slab 51‐57

Bridge Alternative 58‐63

Rating Bridge and Review the Output 64‐74

Completing VDOT LRFR Rating Form 75‐101

Appendix A: Design Plans 102‐103

Appendix B: Dead Load Calculations 104‐105

Appendix C: LFD Live Load Distribution Factor Calculations 106‐108

Appendix D: LRFD Live Load Distribution Factor Calculations 109‐115

Appendix E: VDOT LRFR Rating Form 116‐118

Appendix F: Strength Limit State Rating Factor and Tonnage Calculations 119‐129

2

SIMPLE SPAN REINFORCED CONCRETE SLAB BRIDGE INPUT: VERSION 6.2

VERSION 6.2

American Association of State Highway and Transportation Officials

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Virti s:ll Bridge load Rating Version 6.2.0 Build date sep 22 201 0

Username virtis L-____________________ ~

Password 111111

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and Transportation Officials .Inc 444 N orth Capitol Street, N .W., Suite 249

Washington,. DC. 20001 U.S.A (202) 624-5800

'\..VDDT~,~ t 3


VERSION 6.2

CREATING A NEW BRIDGE

To create a new bridge right click on the folder where you want to save the bridge and choose New → New Bridge.

A new window will appear. Fill in the fields as appropriate under the Description tab:

Note: The description box is a good place to show the plan number used to analyze the structure. Template: Template bridges serve as templates to help develop other bridges.

Bridge Completely Defined: Check the box if the specified bridge is completely defined within the Virtis/Opis database. Do not check this box if some of the structures making up the bridge are not in the database.

BridgeWare Association Button: Opens the BridgeWare Association window allowing you to specify this current bridge as a Virtis, Opis or Virtis/Opis bridge and also to link this current bridge to a bridge in the Pontis database if Pontis is installed.

4


VERSION 6.2

Description (cont’d) tab: Fill in fields as appropriate.

No input required for the Alternatives and Global Reference Point tabs.

Traffic tab:

To find the traffic data follow the link below:

http://www.virginiadot.org/info/ct-TrafficCounts.asp

Left click the most current year.

5


VERSION 6.2

Left click Jurisdiction Publications.

Right click the excel icon for the appropriate jurisdiction.

Left click Save Target As… and save the file to a desired folder on user’s computer.

Open the excel file and the user can locate the proper traffic data for the structure.

6


VERSION 6.2

Truck PCT: The percentage of trucks in the average daily traffic.

ADT: Average Daily Traffic Directional PCT: Percentage used to compute traffic in one direction Recent ADTT: Virtis computes this value based on above inputs

For all Windows: OK button: Saves the bridge description in this window and its tabs to memory and closes the window. Apply button: Saves the bridge description in this window and its tabs to memory and keeps the window open. Cancel button: Closes the window without saving the bridge description in this window and its tabs to memory. NOTE: It is strongly recommended that the user save the bridge data at this time. In addition, the user should routinely save the bridge data during the input process.

Left click the Save icon and the Bridge Validation window will appear. Left click Continue Saving to finish the save process.

7


VERSION 6.2

SELECTING MATERIAL PROPERTIES

Expand the Materials folder.

Double click Concrete to open the Bridge Materials – Concrete Window.

Copy from Library Button: Opens the Library - Materials – Concrete window, allowing you to copy a set of concrete material properties from the library to this window.

Left click the appropriate concrete properties and left click the OK Button to accept.

8


VERSION 6.2

Left click OK to accept and close.

Repeat the process for Reinforcing Steel. Double click Reinforcing Steel to open the Bridge Materials – Reinforcing Steel Window.

Copy from Library Button: Opens the Library - Materials – Reinforcing Steel window, allowing you to copy a set of steel reinforcing steel material properties from the library to this window.

9


VERSION 6.2

Left click the appropriate reinforcing steel properties and left click the OK Button to accept.

Type: User can select whether the reinforcing steel is Plain, Epoxy, Galvanized, or Other. For this example select Plain. Left click OK to accept and close.

10


VERSION 6.2

SELECTING IMPACT/DYNAMIC LOAD ALLOWANCES

Double click Impact / Dynamic Load Allowance to open.

15.0% and 33.0% are AASHTO LRFD defaults. Left click the OK button to accept and close.

11


VERSION 6.2

SELECTING FACTORS

Expand the Factors folder.

Double click LRFR to open.

Left click the Copy from Library… button to open the library data for LRFR factors.

Select the appropriate factors and left click the OK button to accept.

12


VERSION 6.2

Left click the OK button to accept and close.

r A Foctors - l RfR -JLLl

NMJe: j2003AASHTO LRFR Spedic4tions I Description: I ~AASHTO LRFR Spedications, IlcIuOOo 2Ol5

I'· ...... ~ Faclo:r):~~l~ Peo"'losdt Conc,eje ,,,_ Wood

B,.Tl'P'" ISteei !vi Oft· ~ load Vehiele

li"nl State ".~ "'" nvenl OJ)efa l , '"'" Cansille<

" OW " U. U. U. ." O. , ., '"'" '''''''' 1.250 '''' 1.750 1.350 T ... 0 - -SlRfNGT 1.250 '''' 11300

To .. 0 -SERVCE I 1.000 '.000 '.000 """ '000 - - - -FAll3IJE ' .000 ' .000 0,750 0 -LD

I Cow hom Libo"J>_ II OK II - II C .... I

'\..VDDT~,~ t 13


VERSION 6.2

CREATING SUPERSTRUCTURE DEFINITIONS: SPAN A&C

Double click SUPERSTRUCTURE DEFINITIONS to open.

Select Girder Line Superstructure and left click the OK button to accept and close.

The Girder Line definition will be used since a 12” wide portion of the slab will be rated.

Fill out the following fields:

Name: Since spans A and C are identical, the name is AS-BUILT Span A&C.

Description: No information required, but user can input additional information or assumptions if desired.

Live Load Lanes: In most cases, Multi-Lane should be selected.

Member Alt. Types: Select R/C since a reinforced concrete slab is rated.

14


VERSION 6.2

Left click the Analysis tab.

Consider structural slab thickness for rating: Check this box if the structural slab thickness should be used to compute section properties for rating. If this box is not checked, the rating will use section properties computed from the total deck thickness.

Factor Override: None selected. Factor Override allows you to override the System Defaults library factors with a set of factors that have been entered for this bridge only. Factor overrides will remain when files are imported into future versions of Virtis. Unless factors specific to the bridge are required, overrides are not recommended as they can prevent updates to System Defaults in future versions (e.g., legal load SHV factors in the MBE).

No input required for the Engine tab.


15


VERSION 6.2

DEFINING LOAD CASES

Double click Load Case Description to open the Load Case Description window.

Left click Add Default Load Case Descriptions to apply default load cases. The default load cases include dead load (DC1) acting on non-composite section, dead load (DC2) acting on long term composite section, dead load (DW) acting on long term composite section and stay-in-place forms acting on non-composite section. These default load cases can be edited and modified as desired.

16


VERSION 6.2

Left click the OK button to accept and close.

A load Case DeKription .J.c:!

°l~' '+'7 ,

"f'<estrel.ed rneni>erl ~ AddDe/~~1 c...e Del"'" . • I "~ II D~e I I 0 ... I

II OK II - II c..... I

'\..VDDT~,~ t 17


VERSION 6.2

DEFINE STEEL REINFORCEMENT

Double click Bar Mark Definitions.

Fill out the fields as appropriate based on the information in the plans (See Appendix A for the design plans).

Bar Type: Select the Straight bar type even if the bar has hooks at the end. The user will be able to define the bar as fully developed later to model hooks at the start and end of the bar.

A Dimension: Use the CL-to-CL of bearing dimension for the bridge.


18


VERSION 6.2

CREATING A MEMBER: SPAN A&C – EXTERIOR SLAB

Double click MEMBERS to open the Member window.

~ Bridge Workspace - 02975

8 A 02975 8 Cl Materials

Cl Strucbl~ Steel Cl Concrete

I ClassA~) 8 Cl Rei1forcilg Steel

• Qade60 D Prestress Stro!llld (]Tmb«

Cl Beam Shapes (il I2J Appu"ter.1Inces

::\ lrT'Ipa<:t I DynMiC Load AIowance

8 Cl Factors Cl LFD I2J LRFD

8 Cl LRFR LRFR 2003 AASHTO LRFR Spedfications

8 Cl SLPERSTRUCTURf DEFINm ctlS 8 ~ AS-8UILT Span A&C

::l In,JaCt I Dynamic Load AIowance ;;tt Load Case Desa1>tion .JJr ~strucble Loads

III CJ Shear Rei1forcement Definitions 8 CJ B« Mark Definitions

.:.....=. SC1104

(] i'EMiERS] o BRIDGE AL TERNA TlVES

'\..VDDT~,~ t 19


VERSION 6.2

Fill out the fields as appropriate based on the information in the plans.

Member Name: Since this is the input for the the exterior portion of the slab use “Exterior Slab” for the name.

Description: No information required, but user can input additional information or assumptions if desired.

Number of Spans: Since this is a simple span enter 1 as the number of spans.

Deck Concrete Crack Control Parameter (Z): Enter 130.00 kip/in since the top of the slab is directly exposed to environmental elements.

Member Location: Select Exterior

Deck Exposure Factor: Use 1.000 for a Class 1 exposure condition.


20


VERSION 6.2

APPLYING DEAD LOADS

Double click Member Loads to apply loads to the members.

Typically the two uniform loads applied to a slab are a DC2 load for the barrier and DW load for the wearing surface. However, since the example bridge does not have a wearing surface, only a DC2 load is required.

Left click the dropdown menu and left click DC2.

21


VERSION 6.2

Left click the New button and enter the appropriate uniform load of the barrier that is distributed to a 12” portion of the slab. See Appendix B for a sample calculation.


22


VERSION 6.2

CREATING A MEMBER ALTERNATIVE: SPAN A&C - EXTERIOR SLAB

Double click MEMBER ALTERNATIVES to further define the member.

Select Reinforced Concrete from the left drop down menu.

Select Reinforced Concrete Slab from the right drop down menu.

Left Click OK to accept.

23


VERSION 6.2

Description tab:

Member Alternative: Exterior Slab

Sustained Modular Ratio Factor: 2.00 for concrete members.

Crack control parameter (Z): 170.00 kip/in since the bottom of the slab is not directly exposed to the environment.

Exposure Factor: 1.000 for a Class 1 exposure condition.

Default Rating Method: LRFR

Analysis Module:

LFD: Virtis LFD

LRFR: Virtis LRFR

Leave the ASD and LRFD modules as the default values.

No changes to the following tabs:

Factors

Engine

Import

24


VERSION 6.2

Control Options tab:

Select the options shown in the screen shot to the left.


25


VERSION 6.2

DEFINING LIVE LOAD DISTRIBUTION FACTORS

Expand Exterior Slab (E) (C).

Double click Live Load Distribution.

Standard tab:

Distribution Factor Input Method: Use Simplified Method.

Input the LFD live load distribution factor for moment. See Appendix C for a sample calculation.

26


VERSION 6.2

LRFD tab:

Virtis does not compute the LRFD live load distribution factors correctly.

Therefore, under the LRFD tab left click the New button.

Input the LRFD live load distribution for Deflection.

See Appendix D for a sample calculation.

27


VERSION 6.2

Select Moment from the Action drop down menu and repeat the process to input the LRFD live load distribution factors for moment.

Input the LRFD live load distribution for Moment.

Input the LRFD live load distribution for Shear and left click OK to accept and close.

28


VERSION 6.2

DEFINING THE GIRDER PROFILE

Double click Girder Profile.

Under the Section tab input the appropriate information:

Beam Dimension: 12.00 in since a 12 inch wide portion of the slab is analyzed.

Concrete Material: Select Class A (US) from the drop down menu.

Modular Ratio: 8.0 (See calculation below)

Sacrificial Wearing Surface: 0.50 in.

29


VERSION 6.2

Web tab:

Begin Depth: Top of slab to bottom of slab.

Depth Vary: None

Support Number: 1

Start Distance: 0.00 ft

Length: 39.25 ft (CL BRG to CL BRG)

30


VERSION 6.2

Under the Reinforcement tab: Left click the New button.

31


VERSION 6.2

Reinforcement tab:

Input the fields based on the information in the plans.

Bar Mark: SC1104

Invert: Unchecked since the bar mark is defined as straight

Measured From: Bottom of Slab

Distance: 2.75 in (from bottom of the slab to the CL of reinforcement)

Number: 3.0 bars ( 12” wide slab / 4” rebar spacing )

Bar Spacing: 4.00 in

Side Cover: 3.00 in

Support Number: 1

Direction: Right (defines if the start distance for the rebar is to the right or left of the support number.

Start Distance: 0.00

Full Developed: Checked since there are hooks at the end of the bar


***THE INPUT FOR THE EXTERIOR SLAB IS COMPLETE. USER CAN ADVANCE TO THE INTERIOR SLAB.

32


VERSION 6.2

CREATING A MEMBER: SPAN A&C - INTERIOR SLAB

Right click Exterior Slab directly underneath the MEMBERS folder and select Copy.

Right click MEMBERS and select Paste.

33


VERSION 6.2

Double click Copy of Exterior Slab.

Change the Member Name to Interior Slab.

Change the Member Location to Interior.


34


VERSION 6.2

APPLYING DEAD LOADS

Since the dead loads applied to the exterior slab are equal to the loads applied to the interior slab the user is not required to open the Girder Member Loads window.

35


VERSION 6.2

CREATING A MEMBER ALTERNATIVE: SPAN A&C - INTERIOR SLAB

Expand the MEMBER ALTERNATIVES folder.

Double click Exterior Slab (E) (C) to open the Member Alternative Description window.

Description Tab:

Change the Member Alternative name to Interior Slab.

The user is not required to update any other fields.


36


VERSION 6.2


Expand Interior Slab (E) (C).


Standard tab:

This input is the same for the exterior and interior slabs. Therefore, updates by the user are not required for this tab.

37


VERSION 6.2

LRFD tab:

Update the 1 lane and Multi-Lane values for the interior slab (See Appendix D) for Deflection.

Update the 1 Lane and Multi-Lane values for the interior slab (See Appendix D) for Moment.

Update the 1 Lane and Multi-Lane values for the interior slab (See Appendix D) for Shear.

Left Click OK to accept and close.

38


VERSION 6.2



The information for the Section and Web tabs do not have to be revised.

Proceed to the Reinforcement tab.

39


VERSION 6.2

Under the Reinforcement tab, revise the following input:

Number: 2.0 bars ( 12” wide slab / 6” rebar spacing )

Bar Spacing: 6.00 in


***THE INPUT FOR THE INTERIOR SLAB IS COMPLETE. USER CAN ADVANCE TO THE INPUT FOR SPAN B.

40


VERSION 6.2

CREATING SUPERSTRUCTURE DEFINITIONS: SPAN B

Right click the SUPERSTRUCTURE DEFINITION, AS-BUILT Span A&C.

Left click Copy.

Right click the SUPERSTRUCTURE DEFINITIONS folder.

Left click Paste.

41


VERSION 6.2

Copy of AS-BUILT Span A&C will appear as a new SUPERSTRUCTURE DEFINITION.

Double click Copy of AS-BUILT Span A&C.

Change the name to AS-BUILT Span B.

User is not required to change any other input for this window.


42


VERSION 6.2

DEFINE STEEL REINFORCEMENT

Expand the Bar Mark Definitions folder.

Double click SC1104 to open the Bar Mark Definition window.

Change the name to SC1105.

Change the “A” Dimension to 39.00 ft.


43


VERSION 6.2

CREATING A MEMBER: SPAN B – EXTERIOR SLAB

Expand the MEMBERS folder and double click Exterior Slab.

Change the span length to 39.00 ft.


44


VERSION 6.2

APPLYING DEAD LOADS

Since the dead loads applied to Span A&C are equal to the loads applied to Span B the user is not required to open the Girder Member Loads window.

45


VERSION 6.2

CREATING A MEMBER ALTERNATIVE: SPAN B – EXTERIOR SLAB


Double click Exterior Slab (E) (C).

Updates are not required for the Member Alternative Description window.


46


VERSION 6.2


Expand Exterior Slab (E) (C).


Standard tab:

Update the distribution factor for Moment (See Appendix C).

47


VERSION 6.2

LRFD tab:

Update the length to 39.00 ft.

Update the 1 lane and Multi-Lane values for the exterior slab (See Appendix D) for Deflection. In this instance the values are equal to Span A&C’s values.


Update the 1 Lane and Multi-Lane values for the exterior slab (See Appendix D) for Moment. In this instance the values are equal to Span A&C’s values.


Update the 1 Lane and Multi-Lane values for the exterior slab (See Appendix D) for Shear. In this instance the values are equal to Span A&C’s values.


48


VERSION 6.2



The information for the Section tab does not have to be revised.

Proceed to the Web tab.

49


VERSION 6.2

Web Tab:

Update the Length to 39.00ft.

Updates are not required for the Reinforcement tab.


***THE INPUT FOR THE EXTERIOR SLAB IS COMPLETE. USER CAN ADVANCE TO THE INTERIOR SLAB.

50


VERSION 6.2

CREATING A MEMBER: SPAN B – INTERIOR SLAB

Double click Interior Slab.

Change the span length to 39.00 ft.


51


VERSION 6.2

APPLYING DEAD LOADS

Since the dead loads applied to Span A&C are equal to the loads applied to Span B the user is not required to open the Girder Member Loads window.

52


VERSION 6.2

CREATING A MEMBER ALTERNATIVE: SPAN B – INTERIOR SLAB


Double click Interior Slab (E) (C).

Updates are not required for the Member Alternative Description window.


53


VERSION 6.2


Expand Interior Slab (E) (C).


Standard tab:

Update the distribution factor for Moment (See Appendix C).

54


VERSION 6.2

LRFD tab:


Update the 1 lane and Multi-Lane values for the interior slab (See Appendix D) for Deflection.


Update the 1 Lane and Multi-Lane values for the interior slab (See Appendix D) for Moment.


Update the 1 Lane and Multi-Lane values for the interior slab (See Appendix D) for Shear.


55


VERSION 6.2



The information for the Section tab does not have to be revised.

Proceed to the Web tab.

56


VERSION 6.2

Web Tab:

Update the Length to 39.00ft.

Updates are not required for the Reinforcement tab.


***THE INPUT FOR THE INTERIOR SLAB AND SPAN B IS COMPLETE. THE USER CAN ADVANCE TO CREATING BRIDGE ALTERNATIVES.

57


VERSION 6.2

CREATING A BRIDGE ALTERNATIVE

A bridge can have several unique bridge alternatives. Each bridge alternative must include the entire bridge but can consist of a different layout of superstructures. The number of spans, the span lengths, and the pier locations are defined within the bridge alternative (and its accompanying windows). Entering different bridge alternatives can be useful when comparing various alternatives for a preliminary study. BRIDGE ALTERNATIVES permits the user to determine which spans to include in an analysis. For example, the user can decide to include only AS-BUILT Span A&C in the analysis and exclude AS-BUILT Span B. The rating summary will then only have results from Span A&C rather than comparing Span A&C to Span B. Typically however, every span inputted will be included in a BRIDGE ALTERNATIVE.

Double click BRIDGE ALTERNATIVES.

58


VERSION 6.2

Alternative Name: AS-BUILT


Double click SUPERSTRUCTURES.

59


VERSION 6.2

Superstructure Name: AS-BUILT Span A&C

No action is required for the tabs.


Expand AS-BUILT A&C.

Double click SUPERSTRUCTURE ALTERNATIVES.

60


VERSION 6.2

Alternative Name: AS-BUILT Span A&C

Superstructure Definition: Select AS-BUILT Span A&C from the drop down menu.


***THE INPUT FOR THE SPAN A&C BRIDGE ALTERNATIVE IS COMPLETE. USER CAN PROCEED TO THE SPAN B BRIDGE ALTERNATIVE.

61


VERSION 6.2

Double click SUPERSTRUCTURES.

Superstructure Name: AS-BUILT Span B

No action is required for the tabs.


62


VERSION 6.2

Expand AS-BUILT B.

Double click SUPERSTRUCTURE ALTERNATIVES.

Alternative Name: AS-BUILT Span B

Superstructure Definition: Select AS-BUILT Span B from the drop down menu.


***THE INPUT FOR SPAN B AND THE ENTIRE BRIDGE IS NOW COMPLETE. MAKE SURE THE FILE IS SAVED PRIOR TO ANALYSIS.

63


VERSION 6.2

ANALYSIS

The file is now ready to be analyzed. The user can either analyze individual beams with the file open or analyze the entire bridge with the file closed.

To analyze an individual member, highlight the MEMBER ALTERNATIVE of interest and left click the View Analysis Settings Icon.

The Analysis Settings window will appear. On the Rating Method dropdown menu, change the method to LRFR.

64


VERSION 6.2

Add the vehicles shown in the screen shot to the Vehicle Summary list.

This is done by first left clicking the destination such as Design Load Rating, Legal Load Rating, and Permit Load Rating in the right column. Then, left click the desired vehicle from the left column and left click the Add to Rating >> Button.

Once all vehicles for the LRFR Simple Span template have been entered, left click the Advanced button above the right column.

65


VERSION 6.2

For the two Blanket Permit vehicles, change the Frequency to Unlimited Crossings.


Once complete, this can be saved as a Template for future ratings. Left click the Save Template button.

Type LRFR Virtis Engine SS < 200 Ft for the Template Name and Left Click the Save button.

Left click OK on the Analysis Settings window to accept and close.

66


VERSION 6.2

ANALYZE MEMBER

To analyze a specific member, right click the desired MEMBER ALTERNATIVE and select Analyze.

Allow the program to analyze the member alternative. After the analysis is completed, the user can read any warnings or errors by scrolling up the Analysis Progress window.

Click OK to proceed to view results.

67


VERSION 6.2

To view the results keep the analyzed MEMBER ALTERNATIVE selected.

Left click the View Analysis Report icon.

The Analysis Results window will appear. To view a more compact version of the results, select Single rating level per row under the Display Format Window.

68


VERSION 6.2

Exterior Slab Rating Results:

.,. UlfR Opera .00 m 19.63 _ (50.0) STllENG-rn~ eM"""" f~"", .... ReGueste<J A.s ReGuested

-,~ UlfR ' WeIl! 122.07 3.391 23.55 _ (M.O) STllENG-rn~ eM"""" f~"", .... ReGueste<l A.s ReGuested

-,~ UlfR Opera 153.1' ' .396 23.55 _ (M.O) STllENG-rn~ eM"""" f~"", .... ReGueste<l A.s ReGuested

hnOem UlfR ' weIlI 82.16 l.41J 19.63 _ (50.0) STllENG-rn~ eM"""" f~"", .... ReGueste<l A.s ReGuested

hnOem UlfR Opera 106.51 ... 13 19 .63 _ (50.0) STllENG-rn~ eM"""" f~"", .... ReGueste<l A.s ReGuested

True<· Lane UlfR ' weIlI 100." l.,W 19.63 _ (50.0) STllENG-rn~ eM"""" f~"", .... ReGueste<l A.s ReGuested

True<· Lane UlfR Opera 1:llI.1T 3.6 16 19 .63 _ (50.0) STllENG-rn~ eM"""" f~"", .... ReGueste<l A.s ReGuested

Tandem· Lane UlfR ' WeIlI 6T.ll3 2.715 19 .63 _ (50.0) STllENG-rn~ eM"""" f~"", .... ReGueste<l A.s ReGuested

Tandem· Lane UlfR Opera MOO 3.520 19 .63 _ (50.0) STllENG-rn~ eM"""" f~"", .... ReGueste<l A.s ReGuested

-,~ ~" L~.I 13.8.97 HT4 19.63 _ (50.0) STllENG-rn~ eM"""" f~"", .... ReGueste<l A.s ReGuested

-,~ ~" L~.I 113.46 ' .5n 19.63 _ (50.0) STllENG-rn~ eM"""" f~"", .... ReGueste<J A.s ReGueste<J

-,~ ~" L~.I 13.4.12 ' .l2T 19.63 _ (50.0) STllENG~~ eM"""" f~"", .... ReGueste<J A.s ReGueste<J

-,~ ~" L~.I 135. ' 3 1.E9T 19.63 _ (50.0) STllENG~~ eM"""" f~"", .... ReGueste<J A.s ReGueste<J

-,~ ~" L~.I 141.71 1.65T 19.63 _ (50.0) STllENG~~ eM"""" f~"", .... ReGueste<J A.s ReGueste<J

-,~ ~" L~.I 202.60 ,~ 19.63 _ (50.0) STllENG~~ eM"""" f~"", .... ReGueste<J A.s ReGueste<J

-,~ ~" '-' ., 5.!U5 21.55 _ (60.0) STllENG~~ eM"""" f~"", .... ReGueste<J A.s ReGueste<J

-,~ UlfR Permt =./. 1.8T' 19 .63 _ (50.0) STllEIIG~-<I eM"""" f~"", .... ReGueste<J A.s ReGueste<J

-,~ UlfR Permt IT6.!12 1.932 19 .63 _ (50.0) STllEIIG~-<I eM"""" f~"", .... ReGueste<J A.s ReGueste<J

V' lis LAFA EnoJi>e Ve<srn 6.2.0. :nJl

~.

69


VERSION 6.2

ANALYZE FILE FROM BRIDGE EXPLORER

To analyze the entire file at once, first Save and then Close the bridge.

In the Bridge Explorer window, select the bridge, right click, and select Rate.

70


VERSION 6.2

The Analysis Settings window will appear.

If a template has already been created, left click the Open Template button.

Left click LRFR Virtis Engine SS < 200 Ft and left click the Open button.

71


VERSION 6.2

Left click OK to accept the template and rate.

r~ Anlll~; 5 Settings ~ I.:.J\..n

Ratil9 Method l LAFR Iv! ~$IITwe o S~ve ~s ReslA,

Vel"icles D_ E_ DesaPtion

T ,4/foc Di-ection ( Rehem I [ T~arYVefj:Ie$ II Advlf"lCed .. _ I I Both li'ections Iv! Vehicle Selection: Vehicle S\.Im1ary.

H 15-44

~ -" (3 Ratr.gVehicIes H 20-44 R ..... (3 LRFR HL·93 (SI) GJ 9 Desigl LlW1 R~ HL·93 (US) (3 Inventor;o HS 15-44 HL·93 (US) HS 20 (SI )

R_. HS·2O·Lene L~ Oliy

HS 20-44 HS·2O-TMdem lMle-T we Leoal LlW1

,,~ HS-2O-Tn.1CI<. DtW

LAFD Fatiop, Truck (S I) "'""', (3 Operatng LAFO Fatiop, Truck (US) GJ HL-93 (US) r ... 3 HS-2O-Lene L~ Only Type 3·3 HS·2O·TMdem Type 352 HS·2O·Tn.ICI<.OIiy

8 .,.., Fatigue B~et Permit 115 (Bp·1 15) Le~ LO»:l Rating B~eI Permit 30 (BP·9IJ) NoIionoI R..ting lmoj-NRL BP-115 (Coni. SPaIlS C( > 2IlJ It ./ SU' Bp·30 (Cen. Spans C( >2COi) SUS HL·93· Negative Moments (30' SUS HS·20-Lene Load Only SU7 HS-20-hndem VA Twe 3 HS·20-T".ICI<.O Iiy VA Twe 352 Lene Leoal L<l<'ld-Nel)..tive Mom 8 Permit Load R8I~ LAFD Fatiop, T,uck IC( Rat~ B~et Permit 115 [BP-115j N ot~ Rati:1g Lo.»NRL B~et Permit 30 (BP·30) su. SUS 5U6 5U7 VA TypeJ VA Type3S2

e User Defned Pd-UpTn.d( P

<J, ~.:J ( Reset ( ( CIo, ( I Open Template II S~veT~e I I OK I - ( C~. (

'\..VDDT~,~ t 72


VERSION 6.2

Allow the bridge to run. Once the analysis is completed, the user can read any warnings or errors by scrolling up on the Analysis Progress window.

Left click OK to view results.

The Bridge Rating Results window will appear. To view a more compact set of results, select Single rating level per row.

73


VERSION 6.2

FINAL STRUCTURE RATINGS

Note: The rating of the structure is now complete. Continue to the next sheet to fill out the rating form.

74


VERSION 6.2

COMPLETING VDOT LRFR RATING FORM

Complete the information fields at the top portion of rating form. Structure identification information can be obtained from the current inspection report for the bridge.

The VDOT Reviewer line should be left blank.

The box in the upper right hand corner of the rating form is for the seal and signature of a professional engineer licensed in the state of Virginia.

75


VERSION 6.2

DESIGN LOAD: HL-93

To fill out the rating information for the HL-93 vehicle, first highlight the HL-93 (US) Inventory and Operating Rating Level rows in the Bridge Rating Results window.

Then, left click the View Structure Rating Results window.

The Structure Rating Results window will appear. Since AS-BUILT Span A&C has lower ratings than AS-BUILT Span B, highlight both the Inventory and Operating Rating Level rows for AS-BUILT Span A&C.

Gross Vehicle Weight

76


VERSION 6.2

Left click the View Member Rating Results button.

The Member Rating Results window will appear.

Since the interior slab has lower ratings than the exterior slab, the rating information for the interior slab will be recorded on the rating form. The HL-93 vehicle is the only vehicle without a tonnage since it is a truck load combined with a lane load. The CONTROLLING FORCE column will be filled in later.

Note: For all results do not round up. Only record 2 significant digits for the rating factor.

77


VERSION 6.2

DESIGN LOAD: HS-20

To fill out the rating information for the HS-20 vehicle, first highlight the HS-20 Truck Only Inventory and Operating Rating Level rows in the Bridge Rating Results window. The HS-20 Lane Load Only and HS-20 Tandem ratings are for informational purposes only and are not included on the rating form.


78


VERSION 6.2

The Structure Rating Results window will appear. Since AS-BUILT Span A&C has lower ratings than AS-BUILT Span B, highlight both the Inventory and Operating Rating Level rows for AS-BUILT Span A&C.



Since the interior slab has lower ratings than the exterior slab, the rating information for the interior slab will be recorded on the rating form. The CONTROLLING FORCE column will be filled in later.

Note: For all tonnages do not round up. Instead, round down to the nearest ton.

79


VERSION 6.2

LEGAL LOAD: VA TYPE 3

To fill out the rating information for the VA-Type 3 vehicle, first highlight the VA Type 3 row in the Bridge Rating Results window.


The Structure Rating Results window will appear. Since AS-BUILT Span A&C has lower ratings than AS-BUILT Span B, highlight the row for AS-BUILT Span A&C.


80


VERSION 6.2



81


VERSION 6.2

LEGAL LOAD: VA TYPE 3S2

To fill out the rating information for the VA-Type 3S2 vehicle, first highlight the VA Type 3S2 row in the Bridge Rating Results window.




82


VERSION 6.2



Note: The Lane legal load is not rated for simple span bridges. Add dashes to this row for clarity.

83


VERSION 6.2

PERMIT LOAD: BP-90

To fill out the rating information for the BP-90 vehicle, first highlight the Blanket Permit 90 (BP-90) row in the Bridge Rating Results window.




84


VERSION 6.2



85


VERSION 6.2

PERMIT LOAD: BP-115

To fill out the rating information for the BP-90 vehicle, first highlight the Blanket Permit 115 (BP-115) row in the Bridge Rating Results window.




86


VERSION 6.2



87


VERSION 6.2

SH VEHICLE: NRL

To fill out the rating information for the NRL vehicle, first highlight the Notional Rating Load-NRL row in the Bridge Rating Results window.


88


VERSION 6.2





89


VERSION 6.2

SH VEHICLE: SU4

To fill out the rating information for the SU4 vehicle, first highlight the SU4 row in the Bridge Rating Results window.


90


VERSION 6.2





91


VERSION 6.2

SH VEHICLE: SU5



92


VERSION 6.2





93


VERSION 6.2

SH VEHICLE: SU6



94


VERSION 6.2





95


VERSION 6.2

SH VEHICLE: SU7

To fill out the rating information for the SU7vehicle, first highlight the SU7 row in the Bridge Rating Results window.


96


VERSION 6.2





97


VERSION 6.2

COMPLETING THE VDOT RATING FORM: CONTROLLING FORCE

Once the controlling member(s) is known, the user can obtain the controlling force for each vehicle by double clicking the bridge in the Bridge Explorer window to open the file.

Expand the folders to get to the controlling MEMBER ALTERNATIVE. For the example, this is the Interior Slab for AS-BUILT Span A&C.

Select the appropriate rating template and right click Interior Slab (E) (C) and select Analyze.

98


VERSION 6.2

Left click OK on the Analysis Progress window when the analysis is complete.

Highlight Interior Slab (E) (C) and left click the View Analysis Report icon.

99


VERSION 6.2

The Analysis Results – Interior Slab window will appear

Select Single rating level per row from the Display Format drop down menu.

The controlling force can be obtained from the Limit State column. Fill in the rating form as appropriate. See Appendix E for the completed rating form.

100


VERSION 6.2

COMPLETING THE RATING FORM: ASSUMPTIONS/COMMENTS

The second page of the rating form provides space for assumption and comments. Some common assumptions and comments are for material strengths, which plan was used, wearing surface thicknesses, and any deterioration or other changes applied to the structure.

If the current inspection report indicates that there is deterioration, the user will have to create an IR (inspection report) structure in addition to the AS-BUILT within Virtis. For simple span reinforced concrete slabs, the typical deterioration that warrants an IR structure is section loss to the longitudinal reinforcement.

***THE BRIDGE RATING IS NOW COMPLETE.

101

APPENDIX A: DESIGN PLANS

102

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PART TRANSVERSE SECTION LONGITUDINAL SECTION

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DETAIL A -JL.:~

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• ThIs do .. 1><1 ' Ine l,,~ , ST S"i .. ,no wn In Sid. Secllon, Th .. e bo tl 0 .. lobuloted In In" RoodW{J1 Soclion.

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CONSTRUCTION JOINT

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NOTCS ;

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Si"'1j~ "'''''9'' c",uf,..""lio", ""il" "on -po /;""'hq 699""96r-:, .,i/f b~ r~ui"'." Fo,.. ""<! 0;-,-.1'1': d,.cK. No tw" .>1"9': con.-I..-".I,""" ... '" b" ,,110"'<14'.

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PART PLAN OF DECK DRAINS ok"I,. , ~-.J"-O-

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PART PLAN

COMMONWEALTH or VIFIGIN'~ DUItoIUMENT 0' TRAI' SPOI!T.lT1ON

.. ... g;!,!:" .. \%p '*"" " 'r ttCliol

SL AB SPANS SPANS A,Bae ... <lul'l, 198 265-47 -'. ~ ., 7

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LONGITUDINAL SECTION

., NOlo.:

O;"".";on. ","0". In bending diag,am 0, . 0"1-'~'OUI 01 ba, s.

I ThI . do .. no l ! ncl~~e ST S .. i .. _nO ,;" I. Side Secl lon. Th .. e ball oro labulalOd I. !ho lloodwa, S.cti~n.

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Nor" , Join . Seal .. 10 .... nd 00.0 .. • ,,11 ,.,HlM ", .. _ . "" s_'.r,, ~ pJlr"pll S;I S;~t."" c-~.on .. ~~" _ .•.

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T"" "'''''''''<let ,,,,," bid priDO "" '-:Mcr~'~ <:1. ,If " f~ ,"elud" til" " ... 1 0' d .. ~l' Pno.,. .. . """"" iII.'''''I~ <III _' .. r~/~ , I_I .. , ~" ':D"'""'. Mb_. ";"nd~"t"/~ ''''.''''''f ,., "" ... pt..fl fI><...-A.

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PART PLAN OF DECK DRAINS .k",,, , ~.,I'- ()"

PART PLAN

. " a,"~ In Fie ld

COMMONWEAlTH OF VIRGINI~ DU\oIIIMENT 0' TRAlISPOIITATlOI<

SLAB SPANS

SPANS A,B8C

"- Dow., ... ... ~=-.. "\fop ... ..~

_ .. .. - CMe)'" " ttCl'd tlul,/, I'M 265-47 :! .r ,

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103

APPENDIX B: DEAD LOAD CALCULATIONS

104

Uniform DC2 Load for Parapet

gconc = 150 pcf

H1 3.00 in

H2 10.00 in

H3 19.00 in

H 32.00 in

W1 7.00 in

W2 2.00 in

W3 6.00 in

W4 5.00 in

W 20.00 in

Weights1 = ( 7 in + 2 in + 6 in ) * 3 in / 144 * 150 pcf = 46.9 lb/ft2 = 0.5 * 7 in * 10 in / 144 * 150 pcf = 36.5 lb/ft3 = 2 in * 10 in / 144 * 150 pcf = 20.8 lb/ft4 = 0.5 * 2 in * 19 in / 144 * 150 pcf = 19.8 lb/ft5 = 6 in * ( 10 in + 19 in ) / 144 * 150 pcf = 181.3 lb/ft6 = 0.5 * 5 in * 32 in / 144 * 150 pcf = 83.3 lb/ft

Total = 388.5 lb/ft

Railing Weight = 0.0 lb/ft

Total Wt. with Railing = 0.389 kip/ftg p/

1/2 Bridge Width = 15.00 ft

Width of slab analyzed, W = 1.00 ft

Parapet Load for a 1.00 ft strip = 0.389 / 15 = 0.026 kip/ft

VERSION 6.2105

APPENDIX C: LFD LIVE LOAD DISTRIBUTION FACTOR CALCULATIONS

106

LFD Live Load Distribution Factor Calculation: Span A&C

Distribution Width (Use shortest span conservative assumption)

‐ AASHTO Standard Specifications for Highway Bridges, 16th Ed, 3.24.3.2 states:

"For wheel loads, the distribution width, E, shall be (4 +0.06S) but shall not exceed 7.0 feet."

VERSION 6.2

Distribution Width (Use shortest span, conservative assumption)

Span Length, S = 39.25 feet

Distribution Width, E = 4 + 0.06*S = 6.36 feet

Is E < 7 feet? YES therefore Span length OK

Width of slab analyzed, W = 1.00 feet

Distribution Factor for Moment

Distribution Factor, DFM = W / E = 0.157

Distribution Factor for Shear

‐ AASHTO Standard Specifications for Highway Bridges, 16th Ed, 3.24.4 states:

"Slabs designed for bending moment in accordance with Article 3.24.3 shall be considered satisfactory in bond and shear.""Slabs designed for bending moment in accordance with Article 3.24.3 shall be considered satisfactory in bond and shear."

Therefore, distribution factors for shear will be ignored.

VERSION 6.2107

LFD Live Load Distribution Factor Calculation: Span B

Distribution Width (Use shortest span conservative assumption)

‐ AASHTO Standard Specifications for Highway Bridges, 16th Ed, 3.24.3.2 states:

"For wheel loads, the distribution width, E, shall be (4 +0.06S) but shall not exceed 7.0 feet."

VERSION 6.2

Distribution Width (Use shortest span, conservative assumption)

Span Length, S = 39.00 feet

Distribution Width, E = 4 + 0.06*S = 6.34 feet

Is E < 7 feet? YES therefore Span length OK

Width of slab analyzed, W = 1.00 feet

Distribution Factor for Moment

Distribution Factor, DFM = W / E = 0.158

Distribution Factor for Shear

‐ AASHTO Standard Specifications for Highway Bridges, 16th Ed, 3.24.4 states:

"Slabs designed for bending moment in accordance with Article 3.24.3 shall be considered satisfactory in bond and shear.""Slabs designed for bending moment in accordance with Article 3.24.3 shall be considered satisfactory in bond and shear."

Therefore, distribution factors for shear will be ignored.

VERSION 6.2108

APPENDIX D: LRFD LIVE LOAD DISTRIBUTION FACTOR CALCULATIONS

109

LRFD Live Load Distribution Factor Calculation for Span A&C

Note: All References taken from AASHTO LRFD Bridge Design Specifications, 4th ed (2007 with 2008 Interims)

INPUT

Physical Span Length, L = 39.25 ft

Width of Slab Analyzed, WA = 12.00 in

Physical Edge‐to‐Edge Width, W = 30.00 ft

Curb‐to‐Curb Width, w = 26.67 ft

Skew Angle, q = 30.00 °

Barrier Width, Bw = 20.00 in Use smallest barrier width

WIDTH OF PRIMARY STRIP PER TABLE 4.6.2.1.3‐1 (ONLY APPLICABLE IF SPAN LENGTH ≤ 15 FEET)

Positive Moment

Width of Primary Strip, wp+ = 26.0 + 6.6 * L Cast‐in‐place, either parallel or perp.

Width of Primary Strip, wp+ = 26.0 + 6.6 * 39.25 = 285.05 in

Interior Strip: Single Lane Distribution Factor for Moment and Shear

Multiple Presence Factor, m1 = 1.20 Table 3.6.1.1.2‐1

Width of Primary Strip with Multi‐presence Factor, w1 = wp+ / m1 = 285.05 in / 1.20 = 237.54 in

Single Lane, Positive Moment Region, DF+1 = WA / w1 = 12.00 in / 237.54 in = 0.051

Interior Strip: Multi‐Lane Distribution Factor for Moment and Shear

No. of Design Lanes, NL = w / 12 = 2 Lane(s)

Multiple Presence Factor, mM = 1.00 Table 3.6.1.1.2‐1

Width of Primary Strip with Multi‐presence Factor, wM = wp+ / mM = 285.05 in / 1.00 = 285.05 in

Multi‐Lane, Positive Moment Region, DF+M = WA / wM = 12.00 in / 285.05 in = 0.042

EQUIVALENT WIDTH BASED ON 4.6.2.3

Skew Reduction Factor

r = 1.05 ‐ 0.25 * tan( q) ≤ 1.00 = 0.906 4.6.2.3‐3

Interior Strip: Single Lane Distribution Factor for Moment and Shear (4.6.2.3)

Modified Span Length, L1 ≤ 60 = 39.25 ft

Modified Edge‐to‐Edge Width, W1 ≤ 30 = 30.00 ft

Equivalent Width, EI1 = 10.0 + 5.0 * ( L1 * W1 ) ^ 0.5 4.6.2.3‐1

Equivalent Width, EI1 = 10.0 + 5.0 * ( 39.25 * 30.00 ) ^ 0.5 = 181.57 in C4.6.2.3

Distribution Factor, DF1 = r * ( WA / EI1 ) = 0.906 * ( 12.00 in / 181.57 in ) = 0.060

VERSION 6.2

110

Interior Strip: Multi‐Lane Distribution Factor for Moment and Shear (4.6.2.3)




No. of Design Lanes, NL = w / 12 = 2 Lane(s) 3.6.1.1.1

Use the Lesser of the two values for E IM :

Equivalent Width, EIM1 = 84.0 + 1.44 * ( L1 * W1 ) ^ 0.5 4.6.2.3‐2

Equivalent Width, EIM1 = 84.0 + 1.44 * ( 39.25 * 30.00 ) ^ 0.5 = 133.41 in C4.6.2.3

OR

Equivalent Width, EIM2 = 12.0 * W / NL 4.6.2.3‐2

Equivalent Width, EIM2 = 12.0 * ( 30.00 / 2 ) = 180.00 in

Equivalent Width, EIM = MIN( EIM1 , EIM2 ) = MIN( 133.41 in, 180.00 in ) = 133.41 in

Distribution Factor, DFM = r * ( WA / EIM ) = 0.906 * ( 12.00 in / 133.41 in ) = 0.081

Exterior Strip: Single Lane Distribution Factor for Moment and Shear (4.6.2.1.4b)

Use the minimum strip width, wMIN, from either Table 4.6.2.1.3‐1 (if applicable) or 4.6.2.3:

Strip Width from Table 4.3.2.1.3‐1, w1 = N/A

Strip Width from 4.6.2.3, EI1 = 181.57 in

Strip Width from 4.6.2.3, EIM = 133.41 in

Min. Strip Width, wMIN = MIN( w1, EI1, EIM ) = 133.41 in

Use the Minimum of the three values for E E :

Effective Width, EE1 = Bw + 12 + 0.25 * wMIN = 20.00 + 12 + 0.25 * ( 133.41 in ) = 65.35 in

OR

Effective Width, EE2 = 0.5 * wMIN = 0.5 * ( 133.41 in ) = 66.71 in 4.6.2.1.4c

OR

Effective Width, EE3 = 72 72.00 in

Effective Width, EE = MIN ( EE1, EE2, EE3 ) = MIN( 65.35 in, 66.71 in, 72.00 in ) = 65.35 in

Distribution Factor, DF1 = r * ( WA / EE ) * 0.5 = 0.906 * ( 12.00 in / 65.35 in ) * 0.5 = 0.083 **

**Distribution factor has been multiplied by 0.5 due to the fact that an exterior strip is assumed to support one line of

wheels and a portion of the lane where appropriate per 4.6.2.1.4b.

VERSION 6.2

111

MOMENT AND SHEAR DISTRIBUTION FACTOR SUMMARY

Ext. or Single Multi‐

Int. Slab Lane Lane

Interior N/A N/AInterior 0.060 0.081Exterior 0.083 0.083

Single‐Lane Distribution Factor for Deflection

No. of Design Lanes, NL1 = 1 Lane

Lane width, WL = 12.00 ft 3.6.1.1.1

Width of Slab Analyzed, WA = 1.00 ft


Single Lane, Deflection Distribution Factor, DFD1 = m1 * NL1 / ( NL1 * WL / WA )

DFD1 = 1.2 * ( 1 lanes ) / ( 1 lanes * 12.00 ft / 1.00 ft ) = 0.100

Multi‐Lane Distribution Factor for Deflection

No. of Design Lanes, NLM = 2 Lane(s)**

Lane width, WL = 12.00 feet 3.6.1.1.1

Width of Slab Analyzed, WA = 1.00 feet


Multi-Lane, Deflection Distribution Factor, DFDM = m1 * NLM / ( NLM * WL / WA )

DFDM = 1.0 * ( 2 lanes ) / ( 2 lanes * 12.00 ft / 1.00 ft ) = 0.083

4.6.2.1.4b

***NOTE: USE ENGINEERING JUDGMENT TO DETERMINE IF ONLY ANALYZING AN INTERIOR SLAB IS ACCEPTABLE OR IF

THE EXTERIOR SLAB SHOULD BE CONSIDERED AS WELL. DECISION WILL BE BASED ON DISTRIBUTION FACTORS,

REINFORCEMENT SPACING AT EXTERIOR EDGE AS COMPARED TO THE REINFORCEMENT SPACING OF THE INTERIOR

SLAB, AND THE CONDITION OF THE EXTERIOR EDGE OF THE SLAB PER THE INSPECTION REPORT.***

**For multi‐lane, 2 Lanes will always control since value is in the denominator. Therefore, use 2 lanes.

AASHTO

Reference

Table 4.6.2.1.3-1 → DOES NOT APPLY SINCE SPAN LENGTH > 15 ft per 4.6.2.1.2

4.6.2.3

VERSION 6.2

112

LRFD Live Load Distribution Factor Calculation for Span B

Note: All References taken from AASHTO LRFD Bridge Design Specifications, 4th ed (2007 with 2008 Interims)

INPUT

Physical Span Length, L = 39.00 ft

Width of Slab Analyzed, WA = 12.00 in


Curb‐to‐Curb Width, w = 26.67 ft

Skew Angle, q = 30.00 °

Barrier Width, Bw = 20.00 in Use smallest barrier width

WIDTH OF PRIMARY STRIP PER TABLE 4.6.2.1.3‐1 (ONLY APPLICABLE IF SPAN LENGTH ≤ 15 FEET)

Positive Moment

Width of Primary Strip, wp+ = 26.0 + 6.6 * L Cast‐in‐place, either parallel or perp.

Width of Primary Strip, wp+ = 26.0 + 6.6 * 39.00 = 283.40 in

Interior Strip: Single Lane Distribution Factor for Moment and Shear


Width of Primary Strip with Multi‐presence Factor, w1 = wp+ / m1 = 283.40 in / 1.20 = 236.17 in

Single Lane, Positive Moment Region, DF+1 = WA / w1 = 12.00 in / 236.17 in = 0.051

Interior Strip: Multi‐Lane Distribution Factor for Moment and Shear

No. of Design Lanes, NL = w / 12 = 2 Lane(s)


Width of Primary Strip with Multi‐presence Factor, wM = wp+ / mM = 283.40 in / 1.00 = 283.40 in

Multi‐Lane, Positive Moment Region, DF+M = WA / wM = 12.00 in / 283.40 in = 0.042

EQUIVALENT WIDTH BASED ON 4.6.2.3

Skew Reduction Factor

r = 1.05 ‐ 0.25 * tan( q) ≤ 1.00 = 0.906 4.6.2.3‐3

Interior Strip: Single Lane Distribution Factor for Moment and Shear (4.6.2.3)



Equivalent Width, EI1 = 10.0 + 5.0 * ( L1 * W1 ) ^ 0.5 4.6.2.3‐1

Equivalent Width, EI1 = 10.0 + 5.0 * ( 39.00 * 30.00 ) ^ 0.5 = 181.03 in C4.6.2.3

Distribution Factor, DF1 = r * ( WA / EI1 ) = 0.906 * ( 12.00 in / 181.03 in ) = 0.060

VERSION 6.2

113

Interior Strip: Multi‐Lane Distribution Factor for Moment and Shear (4.6.2.3)




No. of Design Lanes, NL = w / 12 = 2 Lane(s) 3.6.1.1.1

Use the Lesser of the two values for E IM :

Equivalent Width, EIM1 = 84.0 + 1.44 * ( L1 * W1 ) ^ 0.5 4.6.2.3‐2

Equivalent Width, EIM1 = 84.0 + 1.44 * ( 39.00 * 30.00 ) ^ 0.5 = 133.26 in C4.6.2.3

OR

Equivalent Width, EIM2 = 12.0 * W / NL 4.6.2.3‐2

Equivalent Width, EIM2 = 12.0 * ( 30.00 / 2 ) = 180.00 in

Equivalent Width, EIM = MIN( EIM1 , EIM2 ) = MIN( 133.26 in, 180.00 in ) = 133.26 in

Distribution Factor, DFM = r * ( WA / EIM ) = 0.906 * ( 12.00 in / 133.26 in ) = 0.082

Exterior Strip: Single Lane Distribution Factor for Moment and Shear (4.6.2.1.4b)

Use the minimum strip width, wMIN, from either Table 4.6.2.1.3‐1 (if applicable) or 4.6.2.3:

Strip Width from Table 4.3.2.1.3‐1, w1 = N/A

Strip Width from 4.6.2.3, EI1 = 181.03 in

Strip Width from 4.6.2.3, EIM = 133.26 in

Min. Strip Width, wMIN = MIN( w1, EI1, EIM ) = 133.26 in

Use the Minimum of the three values for E E :

Effective Width, EE1 = Bw + 12 + 0.25 * wMIN = 20.00 + 12 + 0.25 * ( 133.26 in ) = 65.31 in

OR

Effective Width, EE2 = 0.5 * wMIN = 0.5 * ( 133.26 in ) = 66.63 in 4.6.2.1.4c

OR

Effective Width, EE3 = 72 72.00 in

Effective Width, EE = MIN ( EE1, EE2, EE3 ) = MIN( 65.31 in, 66.63 in, 72.00 in ) = 65.31 in

Distribution Factor, DF1 = r * ( WA / EE ) * 0.5 = 0.906 * ( 12.00 in / 65.31 in ) * 0.5 = 0.083 **

**Distribution factor has been multiplied by 0.5 due to the fact that an exterior strip is assumed to support one line of

wheels and a portion of the lane where appropriate per 4.6.2.1.4b.

VERSION 6.2

114

MOMENT AND SHEAR DISTRIBUTION FACTOR SUMMARY

Ext. or Single Multi‐

Int. Slab Lane Lane

Interior N/A N/AInterior 0.060 0.082Exterior 0.083 0.083

Single‐Lane Distribution Factor for Deflection

No. of Design Lanes, NL1 = 1 Lane

Lane width, WL = 12.00 ft 3.6.1.1.1

Width of Slab Analyzed, WA = 1.00 ft


Single Lane, Deflection Distribution Factor, DFD1 = m1 * NL1 / ( NL1 * WL / WA )

DFD1 = 1.2 * ( 1 lanes ) / ( 1 lanes * 12.00 ft / 1.00 ft ) = 0.100

Multi‐Lane Distribution Factor for Deflection

No. of Design Lanes, NLM = 2 Lane(s)**

Lane width, WL = 12.00 feet 3.6.1.1.1

Width of Slab Analyzed, WA = 1.00 feet


Multi-Lane, Deflection Distribution Factor, DFDM = m1 * NLM / ( NLM * WL / WA )

DFDM = 1.0 * ( 2 lanes ) / ( 2 lanes * 12.00 ft / 1.00 ft ) = 0.083

4.6.2.1.4b

***NOTE: USE ENGINEERING JUDGMENT TO DETERMINE IF ONLY ANALYZING AN INTERIOR SLAB IS ACCEPTABLE OR IF

THE EXTERIOR SLAB SHOULD BE CONSIDERED AS WELL. DECISION WILL BE BASED ON DISTRIBUTION FACTORS,

REINFORCEMENT SPACING AT EXTERIOR EDGE AS COMPARED TO THE REINFORCEMENT SPACING OF THE INTERIOR

SLAB, AND THE CONDITION OF THE EXTERIOR EDGE OF THE SLAB PER THE INSPECTION REPORT.***

**For multi‐lane, 2 Lanes will always control since value is in the denominator. Therefore, use 2 lanes.

AASHTO

Reference

Table 4.6.2.1.3-1 → DOES NOT APPLY SINCE SPAN LENGTH > 15 ft per 4.6.2.1.2

4.6.2.3

VERSION 6.2

115

APPENDIX E: VDOT LRFR RATING FORM

116

Page 1 of 2

LOAD RATING SUMMARY FORM FOR STRUCTURES

Rte.: 00061, Clear Fork Creek Road

Signature: ____________________ Name: ______________ Date:______

Over: Clear Fork Creek #2

Va. Str. No.: 1032 Fed. ID: 02975

County: Bland District: Bristol

Rated By: ABC Date: 08/01/11 Checked By: XYZ Date: 08/17/11

VDOT Reviewer: ____________

Calculation Tools/Method Used: Virtis 6.2 – Virtis LRFR Engine Basis for Rating: Conversion to LRFR

GVW

(TONS) RATING

CONTROLLING

MEMBERS CONTROLLING LOCATION (FT)

CONTROLLING FORCE

DESIGN LOAD FACTOR ***HL-93 (INV) N/A 1.79 Span A&C: Int. Slab 19.63 STR I – Conc. Flexure ***HL-93 (OPR) N/A 2.32 Span A&C: Int. Slab 19.63 STR I – Conc. Flexure

TONS HS-20 (INV) 36 80 Span A&C: Int. Slab 19.63 STR I – Conc. Flexure HS-20 (OPR) 36 104 Span A&C: Int. Slab 19.63 STR I – Conc. Flexure

LEGAL LOADS TONS ** VA Type 3 27 106 Span A&C: Int. Slab 23.55 STR I – Conc. Flexure

VA Type 3S2 40 134 Span A&C: Int. Slab 19.63 STR I – Conc. Flexure *, ***LANE 40 --- --- --- ---

PERMIT LOAD TONS BP-90 45 117 Span A&C: Int. Slab 19.63 STR II – Conc. Flexure

BP-115 57.5 147 Span A&C: Int. Slab 19.63 STR II – Conc. Flexure SH VEHICLES TONS **

NRL 40 91 Span A&C: Int. Slab 19.63 STR I – Conc. Flexure SU4 27 81 Span A&C: Int. Slab 19.63 STR I – Conc. Flexure SU5 31 88 Span A&C: Int. Slab 19.63 STR I – Conc. Flexure SU6 34.75 89 Span A&C: Int. Slab 19.63 STR I – Conc. Flexure SU7 38.75 93 Span A&C: Int. Slab 19.63 STR I – Conc. Flexure

* **

*** ****

Not applicable for single spans less than and equal to 200 feet. FOR LFR or ASD: Denote if it is a mid range or operating level for posting and provide the safe posting load. Not applicable for LF/AS rating methods. Denotes does not meet the rating requirements.

Consulting Firm, Inc. 117

Page 2 of 2

LOAD RATING SUMMARY FORM FOR STRUCTURES

INSPECTION REPORT USED FOR THIS RATING: 0101032-000000000002975 11/18/2009 ASSUMPTIONS/COMMENTS BY LOAD RATING ENGINEER: Bridge No. 02975 – Three Simple Span Reinforced Concrete Slab Bridge

1. Plan 265-47 was used for the analysis.

2. 1.0’ wide section of slab analyzed.

3. Sacrificial wearing thickness = 0.50”.

4. There is no deterioration/other changes to warrant an IR structure.

Latest version of this form is SB502 and is available on the VDOT Structure and Bridge web site under “Useful Information.”

118

APPENDIX F: STRENGTH LIMIT STATE

RATING FACTOR AND TONNAGE

CALCULATIONS

119

VIRGINIA DEPARTMENT OF TRANSPORTATION

SIMPLE SPAN REINFORCED CONCRETE SLAB

LOAD RATING EXAMPLE

Overview References

The Purpose of this Mathcad sheet is to calculaterating factors and tonnages for vehicle configurationsin the Virginia Department of Transportation Structureand Bridge Division's Instructional and InformationalMemorandum IIM-S&B-86.

This sheet does not provide any analysiscalculations, but only provides calculations for ratingfactors and load ratings using output from Virtis 6.2using the Virtis LRFR engine for a simple spanreinforced concrete slab bridge. All calculations arefor the strength limit state.

AASHTO 2011, The Manual for Bridge Evaluation,Second Edition

AASHTO 2007 with 2008 Interim Revisions, LRFDBridge Design Specifications, 4th Edition

VDOT Structure and Bridge Division Instructional andInformational Memorandum 86, May 4, 2011(IIM-S&B-86)

Note

Input cells are highlighted in yellow.

VDOT Vehicle Configuration Tonnages

Design Vehicles Permit Vehicles Specialized Hauling Vehicles

HS20 36 ton BP90 45 ton NRL 40 ton

BP115 57.5 ton SU4 27 tonLegal VehiclesSU5 31 ton

VAType3 27 tonSU6 34.75 ton

VAType3S2 40 tonSU7 38.75 ton

Condition Factor

Structural Condition of Member Condition Factor

Good/Satisfactory/Fair 1.00

Poor 0.85

ϕc 1.00

Note: Table taken from IIM-S&B-86 with onealteration. The condition factor for the Poorstructural condition was changed from 0.90to 0.85.

This change was made due to the fact thatthe default value for the poor condition factorin Virtis is 0.85 and cannot be modified bythe user.

120



LOAD RATING EXAMPLE

Reinforced Concrete Slab Flexural Capacity

1.

2.

Reinforced concrete slabs and slab bridges designed in conformance with AASHTO specifications maybe considered satisfactory for shear. Also, shear need not be checked for design and legal load ratings ofconcrete members. Therefore, shear will be ignored for this rating example. The concrete slab will berated for moment and the flexural capacity will be taken from the Virtis program.

Reference AASHTO LRFD Bridge Design 5.14.4.1 and 6a.5.9.

Flexural CapacityTo find the capacity:

Cflex 259.14 kip ft 1. After analyzing the desired beam, highlight the MEMBERALTERNATIVE of interest. For the example, the interior slab in SpanA&C controlled the ratings.

2. Left click the View Spec Check icon.

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LOAD RATING EXAMPLE

3. Left click the desired location along the span length and then double click 5.7.3.2 Flexural Resistance(Reinforced Concrete) from the Specification Reference column. Typically, the controlling location isat midspan for this bridge type.

4. The specification check detail window will appear. Scroll down and the capacity for the slab can befound under the Mr = Phi * Mn column.

Note: Moment capacity is the same for alllimit states and vehicles at a givenlocation.

122



LOAD RATING EXAMPLE

Dead Load Moments To find the dead load moments:

DC1 57.77 kip ft 1. After analyzing the desired beam, highlight the MEMBER ALTERNATIVE ofinterest.

DC2 5.01 kip ft

DC DC1 DC2

DC 62.78 kip ft

DW 0.0 kip ft

2. Left click the View Analysis Report icon. 3. The Analysis Results window will appear. SelectDead Load Actions from the Report Type dropdown menu to view the dead load moments.

4. The user can view the DC1, DC2, and DW loads by using the Dead Load Case drop down menu.

123



LOAD RATING EXAMPLE

Live Load Moments

Design Vehicles Permit Vehicles Specialized Hauling Vehicles

HL93LL 57.45 kip ft BP90LL 49.60 kip ft NRLLL 56.13 kip ft

HS20LL 45.95 kip ft BP115LL 53.80 kip ft SU4LL 42.65 kip ft

SU5LL 45.07 kip ftLegal Vehicles

VAType3LL 32.28 kip ft SU6LL 50.04 kip ft

VAType3S2LL 38.50 kip ft SU7LL 53.32 kip ft

To find the live load moments:

1. After analyzing the desired beam, highlight the MEMBER ALTERNATIVE of interest.

2. Left click the View Analysis Report icon. 3. The Analysis Results window will appear.Select Live Load Actions from the ReportType drop down menu to view the live loadmoments.

124



LOAD RATING EXAMPLE

4. The user can view the live loads for the various vehicles by using the Live Load drop down menu.

Note: User should also use the Live Load Type drop down menu for each vehicle and use load typewhich produces the greatest positive moment at the point of interest.

125



LOAD RATING EXAMPLE

Live Load Factors

All rating factors except for design loads are dependent upon the average daily truck traffic, ADTT.Therefore, rating factors for legal loads, permit loads, and specialized hauling vehicles will be interpolatedby the Mathcad sheet based upon the ADTT inputted by the user.

ADTT 5

Design Load Factors

Table 6A.4.3.2.2-I – Load Factors for Design Load: γL

Evaluation Level Load Factor

Inventory 1.75

Operating 1.35

See AASHTO 2011, The Manual forBridge Evaluation, Second Edition,Table 6A.4.2.2-1

γDESinv 1.75

γDESopr 1.35

Legal Load Factors

See AASHTO 2011, The Manual forBridge Evaluation, Second Edition,6A.4.4.2.3a-1

Table 6A.4.4.2.3a-1 – Generalized Live Load Factors, γL for

for Routine Commercial Traffic

Traffic Volume (One direction)

Load Factor for Type 3, Type 3S2, Type 3-3 and

Lane Loads

Unknown 1.80

ADTT ? 5000 1.80

ADTT = 1000 1.65

ADTT ? 100 1.40

Linear interpolation is permitted for other ADTT.

γLegal 1.40

(interpolated)

Specialized Hauling Load Factors

Virtis categorizes the specialized hauling vehicles as legal loads. Therefore, legal load factors will beused for these vehicles.

See AASHTO Manual for BridgeEvaluation 2011, Second Edition,Table 6A.4.4.2.3b-1

γSHV γLegal

γSHV 1.40

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LOAD RATING EXAMPLE

Permit Load Factors

See AASHTO 2011, The Manual for Bridge Evaluation, Second Edition, Table 6A.4.5.4.2a-1

Table 6A.4.5.4.2a-1 – Permit Load Factors: γL

Up to 100 kips ? 150 kips

> 5000 1.80 1.30

= 1000 1.60 1.20

< 100 1.40 1.10

a DF = LRFD distribution factor. When one-lane distribution factor is used, the built-in multiple presence factor should be divided

out.

b For routine permits between 100 kips and 150 kips, interpolate the load factor by weight and ADTT value. Use only axle weights

on the bridge.

Routine or Annual

Unlimited Crossings

Mix with traffic (other vehicles may be on the bridge)

Two or more lanes

Load Factor by

Permit Weightb

Permit Type Frequency Loading Condition DFa

ADTT (one direction)

γP90 1.40 γP115 1.31 Note: For the BP115 vehicle, interpolation isrequired based on the ADTT and thevehicle tonnage. Therefore, use:

(interpolated) (interpolated)

ADTT (one direction)

Interpolated Load Factor

> 5000 1.65

= 1000 1.48

< 100 1.31

Note: The load factor for theBP90 vehicle iscalculated byinterpolation usingthe ADTT columnand the Up to 100kips column in Table6A.4.5.4.2a-1.

The load factor for the BP115 vehicleis calculated by interpolation using theADTT column and the InterpolatedLoad Factor column in the tableabove.

The Interpolated Load Factor columnabove would be placed between the Upto 100 kips and the > or = 150 kipscolumn in Table 6A.4.5.4.2a-1.

127



LOAD RATING EXAMPLE

Rating Factor Calculations

HL-93 (Inventory) HL-93 (Operating)

HL93RFinv

ϕc Cflex 1.25 DC 1.50 DW

γDESinv HL93LL HL93RFopr


γDESopr HL93LL

HL93RFinv 1.797 HL93RFopr 2.329

HS-20 (Inventory) HS-20 (Operating)

HS20RFinv


γDESinv HS20LL HS20RFopr


γDESopr HS20LL

HS20RFinv 2.247 HS20RFopr 2.912

VA Type 3 VA Type 3S2

VAType3RF


γLegal VAType3LL VAType3S2RF


γLegal VAType3S2LL

VAType3RF 3.998 VAType3S2RF 3.352

BP-90 BP-115

BP90RF


γP90 BP90LL BP115RF


γP115 BP115LL

BP90RF 2.602 BP115RF 2.563

NRL SU4

NRLRF


γSHV NRLLL SU4RF


γSHV SU4LL

NRLRF 2.299 SU4RF 3.026

SU5 SU6

SU5RF


γSHV SU5LL SU6RF


γSHV SU6LL

SU5RF 2.863 SU6RF 2.579

SU7 Note: Due to Virtis rounding the results for capacity,dead load, and live load moments, the Mathcad resultsmay vary slightly from the Virtis results.SU7RF


γSHV SU7LL

SU7RF 2.42

128



LOAD RATING EXAMPLE

Load Rating Tonnage Calculations

HL-93 (Inventory) HL-93 (Operating)

N/A N/A

HS-20 (Inventory) HS-20 (Operating)

HS20LRinv = HS20RFinv . HS20 HS20LRopr = HS20RFopr . HS20

HS20LRinv 80 ton HS20LRopr 104 ton

VA Type 3 VA Type 3S2

VAType3LR = VAType3RF . VAType3 VAType3S2LR = VAType3S2RF . VAType3S2

VAType3LR 107 ton VAType3S2LR 134 ton

BP-90 BP-115

BP90LR = BP90RF . BP90 BP115LR = BP115RF . BP115

BP90LR 117 ton BP115LR 147 ton

NRL SU4

NRLLR = NRLRF . NRL SU4LR = SU4RF . SU4

NRLLR 91 ton SU4LR 81 ton

SU5SU6

SU5LR = SU5RF . SU5 SU6LR = SU6RF . SU6

SU5LR 88 ton SU6LR 89 ton

SU7 Note: Due to Virtis rounding the results for capacity,dead load, and live load moments, the Mathcad resultsmay vary slightly from the Virtis results.

SU7LR = SU7RF . SU7

SU7LR 93 ton

129

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