cip box girder training example

7/30/2019 Cip Box Girder Training Example

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LRFD Design of California Bridges

Kosal Krishnan October 2, 2007 - 1 -


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FIGURE

Ex-1-MassachusettsAveOC(Replace)GeneralP

lanandElevation


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FIGURE

Ex-2-MassachusettsAveOC(Replace)TypicalSection


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FIGURE

Ex-3-MassachusettsAveOC(Replace)BentDetails1of2


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FIGURE

Ex-4-MassachusettsAveOC(Replace)BentDetails2of2


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FIGURE

Ex-5-Mass

achusettsAveOC(Replace)G

irderDetails


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FIGURE

Ex-6-Mass

achusettsAveOC(Replace)G

irderLayout


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Massachusetts Ave OC (Replace) Example Problem

Step 1: Com plete the Project Info rmatio n

The Projecttab allows you to enter general information about the project and select the analysisoptions, design specifications, units, and loss type. You can return to this tab at any time and

make changes.

FIGURE 1-1 Project Tab

Complete the Projecttab by entering the information shown in Fig. 1-1.

For this example, you will be analyzing and designing the concrete box girder using the FullWidth Only option.

Step 2: Def ine the Br idge A l ignment

GEOMETRY TAB

The Geometry tab allows you to input the physical properties of the bridge, including bridgealignment, layout, cross section information, and pier/column properties. Using this tab, you cancreate, modify, or delete elements of your bridge description.


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FIGURE 1-2 Geometry Tab

BRIDGE ALIGNMENT DIALOG BOX

The Bridge Alignmentdialog box allows you to define a bridges alignment by creating, modifying,or deleting alignment tangents and/or curve segments.NOTE: Refer to Fig. Ex-2: Plan View for additional data input.


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FIGURE 1-3 Bridge Alignment Dialog Box

Begin by entering the beginning station equal to 19+00.603. Next, enter segment 1, tangent start

direction equal to N 26 50 50.00 W and end station equal to 63+60.2461. Click the Add Curvebutton and enter the data as shown in Fig. 1-3. Next, click the Add Tangent button and enter thedata as shown in Fig. 1-3. Next, click the Add Curve button and enter the data shown in Fig. 1-3.

Step 3: Def ine the Br idg e Connect ions

GEOMETRY TAB

Once you have defined the bridge alignment, you can create and/or modify the bridgeconnections by clicking the Layout button on this tab to open the Bridge Component Layoutdialog box.

BRIDGE COMPONENT LAYOUT DIALOG BOX

The Bridge Component Layoutdialog box allows you to define the physical location, bearing, andconnection types for abutments, piers (bents), and span hinges as well as the stationing for thebegin bridge and the end bridge.


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NOTE: Refer to Fig. Ex-2: Plan View for additional data input.

FIGURE 1-4 Bridge Component Layout Dialog Box

This bridge has two abutments, four piers, and no hinges. The program automatically createsrows for the beginning and end of the bridge. Layout the bridge as shown in Fig. 1-4. When youare done, click the OK button to return to the Geometrytab.

Step 4: Define the Cross Section L ayou t and Materials

GEOMETRY TAB

Once you have defined the bridge layout, you can create and/or modify the superstructure crosssection and layout by clicking the Cross Section button on this tab to open the Cross SectionLayoutdialog box.

CROSS SECTION LAYOUT DIALOG BOX

The Cross Section Layoutdialog box allows you to define the bridge cross section.

NOTE: Refer to Fig. Ex-3: Typical Section for additional data input.


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FIGURE 1-5 Cross Section Layout Dialog Box

This bridge has a constant depth with no soffit or web flares. By default, the program creates a

beginning section. You should define the section properties for the begin section first by clickingthe Section button under the Section Deffield to open the Multi-Cell CIP Box Section dialog box.

MULTI-CELL CIP BOX SECTION DIALOG BOX

The Multi-Cell CIP Box Section dialog box allows you to define cross section dimensions.NOTE: Refer to Fig. Ex-3: Typical Section for additional data input.


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FIGURE 1-6. Multi-Cell CIP Box Section Dialog Box (Span 1)

Define the section properties by entering the dimensions as shown in Fig. 1-6. To define theconcrete material properties, click the Material button to open the Concrete Materialdialog box.

CONCRETE MATERIAL DIALOG BOX

This dialog box allows you to define the material for the superstructure cross section. Define thematerial properties for this bridge by entering the information as shown in Fig. 1-7. When you aredone, click the OK button to return to the Multi-Cell CIP Box Section dialog box.

NOTE: Refer to the Concrete Material Properties section of Problem Data.

FIGURE 1-7 Concrete Material Dialog Box (Cross Section)

You will need to define more section definitions to complete this problem.

MULTI-CELL CIP BOX SECTION DIALOG BOX

Once you have completed defining the material and section properties for this segment, click theOK button to return to the Cross Section Layoutdialog box.

CROSS SECTION LAYOUT DIALOG BOX

When you return to this dialog box, you need to define the remaining cross sections. Fig. T4-25through Fig. T4-32 represent the completed grid definitions for the bridge. To complete each ofthe nine section definitions, refer to the following tables. When you are done, click the OK buttonto return to the Geometrytab.


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NOTE: Refer to Fig. 1-3: Typical Section and Fig. 1-4: Girder Layout for additional data input.

FIGURE 1-8 Cross Section Layout Dialog Box (Span 1 Abutment Diaphragm)


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FIGURE 1-9 Cross Section Layout Dialog Box (Span 1 Completed)


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FIGURE 1-10 Cross Section Layout Dialog Box (Span 2 Completed)


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FIGURE 1-11 Cross Section Layout Dialog Box (Span 1 thru 5 Completed)

You will be utilizing the Recall section type to minimize the number of cross sections for thistutorial. The abutment diaphragms are input to simulate the diaphragm.

Step 5: Def ine the Piers and Column s

GEOMETRY TAB

Once you have defined the cross section layout and materials, you can create and/or modify thepiers and columns by clicking the Piers button on this tab to open the Pier and ColumnDefinitions dialog box.

PIER AND COLUMN DEFINITIONS DIALOG BOX

The Pier and Column Definitions dialog box allows you to define single or multicolumn piers(bents).

NOTE: Refer to Fig. Ex-3: Bent Details 1 of 2 for additional data input.


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FIGURE 1-12 Pier and Column Definitions Dialog Box

By default, CONBOX creates a pier with the name Typ2Col. Rename this pier to BENT 2 tomatch the pier referenced in the Bridge Component Layout dialog box in order to place the

defined pier at a stationing along the bridge. Note that not all piers need to be referenced in theBridge Component Layoutdialog box, thus allowing you to define a variety of different piers andselectively use them.

For this tutorial, however, the pier/bent contains four columns that are among the predefinedprismatic column types; however, a user-defined column type is created by clicking the ColumnTypes button to open the Column Definition dialog box.

COLUMN DEFINITION DIALOG BOX

This dialog box allows you to create, modify, or delete nonprismatic column shapes.NOTE: Refer to Fig. Ex-4: Bent Details 2 of 2 for additional data input.


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FIGURE 1-13 Column Definition Dialog Box (Mass_Col)


Specify the column length by entering 8.97 (Col. 1) and 8.97 (Col. 2,3 and 4) in the Len fieldlocated in the Columns for Pier Definition grid. Select Mass_Col from the Column Type drop-

down list, Pin from the Supportdropdown list. Also, the columns in this pier are 3.067 m apart.Next you need to define the concrete material properties for the column by clicking the Materialbutton in the grid to open the Concrete Materialdialog box.

CONCRETE MATERIAL DIALOG BOX

This dialog box allows you to define the concrete material for the appropriate column by enteringthe information as shown in Fig. 1-14.

FIGURE 1-14 Concrete Material Dialog Box

NOTE: Only the appropriate concrete material properties will be available.When you are done, click the OK button to return to the Pier and Column Definitions dialog box.


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Once you have completed defining Bent 2, complete the definitions for Bents 3, 4 and 5 bycopying the definition to Bent 2 to keep the same concrete material properties. Refer to thefollowing table for additional data input.

Col. # Spacing (m) Length (m) Column Type SupportBent 2 (Integral)

1 3.067 8.97 Mass_Col Pin



4 - 8.97 Mass_Col PinBent 3 (Integral)






2 3.067 9.46 Mass_Col Pin3 3.067 9.46 Mass_Col Pin





4 - 8.39 Mass_Col Pin

When you are done, click the OK button to return to the Geometrytab.

At this point, it would be a good idea to save your project. Select the Save As option from the Filemenu. Enter the file name you want to save your data to (e.g., Massachusetts Ave OC Replace)

in the File Name field and click the Save button. The default extension is *.cbx.

Step 6: Define the Post-Tensio n Layo ut

MODEL TAB

The Model tab allows you to modify the plane frame analytical model by specifying additionaldetails about the superstructure, the tendons, the longitudinal rebar, and the stirrups.


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FIGURE 1-15 Model Tab

The span distances, bearing, and connection information was entered previously in the BridgeComponent Layout dialog box (Layout button on the Geometry tab). Since you will not be making

any changes to this information, you can skip the Superstructure button.

You can define the post-tension layout and tendon information for the full section by clicking theTendons button to open the Tendon Definitions dialog box.

TENDON DEFINITIONS DIALOG BOX

The dialog box allow you to define the post-tension layout and tendon information. Enter the post-tensioning information as shown in Fig. 1-16. Refer to the following table for Path Datainformation.

CONBOX computes the Required Jacking Force (P-Jack) and Concrete Strength at Initial(Required fci). This information can be found in the Design Results screen located in the Design

tab. For this example, however, you will proceed by specifying the post-tensioning layoutinformation according to the contract plans.


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FIGURE 1-16 Tendon Definitions Dialog Box

NOTE: Refer to the Tendon Profile Diagrams (Fig. Ex-5) for additional data input.

Location SpanNumber

Distance(%)

Top orBottom

Offset(mm)

VariationType

POC

1 1 0 Top 595

2 1 40 Bottom 760 Par-E

3 1 100 Top 380 Par-D 0.8333

4 2 50 Bottom 305 Par-D 0.1667

5 2 100 Top 380 Par-D 0.8333

6 3 50 Bottom 455 Par-D 0.1667

7 3 100 Top 380 Par-D 0.8333

8 4 50 Bottom 305 Par-D 0.1667

9 4 100 Top 380 Par-D 0.8333

10 5 60 Bottom 610 Par-D 0.1667

11 5 100 Top 595 Par-S

Once you completed the tendon definitions, click the OK button to return to the Modeltab.

Step 7: Def ine the Dead Loads for the Analysis

LOADS/ANALYSIS TAB

The Loads/Analysis tab allows you to specify load combinations (LRFD) to be used in theanalysis. For this tutorial, you will be adding the following loads:


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Dead Loads: Intrinsic Self Weight, Integral Bent Cap Weight Superimposed Dead Loads: Barrier, Future AC Overlay Temperature Loads: Uniform Temperature Live Loads: HL93 Multispan, P5-P15 Permit LL

NOTE: Refer to the Problem Data for additional data input.

FIGURE 1-17 Loads/Analysis Tab

Select the Initial analysis case and define the Intrinsic Self-Weight load by right-clicking the DeadLoad/DC Group option on the right panel and selecting Add DC/DL. Double-click the DeadLoad-1 (Initial) load to open the Dead Loads dialog box.

DEAD LOADS DIALOG BOX (INTRINSIC SELF WEIGHT)

This dialog box allows you to define the dead load for the analysis. You can define the intrinsicself-weight by selecting the Include Self-Weight option as shown in Fig. 1-18.


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FIGURE 1-18 Dead Loads Dialog Box (Intrinsic Self-Weight)

Once you are done, click the OK button to return to the Loads/Analysis tab. Define the DeckFalsework Load by right-clicking the Dead Load/DC Group option on the right panel and

selecting Add DC/DL. Double-click the load to open the Dead Loads dialog box.

DEAD LOADS DIALOG BOX (INTEGRAL BENT CAP)

Define the additional load due to the integral bent cap by completing the information as shown inFig. 1-19.


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FIGURE 1-19. Dead Loads Dialog Box (Integral Bent Cap)

Once you are done, click the OK button to return to the Loads/Analysis tab.

Step 8: Def ine the Super impos ed Dead L oads for the An alysis

Once you have defined the Dead Loads, notice that all two loads have been added to the rightpanel and are now represented in the graphic window for the bridge as shown in Fig. 1-20.

NOTE: Refer to the Problem Data beginning for additional data input.


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FIGURE 1-20 Loads/Analysis Tab (Dead Loads Added)

Select the Final analysis case and define the Barrier Load by right-clicking the SuperimposedDead Load/DW Group option on the right panel and selecting Add DW/ADL. Double-click the

load to open the Dead Loads dialog box.

DEAD LOADS DIALOG BOX (BARRIER)

Define the Barrier Load by completing the information as shown in Fig. 1-21.


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FIGURE 1-21 Dead Loads Dialog Box (Barrier)

Once you are done, click the OK button to return to the Loads/Analysis tab. Define the Future ACOverlay Load by right-clicking the Superimposed Dead Load/DW Group option on the right-side

of the screen and selecting Add DW/ADL. Double-click the load to open the Dead Loads dialogbox.

DEAD LOADS DIALOG BOX (Fut. AC Overlay)

Define the Future AC Overlay Load by completing the information as shown in Fig. 1-22.


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FIGURE 1-22 Dead Loads Dialog Box (FWS)


Step 9: Def ine the Temperature Lo ads for th e An alysis

Once you have defined the Superimposed Dead Loads, notice that both loads have been addedto the right panel and are now represented in the graphic window for the bridge as shown in Fig.1-23.

NOTE: Refer to the Problem Data for additional data input.


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FIGURE 1-23 Uniform Temperature Load Dialog Box

Define the Uniform Temperature Load by right-clicking the Temperature Load Group option onthe right panel and selecting Add Uniform Temperature. Double-click the load to open the

Uniform Temperature Loaddialog box.

UNIFORM TEMPERATURE LOAD DIALOG BOX

Define the Uniform Temperature Load by completing the information as shown in Figure 1-24.

FIGURE 1-24 Uniform Temperature Load Dialog Box


Step 10: Def ine the Live Lo ads for the A nalysis

LOADS/ANALYSIS TAB


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After verifying the Uniform Temperature Load, select the Final w/o Sway analysis case andcheck the Live Loads by expanding the Live Load Group on the right panel. For LRFD, youneed to add the HL 93 Multispan load. Define this load by expanding the Live Load Grouplocated under Locked Library Loads. Select the predefined HL 93Multispan load, then drag anddrop it anywhere within the Tutor 5 Loads. Notice that this load is added to the Live Load Group.In the Live Load Group for this tutorial, double-click the HL 93 Multispan Load to open the LiveLoaddialog box.

NOTE: The Locked Library Loads can be viewed or modified by selecting Vehicle from theLibraries menu to open the Vehicle Library.

LIVE LOAD DIALOG BOX (HL 93 MULTISPAN LOAD)

This dialog box allows you to add or modify live loads for the analysis. Verify that the definition forthis load appears as shown in Fig. 1-25.

FIGURE 1-25 Live Load Dialog Box (HL 93 Multispan)


LIVE LOAD DIALOG BOX (P5-P15 PERMIT LL)

This dialog box allows you to add or modify live loads for the analysis. Verify that the definition forthis load appears as shown in Fig. 1-26.


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FIGURE 1-26 Live Load Dialog Box (P5-P15 PERMIT LL)


Step 11: Speci fy the Load Comb inat ion Factors for th e Analysis

LOADS/ANALYSIS TAB

LRFD uses different combination types for analysis: Strength I, Strength II, Service I, Service III.

To modify the combinations for the Initial case, select Initial from the Case drop-down list, selectthe SLD 1 (Initial) combination from the left panel, right-click and select Edit Combination toopen the LRFD Load Combination Factors dialog box.

LRFD LOAD COMBINATION FACTORS DIALOG BOX (SERVICE 1 (INITIAL))

Rename this combination to one more appropriate for LRFD and select the Service I combinationtype. Complete the load combination as shown in Fig. 1-27. Once you are done, click the OKbutton to return to the Loads/Analysis tab.


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FIGURE 1-27 LRFD Load Combination Factors Dialog Box


LOADS/ANALYSIS TAB

Notice that the dead loads are still included in this combination. Next, create the Service III loadcombination by right-clicking the left pane and selecting Add Combination to open the LRFDLoad Combination Factors dialog box.

LRFD LOAD COMBINATION FACTORS DIALOG BOX (SERVICE 3 (INITIAL))

Name this load combination Service 3 (Initial) and select the Service III combination type. Acceptall other defaults by clicking the OK button to return to the Loads/Analysis tab.

LOADS/ANALYSIS TAB

Once you have created the Service 3 (Initial) load combination, select the Self Weight load in the

right panel, then drag and drop it anywhere within the combination. Repeat this process again toadd the Integral Bent Cap load to the combination.

Repeat the steps defined above to define the rest of the combinations for the analysis. You caneither modify the existing loads or delete them and add new ones. For all load combinations,leave the parameters in the LRFD Load Combination Factors dialog box as the default. Refer tothe following table for additional input information.


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Defined Loads to Include

AASHTOCombination

Type

CombinationName

Purpose

SelfWt.

Int.BentCap

Barrier Fut. ACOverlay

UniformTemp.

HL93 -Multispan

P5-P15

Permi

Initial

Service I Service 1(Initial) fciDesignComp.StressCheck

X X

Service III Service 3(Initial)

Ten.StressCheck

X X

Final

Service I Service 1(Final)

fciDesignComp.Stress

Checkw/Temp.

X X X X X

Service III Service 3(Final)

Ten.StressCheckw/Temp.

X X X X X

Final w/oSway

Service I fcDesign

X X X X X X

Service III PTDesign

X X X X X X

Strength I StrengthDesign(Std.)

X X X X X X

Strength II StrengthDesign(Permit)

X X X X X X

Step 12: Check the Design Parameters

Select Design Parameters from the Settings menu to open the Design Parameters dialog box.This dialog box allows you to view and/or edit the settings of the design parameters.


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FIGURE 1-28 Design Parameters Dialog Box

Change the PS + Perm Tension Factor to 0 and the Flexure PT Resistance Factor to 0.95.Use the default numbers for all other allowable stress and resistance factors. When you are done,click the OK button to return to the program.

Step 13: Run the Analysis

LOADS/ANALYSIS TAB

You will use the program-computed live load distribution factors according to AASHTO; therefore,skip the Live Load Distribution Factors button.

After defining the load combinations, you can perform an analysis of the structure by clicking theRun Analysis button. After performing the analysis, the default analysis result text/graphic reportdisplays in theAnalysis Results screen.

ANALYSIS RESULTS SCREEN

This screen displays automatically after performing the analysis and presents you with theanalysis results.


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FIGURE 1-29 Analysis Results Screen (Text Format)

This screen allows you to view, print, or save (in text or Microsoft Excel formats) structureresponses to all loads, load cases, and load combination. Click to close this screen and return to

the Loads/Analysis tab.

Step 14: View the Design Results

DESIGN TAB

This tab allows you to verify the design results and assists you in designing the layout of yourrebar and stirrups, if necessary. After running the analysis, click the Design Results button toopen the Design Results screen.


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FIGURE 1-30 Design Tab

DESIGN RESULTS SCREEN

This screen displays automatically after computing the design and presents you with the designresults.


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FIGURE 1-31 Design Results Screen (Text Format)

This screen allows you to view, print, save, or copy (in text or Microsoft Excel formats)structure responses to all loads, load cases, and load combination. Click to close this screen and

return to the Loads/Analysis tab.

Step 15: Print th e Repo rts

The input of the Example problem is completed. To print the final output of the project, selectPrint from the File menu to open the Print Report Managerdialog box.

PRINT REPORT MANAGER

For this example, print to a file all the model reports, analysis results, design/check reports, andmiscellaneous reports as shown in Fig. 1-32. Click the Create Reports button to send theselected output to a text file.


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FIGURE 1-32 Print Report Manager

Following this page is a printout of select output for the Example problem according to the optionsselected above.

At this point, it would be a good idea to save your project. Select the Save As option from the Filemenu. Enter the file name you want to save your data to (e.g., MASSACHUSETTS AVE OCREPLACE) in the File Name field and click the Save button. The default extension is *.cbx.

cip box girder training example

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