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Bridge Design using the STAAD.Pro/Beava

1.0 Introduction………………………………………………….1

2.0 Creating the Bridge Geometry/Structural Analysis…………2

3.0 Generate AASHTO 2002 Maximum Response……………13

4.0 Bridge Design as Per AASHTO…………………………...31

5.0 Conclusion…………………………………………………36

1.0 Introduction

1. Maximum plate stresses, moment about the local x axis of a plate (Mx), moment about

2. Maximum support reactions to design isolated, pile cap, and mat foundations.

3. Maximum bending moment or axial force in a member used to design members as per

4. Maximum deflection at mid span.

2.0 Creating the Bridge Geometry/Structural Analysis

1. Open STAAD.pro with the default units of Kip-Ft and use the Space option.

2. Click the Next button and select the Add Beam mode. Click Finish.

3. The goal of the next few steps is to draw the stick model of the Bridge Structure (i.e. the

4. Click on the Snap Node/Beam button and draw the beams and the girders as shown

5. Click on Geometry->Intersect Selected Members->Highlight. STAAD.pro will highlight

6. The beams have been created. The columns will now be created using the translational

7. The deck of this bridge structure will be created in the following steps using the Generate

8. Select the Geometry->Generate Surface Meshing tool from the menu. Select four

9. 2ft x 2ft element size is adequate for this type of model. Hence input the parameters as

10. The mesh will be created. To view the mesh properly, you will need to click on the Setup

11. You should note that the girders and beams are automatically broken down into smaller

12. Select Geometry->Merge Selected Members to merge the split concrete beams.

13. By merging the beams together, the concrete column to beam connectivity is lost.

14. The geometry has been created. The properties and specifications have to be assigned.

2ft x 2ft Sections

2.044167 ft + 0.5 x 1ft = 3.544167 ft at both ends.

15. Click on the General->Property control tab on your left and click on the Section

16. Select the W24x103 section from the American W shape database and click on the Add

17. Select the W24x103 section that has been created. Click on the Select the Select-

18. Select the Define button on the right and select the Circle section profile. Input a 2ft

19. Select the Rectangle section profile and input 2ft in the YD and ZD input boxes. Press

20. Select the Cir 24 section that has been created. Click on the Select the Select->Beam

21. Select the Rect 24.00x24.00 section that has been created. Click on the Select the

22. Press the Thickness button the right and input 1ft in the Node 1 input box and press the

23. Select the newly create Plate Thickness entry in the Properties dialog box. Select all

24. Select the Spec sub-control tab on the left.

25. Press the Beam button. Select the Offset tab. Select the start option from the location

26. Press the Beam button. Select the Offset tab. Select the End option from the Location

27. Assign these specifications to the steel girders parallel to the x-axis. Select the START

28. Select the END LOCAL 0 -1.52208 0 specification that has been created. Click on the

29. Repeat Steps# 25 to 28 for the concrete beams but use a y-offset of -3.544167 ft at both

30. For the columns assign a local x-offset of 4.544167ft at the end connected to the

31. Click on the View->3D Rendering in the menu.

32. Select the General->Support tab on the left and click on the Create button in the right

33. Select the newly created S2 Support 2 entry and using the nodes cursor select nodes

16, 17, and 18. Click on the Assign button.

34. Select the General->Load tab on the left and click on Load Case Details on the right

35. Click on the Add button on the right. Input the “Dead Load” in the Title input box.

36. Select the newly created 1: Dead Load entry in the data area. Press the Add button.

37. Click on the Analysis/Print control tab item on the left and press the Add button.

38. Click on the Analyze->Run Analysis menu. Use the STAAD Analysis option and click

39. If the analysis completed successfully, you should look at the exaggerated deflected

40. You can look at the bending moment diagram for the bridge by clicking on the Beam-

41. You can look at the stress distribution diagram for the bridge by clicking on the Plate

3.0 Generate AASHTO 2002 Maximum Response

1. Maximum plate stresses, moment about the local x-axis of a plate (Mx), moment about

2. Maximum support reactions at the three supports which will be used to design pile cap

3. Maximum bending moment (Mz) in members 65, 145, 476, 555, 964, 1043, 1456, 1535,

1944, and 2023 used to design members as per the AASHTO code.

4. Maximum deflection at nodes 842 and 881 to check if the deflection of the girders is less

1. Click on Mode->Bridge Deck Preprocessor menu

2. The first step in STAAD.beava is to generate a deck and define a roadway. The second

3. To generate a deck and define a roadway, select the Plates Cursor and select all plates

4. Click on Deck->Define Roadway menu and click the New button. The next few steps

5. The Define Roadway dialog box contains three tabs. Namely, Straight, Curved, and

6. Click on the Custom tab and enter the following inputs:

7. The first lane has been created. To create the second lane click on the Add Lane to

8. The second lane has been created. To create the third lane click on the Add Lane to

9. The third lane has been created. To create the last lane click on the Add Lane to Right

10. Click on Loading->Influence Surface Generator. This will generate the influence

11. Click on the Loading->Influence Diagram from the menu. One of the maximum

12. Click on Vehicle->Database from the menu. This menu will display the vehicle

13. Click the Ok button on the Vehicle Database dialog box. Click on Loading->Run Load

14. Select the AASHTO ASD/LFD design code from the Design Code selection box. Select

15. Click on the AASHTO tab in the Load Generator Tab and select the HS 20-44 in the

16. Click on the Plate Center Stress tab in the Load Generator Tab. Input the parameters

17. The second AASHTO 2002 Maximum Response Criteria is the maximum support

18. The third AASHTO 2002 Maximum Response Criteria is the maximum bending moment

19. The Last AASHTO 2002 Maximum Response Criteria is the maximum deflection at

20. Press the Ok button. You will notice the following dialog box which will summarize the

21. The vehicle positions generating the maximum Response for each desired response can

22. Click on the response selection box located on the top right corner of your screen. You

23. These loads can be transferred to STAAD.pro as individual load cases for the slab,

24. In the General->Load control tab you will notice that all the AASHTO loadings have been

4.0 Bridge Design as Per AASHTO

1. Perform Analysis

2. Code Check

3. Select

4. Grouping

5. Perform Analysis

6. Code Check

1. Members 65, 145, 476, 555, 964, 1043, 1456, 1535, 1944, and 2023 are used to design

2. Create a group of members 65, 145, 476, 555, 964, 1043, 1456, 1535, 1944, and 2023

3. We will accept the default steel design parameters in STAAD.pro except for members

964 and 1043 have to have proper DFF, DJ1and DJ2 parameters assigned for the

4. Select beams 964 and 1043 in the graphics window and click the Define Parameters

14, and DFF 360 parameters have to be assigned to beam 964. The DJ1 14, DJ2 7, and

5. Select the Select->By Group Name command from the menu and select the beam

6. Click on Analyze -> Run Analysis command from the menu. Select the STAAD

7. Let us limit the depth of the girders to 2ft and 2.3ft for the selection. Create and assign

1456, 1535, 1944, and 2023 using the instructions in Step# 4 discussed above and must

8. Assign the Select and Ratio 0.9 command to members 65, 145, 476, 555, 964, 1043,

1456, 1535, 1944, and 2023. The Ratio 0.9 command must be placed before the Check

9. The last step in the design process is to check if this member selection is ok because of

10. Using the STAAD.pro editor, comment out the following lines as follows:

11. Perform the analysis as per the instructions in Step# 6 and you will notice that the beams

5.0 Conclusion