Start of Tutorial
- The Project screen will be displayed. Enter the general information in the fields as shown in Figure 1. Select LRFD under Design Code, U.S. Units under Units, and Simple Span under Span Type.
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Select the Geometry tab as shown in Figure T5-4. Enter 32 in the Overall Width field, 1.5 in the Left and Right Curb Data fields, 101 in the Precast Length field, 100 in the Bearing to Bearing field, and 101 in the Release Span field.
Note that the number of lanes is automatically calculated as 2 based on the default lane width of 12. Also, since Precast/Prestressed Girder only designs symmetric beams, the distance from end of precast to centerline of bearing on the left side is internally set to be the same as that on the right hand side.
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Input the first beam. Under Beam Type/Location, select Adjacent Box Beam from the Beam Type list, AB_B-IV 48 from the Beam ID list, and enter 2 in the Dist. From Last Beam field.
Note that the distance for the first beam is the distance between centerline of the beam to the left edge of the bridge.
- For the second beam, select AB_B-IV 48 from the Beam ID list and enter 4 in the Dist From Last Beam field. (NOTE: This is the same as Beam #1.) Repeat the above procedure to add the remaining beams, as shown in Figure 2 Once completed, there should be a total of 8 beams.
- Select the Post-Tensioned check box on the Geometry tab. This option will calculate the distribution factors for the case of beams with shear keys sufficiently connected so as to act as a unit instead of the options where beams with shear keys connected only enough to prevent relative vertical displacement at the interface. Notice in this tutorial, a deck thickness is not specified. As a result, the program calculated the distribution factor differently than the case where there is a cast-in-place concrete overlay (i.e., cross-section (f) as per LRFD Table 4.6.2.2.1-1).
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Click the Materials tab to activate the Materials screen. Input the information, as shown in Figure 3 for concrete, rebar, and prestressing tendon
Note that the elasticity of concrete is automatically calculated by the program based on the strength and unit weight input.
- Click the Loads tab. For this tutorial, the different types of loads used are the weight of barriers (2 *0.300 klf = 0.6 klf) as Dead Load on Composite DC and 3-inch bituminous wearing surface as Area Load (3/12 * 0.140 kcf = 0.035 ksf) spread over a distance of 29 ft on the bridge deck as Dead Load on Wearing Surface DW. The procedure for adding loads are outlined in Step 8.
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To enter the first permanent load, select Composite DC from the Components list, Line Load from the Types list, and enter 0.6 in the Mag. klf field. Click Add and it will appear in the list on the screen, as shown in Figure 4
For the second permanent load, select Composite DW from the Components list, Area Load from the Types list, and enter 0.035 in the Mag. ksf field and 29 in the Width field. Click Add and it will appear in the list on the screen.
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Model the diaphragm loads at the beam quarter points (25, 50, and 75 ft) on each beam. For this tutorial, since you are only designing Beam #2, you only have to model the loads for Beam #2. The load magnitude of the diaphragm is 0.81 kips for each of the three points.
For the first point, select 2 from the Beams list and enter 25 in the Loc. ft field and 0.81 in the Load, kips field. Click Add and it will appear in the list under Diaphragm, as shown in Figure 4.
Next, enter 50 in the Loc. ft field and click Add. It will appear in the list on the screen. Then, for the third point, enter 75 in the Loc. ft field and click Add. Once all three points have been added, the screen will resemble Figure 4. Note the location of the diaphragm loads are measured from the centerline of bearing.
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You will not be making any changes to the Live Load section on the Loads screen. For this tutorial, you will be using the default live loads (Design Lane, Design Tandem, and Design Truck) for a simple-span beam.
Note that Precast/Prestressed Girder comes with specific built-in live loads depending on the design code selected. For LRFD, the default live load is default.cs3. To verify both the library and path, select Setup from the Libraries menu.
- You will not be making any changes to the Live Load section on the Loads screen. For this tutorial, you will be using the default live loads (Design Lane, Design Tandem, and Design Truck) for a simple-span beam. Note that Precast/Prestressed Girder comes with specific built-in live loads depending on the design code selected. For LRFD, the default live load is default.cs3. To verify both the library and path, select Setup from the Libraries menu.
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Click the Analysis tab to activate the Analysis screen. Click Analysis Factors to activate the Analysis Factors screen and select the Load Factors tab, as shown in Figure 5.
Note that the Strength II Limit State check box is not selected, because for this tutorial, we are not interested in results for this limit state. Click OK to close this screen and return to the Analysis screen.
- Save the project. Select Save from the File menu. The Save As screen will display. Enter a name in the File Name field (e.g., MyTutor5) and click Save. The default extension is *.csl.
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Click Run Analysis on the Analysis screen. This will automatically launch the solver engine, showing you a \progress bar while this module is running. When the analysis is done, the results will appear on the screen, as shown in Figure 6.
By selecting the Type, Span, Beam, and Limit State lists, you can view individual load case results or final envelope results for the different beams. To print the analysis results, click Print.
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After reviewing the analysis results, click the Beam tab to activate the Beam screen, as shown in Figure 7. Select 2 from the Beam list (or the cross-section of the beam displayed at the top of the screen).
Once selected, it will turn red, indicating it is the selected beam. For this tutorial, you will not be modifying any of the data at the beam level for this particular beam.
- Click Strand Pattern to activate the Strand Pattern screen. Click Auto Design. The program will automatically design a strand pattern with 26 straight strands. However, please input 27 strands as shown in Figure 8.
- Click Strand Pattern to activate the Strand Pattern screen. Click Auto Design. The program will automatically design a strand pattern with 26 straight strands. However, please input 27 strands as shown in Figure 8.
- The Design Status screen is shown automatically for the program-generated strand pattern. You can also click Design Status to activate the Design Status screen. Notice that all the stresses are less than the limiting stresses, as shown in Figure 9.
- Click the Show menu and select Results, as shown in Figure 9. Here, you will see the final results for Beam 2 arranged per limit state and engineering function. From the Type list, select the type of results you want to see for the specific beam (e.g., shear and moment, detensioning, etc.). Click the X in the top right hand corner to close this screen and return to the Beam tab screen.
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Precast/Prestressed Girder provides many diagrams for your project. Select Diagrams from the Show menu. The Diagram screen will appear, as shown in Figure 11.
Use the lists to view the various diagrams of your project. Experiment with the various options available to become more familiar with their functions. Click the X in the top right corner of the screen to close the screen.
