BAG Generator - Control Data Form

Begin developing the bridge model using the options on this form.

TIP:  After defining the control data, click the Define menu > Geometry command or the Define Geometry button  to proceed to  the next step in building the bridge model.

• Bridge Title edit box.  Enter a maximum of 24 alphanumeric characters to identify the problem. The input is used as the title for the model.

• Main Control Data options. Use these options to set the parameters used in the analysis:

• • Number of Modes to Consider edit box.  Enter the number if modes to be included in the response-spectrum analysis computation. If this field is left blank, the program defaults to 3 times the number of spans, or 12, whichever is greater.

  • Number of Extra Joints added per Span edit box.  Enter the number of joints to be added per span.

  • Number of Extra Joints added per Column edit box.  Enter the number of joints to be added per column.

  • Add Small Elements At Abutments drop-down list. Select 'Yes' to add one extra element of 1 ft length at Abutment1 and Abutment2.

  • Add Small Elements At Hinges drop-down list. Select 'Yes' to add one extra element of 0.5 ft length on each side of every hinge.

  • Apply Standard Bridge Layout Rotation drop-down list. A ‘Yes’ or blank in this field causes the structure to be rotated in a horizontal plane so that the centerline of the structure or the chord between the abutments coincides with the Global X axis.

  • Design Temperature Range Degrees edit box.  The design temperature used here is for concrete structures only. For steel structures, the user may modify the range by the difference between two materials (see BDS Article 3.16). The default value is 35 degrees.

  • Units display box. Displays the type of units, English or Metric (ft-kip or m-kN). To change the type of units, close the BAG-Grid Analysis Generator form by clicking the X in the upper right-hand corner of the form. Then repeat Steps 1 through 5 above.

• Earthquake Data Use these options to set the parameters for seismic load calculations:

• • Spectrum Modification Factor edit box. All values of the elastic response spectra will be multiplied by this factor. If this is left blank, a default value of 1.0 will be assumed. Select one of the following two options for Earthquake Load Data

1. • • ATC 32 Response Spectrum Curve

     • • Peak Rock Acceleration drop-down list. Specify the peak rock acceleration, given in tenths of the acceleration of gravity, ranging from 1 to 7 (i.e., 0.1 to 0.7)

       • Soil Profile Type drop-down list.  Indicates the soil profile type. Only curve designations B through E are acceptable.

       • Earthquake Magnitude drop-down list. Indicates the earthquake magnitude. The choices are 6.5 +/- .25,  7.25 +/- .25,  8.0 +/- .25.

     • Site Specific Response Spectrum option. Specify the site specific response spectrum file name. Use the Browse button to locate the file.

See Also

BAG - Bridge Analysis Generator

BAG Geometry Data

BAG Define Spans

BAG Define Bents

BAG Pier/Column Type