Concrete Frame Design Procedure

The following sequence describes a typical concrete frame design process for a new structure. Note that although the sequence of steps taken may vary, the basic process probably will be essentially the same.

Note:  It should be noted that two design processes are available in CSiBridge:  superstructure design (on the Design/Rating tab) and design of the individual elements comprising the structure (the Advanced > Frame Design commands). This topic addresses the second design process.

  1. Use the Advanced > Frame Design > Concrete > View/Revise Preferences command to choose the concrete frame design code and to review other concrete frame design preferences and revise them if necessary. Note that default values are provided for all concrete frame design preferences, so it is unnecessary to define any preferences; however, review the preferences, and if necessary change them, to ensure they are acceptable.  

  2. Create the building model. See Modeling Process for more information.

  3. Run the building analysis using the Analysis > Analyze > Run Analysis command. If desired, animate the deformed shapes and mode shapes in 3-D perspective by clicking the Start Animation button in the status bar at the bottom of the screen. Animate shell structures displaying stress contours with the corresponding deformed shapes in full 3-D perspective. While displaying mode shapes or deformed shapes, the vector being displayed can be instantaneously changed with the '+/-' buttons that will appear at the bottom of the screen. Use the Orb > Settings > Other Settings command to turn the sound associated with the animation off (uncheck the Sound check box) or on (check the Sound check box).

  4. Assign concrete frame overwrites, if needed, using the Advanced > Frame Design > Concrete > View/Revise Overwrites command. Note that frame objects must be selected before using this command. Also note that default values are provided for all concrete frame design overwrites, so it is unnecessary to define any overwrites; however, use this command to review the values, and if necessary change them. Note that the overwrites can be assigned before or after the analysis has been run.

  5. To use any design load combinations other than the defaults created by the program for the concrete frame design, click the Advanced > Frame Design > Concrete > Select Design Combo command. Note that design combos must already have been created by clicking the Design/Rating > Load Combinations > Expand arrow command.

  6. Click the Advanced >  Frame Design > Concrete > Start Design/Check of Structure command to run the concrete frame design.

  7. Review the concrete frame design results by doing one of the following:

If design results are not currently displayed (and the design has been run), click the Advanced > Frame Design > Concrete > Interactive Concrete Frame Design command and then right click a frame object to enter the interactive design mode for that object.

  1. Use the Orb > Print > Print Tables command to print concrete frame design data. If frame objects are selected before using this command, data is printed only for the selected objects.

  2. Use the Advanced > Frame Design > Concrete > Change Design Section command to change the design section properties for selected frame objects.

  3. Click the Advanced >  Frame Design > Concrete > Start Design/Check of Structure command to rerun the concrete frame design with the new section properties. Review the results using the procedures described in Item 7.

  4. Rerun the building analysis using the Analysis > Analyze > Run Analysis command. Note that the section properties used for the analysis are the last specified design section properties.

  5. Click the Advanced > Frame Design > Concrete > Start Design/Check of Structure command to rerun the concrete frame design with the new analysis results and new section properties. Review the results using the procedures described above.

  6. Again use the Advanced > Frame Design > Concrete > Change Design Section command to change the design section properties for selected frame objects, if necessary.

  7. Repeat the processes in steps 10, 11, 12 and 13 as many times as necessary.

  8. Rerun the building analysis using the Analysis > Analyze > Run Analysis command. Note that the section properties used for the analysis are the last specified design section properties.

  1. Click the Advanced > Frame Design > Concrete > Start Design/Check of Structure command to rerun the concrete frame design with the new section properties. Review the results using the procedures described in Item 7.

  2. Click the Advanced > Frame Design > Concrete > Verify Analysis vs Design Section command to verify that all of the final design sections are the same as the last used analysis sections.

  3. Use the Orb > Print > Print Tables command to print selected concrete frame design results, if desired. In addition, view time history displacements in real time video using the CSiBridge  video creation options or use the Custom Report Writer to generate a report, including analysis and design results, for the model.

Note:  It is important to note that design is an iterative process. The sections used in the original analysis are not typically the same as those obtained at the end of the design process. Always run the building analysis using the final frame section sizes and then run a design check using the forces obtained from that analysis. Use the Advanced >  Frame Design > Concrete > Verify Analysis vs Design Section command to verify that the design sections are the same as the analysis sections.