BS 5950 Lambda Critical At Control Points

Process > Results > BS 5950 Lambda Critical > At Control Points is only available to rigid diaphragm models.

Process > Results > BS 5950 Lambda Critical > At Control Points allows you to select and store up to four points at which Lambda Critical will be automatically calculated. This provides a powerful tool for comparing the effects of differing load cases (Analysis Mode) or load combinations (Post-Processing Mode) and designs.

Selecting Process > Results > Drift > At Control Points opens the Lambda Critical at Control Points dialog. Control points are set from within this dialog box.

Important: In Analysis mode the Lambda Critical points are produced for hard coded load combinations. These load combinations reflect the appropriate load factors for the notional loads from all the typical (code prescribed) load combinations. These combinations can be used to assess the sway state (sway/non-sway) of the frames, which can then be assigned to the frames in the Steel - Post Processor mode. In Load Combination mode only the notional load case terms in each load combination are evaluated to calculate lambda critical at the selected points.

To Add a Control Point:

Enter the X and Y values directly into the corresponding column of the spreadsheet provided.

To Change a Control Point:

Click on the spreadsheet entry of the coordinate you wish to change. Modify the values as desired within the spreadsheet.

To Delete a Control Point:

Click on the spreadsheet entry of the point you wish to delete.
Click the Delete button.

To view the report for all Control Points, Click the View Results button. The report states the deflection, interstory drift and Lambda Critical for each level for each analyzed load case.

To get a print out of the report - Click the Print Results button. Clicking the OK button will save the control points or changes made to the control points and return you to RAM Frame. Clicking Cancel will abort changes and return you to RAM Frame.

Note: The Lambda Critical values will be calculated (Lambda critical = 1.0/ (story drift ×200)) for all analyzed load cases, but they are only valid for Notional load cases.