I understand from the Bentley Wiki post about the Effective Length Method that to help validate the analysis method, one should look at the maximum B2 factor provided in the AISC 360 Direct Analysis Validation Report. This report, however, only provides the maximum factor throughout the building, and not each individual level.
In my case, there are some intermediate levels (Lobby Level between Level 1 and Ground Level, elevator support framing and roof of an existing portion, etc.) that do not have any lateral members. These intermediate levels are causing the maximum B2 factor in the report to be greater than 1.5, however do not contribute to the lateral stability of the building and feel they should not be looked at when trying to validate the Effective Length Method.
Without making a separate model and deleting these levels to check the validity of using the Effective Length Method, is there any way in RAM to view the B2 factors for every level in the building? Or, is there a way to ignore these intermediate levels in the analysis to see the true performance of the system?
It's tricky to override this in Ram Frame. Check this for some ideas: https://communities.bentley.com/products/ram-staad/w/structural_analysis_and_design__wiki/19014/ram-frame-criteria-b1-b2
Thanks for the quick response, Seth. Unfortunately it did not answer my question.
I am not trying to override the B2 factors, simply true to view what the calculated B2 factors are for each level instead of just the maximum B2 that is displayed in the AISC 360 Direct Analysis Validation Report. Is there a way to do this?
Seth Guthrie Any thoughts on the response would be appreciated. Thank in advance!
You can go through the design report for each member to spot check the B2 factor used, but that's the only way I know of.
Thank you very much, Seth!
Seth Guthrie I'm having trouble finding any member report that states any type of B2 factor. The Member Code Check report lists B1x, B1y, and Cbx factors. However I am not seeing B2 anywhere. Can you please point me in the right direction for which report you're referring to to spot check member B2 factors?
B2 should be shown on the same report. Are you in Ram Frame - Steel - Standard provisions, using some US code and verison 17.02.01.23? Check that you have B2 factors turned on under Criteria - B1 and B2. The worst B2 factor is also reported in the AISC 360 Direct Analysis Validation Report.