Working on a steel project in which we're using CoreBrace BRBFs for a portion of our lateral system. We've gone through the first part of our lateral analysis and have received a table of values (including overstrength parameters) back from CoreBrace. Using these overstrength parameters, we've been able to update the RAM SS model to accurately model the forces that are seen by the buckling restrained braces. Similarly, the seismic provisions design allows us to fully design the columns in the frames for the expected forces that will be delivered by the BRBs as well. All is well in the world.
One question I do have is if RAM SS will allow for design of the column baseplates at the bottom of the BRBF columns. Knowing that the gussets themselves will be in CoreBrace's court, it still seems like it would be useful if RAM SS would allow us to design the baseplate and anchorage "in house" rather than bookkeeping to transfer these loads to another program. It seems like we already have the design tension and could pull the design shear (from the expected brace force). That said, is there a way to do this design in the RAM SS connection module?
bump
Seth - one clarification. When you view the "seismic provisions member code check" for a BRB column, the program shows the value in tension from the Overstrength combination as well as the required tension strength (based on adjusted brace strength). My assumption for this value is the following for a diagonal brace configuration:
This would align with the AISC seismic provision so I would assume this is the case but figured I'd confirm as it doesn't give a breakdown of the expected strength calculations.
I think I would use the Stand alone program and put the expected forces in as a brace axial force for some load combination explicitly, and then design the plate using that combination (without other seismic provisions). I'll pass along a request to allow for more automation (Backlog item 568048 BRB Gusset Base Plate Design).
Thanks Seth. I was thinking along these same lines. I guess my question is this - if I end up using an equivalent section (say an HSS or a square bar), is there any way to maintain the use of the "expected forces" from those braces for the design in RAM SS to keep them "linked"? If not, it seems like you're basically just going to run the RAM Frame analysis, pull out your design forces, and then design separately in RAM connection. This is not the end of the world, but was hoping to hold onto a little efficiency by maintaining those design forces if possible.