I think you're right - It only makes up ~10% of the total roof area and is less than 18'-0 above the low roof DBE. If that popup is a "penthouse", then we should be able to use the lower roofs for the structural height. That would put us below 35'-0 and we'd be able to use OCBFs, which would...
Thanks for the reply!
You're correct, the columns extending to the high roof do go all the way down to the base. On 2-sides, the BRB's extend up to through the high roof, so we are good in that direction. My concern is in the other direction, where we can't have full height bracing. See below...
I'm hoping to simplify a high seismic design that I'm working on. It's a 2-story office building with low roofs on the east and west side. Each of these roofs are ~30'-0 tall and supported by BRB's in all 4 directions and have a 2nd floor connecting the 2 portions at ~15'-0. At the center of...