AISC 360-10 B3.6 - Restraint Against Rotation Clause
AISC 360-10 B3.6 - Restraint Against Rotation Clause
(OP)
I was recently asked to review the design of a new 10'x12' rollup door addition in response to some questions from the owner's reviewer. The building is an existing 1970s PEMB in the middle of Indiana. The new frame for the door was designed with 8" deep MC vertical channels and a matching sized door header similar to other roll up door frames in the building. The top of the vertical channel was connected to a C4 wind girt spanning 15 ft between main building columns. The connection is a L4x4 2" long welded to the vertical channel and 2 bolts in standard holes on the girt. The owners reviewer has question the connection, specifically citing 360-10 B3.6 "At points of support, beams, girders and trusses shall be restrained against rotation about their longitudinal axis unless it can be shown by analysis that the restraint is not required".
But when reviewing the clause, the only quantitative way I could think to prove the connection is to use 1/2 the T-dimension of the MC8 from the 14th Ed. 10-49 as the recommendation for stability of shear end plate connections. Is there another section to consider? Any constructive comments would be appreciated.
But when reviewing the clause, the only quantitative way I could think to prove the connection is to use 1/2 the T-dimension of the MC8 from the 14th Ed. 10-49 as the recommendation for stability of shear end plate connections. Is there another section to consider? Any constructive comments would be appreciated.






RE: AISC 360-10 B3.6 - Restraint Against Rotation Clause
I think that your reviewer is probably right about the connection. It will be rather poor torsionally. I suspect that the argument to make is that the vertical C8 is braced by the horizontal C8 tying into it a bit lower. Using this strategy, you would treat uppermost portion of the vertical C8 as a short cantilever.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.