Beam-Column Design
Beam-Column Design
(OP)
I'm analyzing an existing roof of a warehouse. I have a beam that is supporting two bar joists. There is NO kicker from the bar joist bracing the bottom flange against twist, however, it appears that they considered the bar joist as bracing in the weak direction. Is this standard? The axial load on the original design drawing is 147k. The beam used is a W21x44. Its span is 20'. Fy=36ksi. The bar joist spacing is 6'-8". What are you guys feelings on this? There is no way the tensile bending moment will zero out the compression force in the bottom flange.






RE: Beam-Column Design
RE: Beam-Column Design
RE: Beam-Column Design
The W21 is a spandrel beam, 20' long, supporting 2 roof joists at 6'-8" o.c.. Is the exterior wall a shear wall?
I dont follow how you'd be getting axial force in your beam unless the beam is part of a frame.
RE: Beam-Column Design
RE: Beam-Column Design
Yes, the beam is part of the wind bracing. The bay is X-braced. The beam is also supporting the roof.
Can you name a text that covers columns braced one one flange only? I have never considered girts as bracing a column. However, the question of girts does bring up something else that I have often wondered. Do you consider the siding bracing the girt or is the unbraced length column line to column line? I go column line to column line since the siding is only on one side and would not help in suction.
RE: Beam-Column Design
RE: Beam-Column Design