AISC 341 and two-story x bracing
AISC 341 and two-story x bracing
(OP)
In the AISC 341 provisions for OCBF bracing, a slenderness limit of 4sqrt(E/Fy) is defined for V bracing. When implementing two-story X bracing, are these braces considered as V braces for satisfying this slenderness limit?






RE: AISC 341 and two-story x bracing
RE: AISC 341 and two-story x bracing
RE: AISC 341 and two-story x bracing
AISC 341-2005, section C13.1 figure C-I-13.3 I think you will see your type of configuration listed as an X braced frame. Though the text of the commentary suggests that the behavior should be consistent with a V braced system
To me "behavior consistent with a V braced system" suggests that you need to design it to the V braced provisions inluding that KL/r restriction.
RE: AISC 341 and two-story x bracing
RE: AISC 341 and two-story x bracing
True. But consider how a two-story brace is formed, by mirroring a chevron brace about a beam so that it forms an "X" over two-stories. In an X-braced frame, where the "X" is within each story, the effective length can be cut in half because you could suppose that the braces are supported at their midpoint, assuming that they are connected together. In a two-story configuration, you don't have the ability to do that, so slenderness becomes a concern because you don't want your braces to buckle before they yield. I would say the provision for cheverons would still apply because of this.
RE: AISC 341 and two-story x bracing
RE: AISC 341 and two-story x bracing