SCBF - Intersection of Bracing
SCBF - Intersection of Bracing
(OP)
Working on a SCBF and looking for a little guidance with the intersection of the bracing. Working on an X-braced configuration, and at the intersection of the braces one will be discontinuous. Trying to work out the details of the intersection, one is the thru-plate going the continuous brace, should it be welded to the brace? I was concerned of a weld transmitting load through the walls of the brace and not through the plate. Also, should the plates and welds be designed for the loads indicated in F2.6C of the provisions? In the provisions it seems like they are talking specifically about brace-to-column/beam connections.






RE: SCBF - Intersection of Bracing
http://www.pacosteel.com/wp-content/uploads/2016/0...
However, if it can't be avoided the prevailing detail appears to be weld the knife plate to the opposite brace tube.
https://www.researchgate.net/profile/Dawn_Lehman/p...
https://i.pinimg.com/originals/48/69/44/48694491e6...
Have not run through such a brace connection design, so I'd have to dig into the code to see what's required. I imagine the post-buckled load case is going to be a huge driver of the design forces on this connection. Also, I would suspect that overstrength is required as failure of this weld would cause a change in the assumed load path and the buckling capacity of the braces.
Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries
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RE: SCBF - Intersection of Bracing
RE: SCBF - Intersection of Bracing
1. It eliminates the slots in both the continuous and discontinuous braces.
2. It eliminates the need to reinforce the braces for net section fracture since the slots are eliminated.
3. It allows you to maintain flexural continuity of the discontinuous brace across the joint, which improves the ability of tension brace to keep the compression brace from buckling out-of-plane. When designing the brace, use half the brace length with K=1.0 for initial sizing and K=0.7 for upper bound compression strength. The shorter unbraced length allows you to use smaller, more compact braces that better dissipate energy in an earthquake.