Loads in stud wall bridging for stacked multi-level walls 4

[Structintern3]

Hey Guys,

I've been asked to find the load in the stud bridging for multilevel stacked CFS bearing walls in a residential apartment building (and also tie it back into the diaphragm). I'm a little confused on what they're looking for on this. My understanding is bridging is just bracing. Could anyone point me in the right direction or share some of your thoughts on how you'd go about doing this?

Thank you!

 

[WesternJeb]

Are you in design phase or construction/remodeling phase? If it is existing, are they looking into cutting said bridging? The reason why they're asking could be extremely important for this.

The bridging is used to reduce the unbraced length of wall studs; you can't remove it and throw it into the diaphragm as this would increase the unbraced length of the studs and compromise integrity. If this is new construction then you will need to increase your stud size if you take the bridging out.

 

[phamENG]

I got a similar question on my first CFS project. My boss had me 'delegate' the CFS design, and it wound up on the desk of a guy who'd been doing it for decades. Fortunately, he was incredibly nice and spent 3 hours on the phone with me showing me all the things I screwed up and how to do it better. This was one of those things.

Rather than spend three hours explaining, it, though, I'll just point you to this nice Structure article that sums it up pretty nicely. It's a few years old so the code references may not be current, but it should set you in the right direction.

Mechanical Bridging Anchorage of Axially Loaded Cold-Formed Steel Studs

 

[Structintern3]

@westernjeb So this is design phase. I'm with you that when I think of bridging I just think of "reducing studs unbraced length" but I've been asked to figure out the loads in the bridging. Not really sure what that means there.

 

[Celt83]

See this thread: Link

The CF studs are all essentially columns which require a certain level of bracing by the bridging to prevent buckling, see AISI S240 and S100. The bridging itself needs a continuous load path into the lateral force resisting systems of the building, a common mistake is having a horizontal row of bridging elevated in a stud wall with no actual load path for the bracing force to enter the diaphragm either diagonal bridging or built-up stud post.

 

[Structintern3]

@phameng thank you! I'll look into that

 

[Structintern3]

@celt83 great explanation that makes sense, thank you!