SJI Bottom Chord Ceiling Extensions (SJI COSP 2.6)

[RangeRock]

Anyone have some good photos of bottom-chord ceiling extensions as specified per SJI COSP 15 they'd be willing to share?

Curious to see what types of ceiling systems require these and the overall concept-in-practice. Understand the structural intent... but always good to see in-field conditions. Thanks!

 

[Once20036]

Could you share a snip of the language you`re looking at? SJI COSP 2.6 or SJI COSP 15?
I may have some pics, but I don't have those provisions at my finger tips.

 

[lexpatrie]

Just gonna say, bottom chord extensions for ceilings are usually concealed by the ceiling. So most of us don't get to see them.

That said, typically you'd have one of the angles extended, not both. I don't think I've seen a loading diagram for anything like this, it's just a callout for a bottom chord extension "for ceiling support". So they aren't engineered, so to speak, but there's no documented history of failure that I'm aware of either. If that's of any help.

 

[RangeRock]

@Once20036, please see attached reference as requested.

 

[lexpatrie]

Interesting, it says they are only for ceilings directly attached to the joists. It does state they should be designed (in that case) for the "specified load" so the design professional is supposed to provide a weight. They are not typically furnished for suspended ceilings, so they are probably not normally furnished. (This is pretty much an architectural issue that they're supposed to be circling up and commenting on during shop drawing review.)