Steel beams Bearing on CMU Stair wall. 1

[mijowe]

I have a load bearing 8" CMU stair shaft and the wall has a 2-hour rating. For steel beams sitting on the wall I typically just use a standard beam with bearing plate. I have been asked to keep my steel, bearing plate included, 4" from the inside face of the wall. 4" being the minimum masonry thickness for a 2-hour rating. IBC Section 714 does a decent job of setting restrictions, but only in the context of MEP / Electrical. Is there specific IBC guidance on sitting non-combustible structural steel on a wall and not altering the rating?

 

[JAE]

713.8 (IBC 2015)?

"Penetrations in a shaft enclosure shall be protected in accordance with 714 as required for fire barriers. Structural elements, such as beams or joists, where protected in accordance with Section 714 shall be permitted in shaft enclosures."

All of 714 allows firestopping in and around all kinds of wall penetrations. Seems like you could simply fill the beam pocket with firestopping, or grout, and meet the code that way.
The firestopping is for both limiting fire spread and, usually more applicable, limiting smoke access through the wall. You already have the smoke stopped with the remaining face shell. So the issue is whether that one beam pocket is susceptible to fire spreading through the "hole". For ductwork - they let the duct come completely through with firestopping around it. Seems to me that a non-combustible steel beam in a fully grouted pocket is significantly more fire resistant than a duct with firestopping.





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[Bagman2524]

Is issue here ensuring that the steel supporting the stair is inside the 2-hour rating, so that it is not compromised during a fire? or that the 2 hour fire rating surrounding the cell opening is maintained. Either way JAE's idea of firestopping inside the wall would achieve both.

All I know is P/A and Mc/I