Standard details for steel joist connection 1

[prblmfxr]

Where can I find standard details for the following roof-to-wall connections:
1. Steel bar joist bearing on CMU wall. Question: Should the embedded steel bearing plate in the masonry be flush with the top of CMU, or should the top of plate be slightly above the CMU so that the joist bearing is completely on the steel, not on the CMU?

2. Steel roof deck diaphragm connection to non-loadbearing steel stud wall sheathed with OSB. The steel joists run parallel to this wall and I need to connect the diaphragm to this wall, as this wall is one of the main shear walls of the building. One twist: the steel joists are sloping at 1/2" per ft., while the top of wall is held horizontal.

 

[jheidt2543]

Here are my thoughts:

1. The embedded joist bearing plate details I've seen have all been set flush with the top of the block. If you watch a mason setting the plates in wet mortar or concrete fill, how is he going to hold it up so each is at the same elevation? You do raise good point however, if the joist shoe should rotate under load and bear on the edge of the block, it could crack it. I have never seen it happen though and the same question could be asked for beam bearing plates and I would give the same answer.

2. The simplest detail would be to run a continuous angle along the stud wall at the proper elevation, even if it has to be pitched to match the roof line. However, if the wall is non-load bearing(I assume you mean vertical load), how can it be a shear wall?

 

[Engrman]

Practice around here is to usually use a 3/8" bearing plate (unles thicker by calcuations) with bottom flush with top of cmu. In this scenario the joist will never bear on the cmu.

 

[Ron]

In general, the embed plates are set in tie beams cast above the masonry. While they can be flush with the top of the masonry, the masonry would be, at the least, a U-block or lintel block, filled with concrete at this elevation for bearing and for a tensile tie (uplift). My preference is not to use "U-block" or lintel block for joist bearing purposes. I prefer a cast-in-place tie beam with the embed plates set flush with the top surface of the tie beam.

I would also use a continuous angle, parallel to the top chord of the joist, on the stud wall. Are you sure you want that wall to accept diaphragm loading in two directions? If the joists are sloped, you will have a vertical component of live loads and wind loads transferred to the stud wall when connected. If you are in a high wind area or high snow area, this can be significant.