Steel Collector to CMU Bond Beam

[EngStuff]

Hi all,

I was wondering if we have a steel W-shape collector(edge beam of roof) that transfers to a CMU bond beam corner. How would we design/detail it? My thought is the typical steel plate with studs into a bond beam and weld the collector onto the plate. So if it's 10kips horizontal load, we just need to make sure that bond beam connection can handle that load.
This is at a roof diaphragm and the masonry wall is acting as a shear wall. Also, This is a SDC B building. Anything else I should look into when designing these type of connection.

EDIT: (I didn't show the rebars in the bond beam.) should I hook them?

THANKS!

 

[hotmailbox]

Few different ways I'd do it:
1. End plate with horizontal bars welded to the back
2. Horizontal bars welded to the bottom of bearing plate.

 

[EngStuff]

That simplifies everything for me. haha

another question for a different job that will be placed on my desk in the near future. What if the collector was a foot away from the corner wall? what would you prefer to do? connect it to the roof joist on the CMU side and make sure that joist can transfer the loads out to the diaphragm or design a sub diaphragm at that location? Or would you like to try bracing it onto the shear wall since it's only about a foot away?

Thanks.

 

[GC_Hopi]

Look into TMS 402 and ASCE 7. If these are seismic loads you need to amplify them and there are other detailing requirements based on the SDC. One option for a robust system is to use welded dba to the plate then use a pilaster with ties and hook the horizontal reinforcement at the pilaster. Once you start running numbers you may get a better feel for sizes, edge distances, etc. Also here is an article that is related and the references at the end of the article are some good resources. Link

 

[EngStuff]

Thank you very much!

 

[KootK]

One thing that I'd be wary of is accidentally creating a gravity load moment resisting connection at the end of tbeam. If that happens, odds are that you'll crack the whole thing apart under gravity load long before your lateral loads materialize. I don't imagine that your axial load here is enormous so you could probably set the beam up on a bearing bar that would be a bit more rotation friendly while still being able to transfer the axial load. You still kind of wind up with some prying on the welds though.

 

[KootK]

another question for a different job that will be placed on my desk in the near future. What if the collector was a foot away from the corner wall? what would you prefer to do? connect it to the roof joist on the CMU side and make sure that joist can transfer the loads out to the diaphragm or design a sub diaphragm at that location? Or would you like to try bracing it onto the shear wall since it's only about a foot away?

I could get behind either detail and would probably need a lot more information in order to decide.

I like the sub diaphragm idea as that might be as simple as a tension connector plate connecting the beam top flange to the joist top chord. But, then, will you really have a joist 1' from the wall? That seems unlikely. If not, a solution might be to bridge the joist and shear wall with a channel on the flat etc.

You certainly wouldn't be the first engineer to just connect the beam to the supporting wall for axial and assume that the lateral makes it's way over to the shear wall over that 1' distance "somehow". It's a bit of a tricky thing to prove rigorously though.

Would your "brace it to the wall" scheme be something like I've shown below? It would be nice to be able to do that on the collector side of the CMU but I imagine that whatever's driving the 1' offset would also preclude that.