Cantilevered Canopy Connection Detail

[KHoff]

I am working on a mixed-use building that has underground parking, retail space on the first floor, and two stories of lofts above. Precast framing is used for the garage and retail, and the lofts are wood framed. The front of the retail level will have storefront with cantilevered canopies along the majority of the length of the building. The attached image shows what the client would prefer do for the attachment of the canopies.

I do not like bolting through the brick veneer for several reasons. I typically try to avoid using brick veneer to resist structural loads. It seems like a bad idea to have the bolts cantilever past the brick veneer, I doubt the canopy manufacturer's standard connection would account for any bending stress in the bolts. Also, if the bolts were over tightened it seems that could cause issues for the veneer anchors. In my opinion it is a better detail to bolt the canopy directly to the steel structure supporting it. This could mean the steel tube is shifted left such that the face of the tube is flush with the face of brick above. Or perhaps there are stub tubes that penetrate the brick veneer at canopy connection points.

I would like to know if other engineers agree with my concerns, or perhaps I'm being overly critical of this connection detail. Any input would be appreciated.

 

[BAretired]

I agree fully and would never use that detail. You must be careful, however to avoid a thermal bridge, particularly if the building will be exposed to very cold temperatures.



BA

 

[DETstru]

I definitely wouldn't bolt through the brick like that. See the attached detail, that's what I would propose.

I think it's going to be really tough to get that embed to work. How much brick is sitting on that ledge? Any opportunity for a kicker back into the building?

 

[KHoff]

There will be additional steel framing to help support the canopies, not just the tube steel hangers. The tube hanger detail is for support of brick veneer, the client just used it to sketch his preferred method for connecting the canopy.

 

[Teguci]

Assuming the moment can be carried by the threaded rods, the brick will still need to take the vertical force from the canopy and carry it into the brick ledge. Why would you do that? Replace a brick with a structural bracket at the necessary spacing and cover the area with an escutcheon plate. You should even be able to hide the bolted connection behind the plate and just have a nice clean canti- beam sticking out.

 

[KHoff]

Quick update... The canopy manufacturer has provided a detail (see attached) that they have used in the past to connect their canopies through EIFS (2 1/2" thick). However, our brick veneer, air gap, insulation and sheathing add up to 6 3/8". Also, I am unconvinced that these crush sleeves would provide bending resistance to avoid loading the brick veneer, which is still a concern.

 

[mike20793]

I would/do use a small piece of tube with a plate on the end welded to your main support tube and connect the canopy to that. The plate with give them something to brick behind and cover everything up and the main tube can handle the torsion easily. I've also seen it done with z-plates coming off the tube.

 

[BAretired]

Are the diagonal pipe hangers suggested by the canopy manufacturer acceptable to the architect? If so, the problem is a little easier to resolve than the one shown in the first sketch although there are still some issues.

BA