Freezer Building X-Brace
Freezer Building X-Brace
(OP)
I am working on a freezer building where the columns are isolated from the foundation using a 6" insulating block. At lateral brace locations, in my case an x-brace, how is shear transferred through the block and into the foundation? If I consider the anchor rods in bending, the moment arm is too long and it leads to an excessive size and number of rods. Is there an alternate insulating pad that can be used that is thinner and yet provides protection for the footing?






RE: Freezer Building X-Brace
RE: Freezer Building X-Brace
Dik
RE: Freezer Building X-Brace
It’s been a very long time since I’ve been involved in the design of a freezer warehouse, so these are just some recollections of an older fellow, and maybe not the latest design/insulation details. Dik is right, you do usually need some heating system below the floor insulation, or you get some nasty freezing problems. Literally, an air flow tile system under the floor. Can you use a few more panels of x-bracing, so as to lower the shear at each column base, and stiffen the building frame? Can you weld a 3-4" sq. tube to the bottom of the base plate which extends down into the pier through the insulation block, just as the A.B’s. do? You have to pay some special attention to the lateral flexibility of these steel frame buildings, as this relates to the relative rigidity of the exterior insulation panels, or the panels will try to take the lateral loads. They act a vertical shear panels, and the joints btwn. the panels and at corners get abused, and don’t hold up. The panels can take the normal loads into the steel frame, but they should not be forced to rack w.r.t. each other. I’ve seen globs of ice on the exterior of these panel joints which you could chop off with an ax. In that case I was working for the panel manufacturer who was being blamed for the problem. You have to control the lateral frame deflection and connection details to manage this difference in stiffness. Most good insulated panel manufacturers have established details to manage this, listen to them.
RE: Freezer Building X-Brace
RE: Freezer Building X-Brace
Ishvaaag: I am not completely following your suggestion. I don't see how I get around the fact that I still have shear being applied to anchor rods 6" above where they project from the foundation.
dhengr: I am pretty much locked in to where the braces are.
The GC provided me with a detail they used on a prior job. In place of the block they used a 1" thick elastomeric bearing pad. I like that because I can get the anchors to work no problem. Is the 1" pad + the underslab heating enough to protect the cold from transferring into the footing? I am going to keep digging to find that answer.