Has anyone used styrofoam blocks at column locations before (See here)? I'm curious to know how you've treated this at braced frame locations (the horizontal component)?
I would imagine you would have to design the anchor bolts to take the shear and flexure based on the eccentricity from the foundation pier to the bottom of the baseplate. Whatever the case I'd contact the manufacturer of the styrofoam and see what they say.
I think these would be used for freezer buildings where you need to prevent the soil from freezing below the slab. The block is a thermal break between the sub-zero temperatures of the structure and the temperature of the soil. At brace locations you will probably end up with some large bolts as you need to account for bending of the bolts..... don't know how this will effect the thermal break though....
Yes, this would be for a freezer application. I'm wondering if they would allow some sort of gusset plate. I imagine trying to take it out in the bolts might be difficult.
We have always used oak blocks. One of my clients (a refrigerated warehouse company) tried these out and didn't seem to like them so we went back the oak blocks.
A few years ago when my employer went out of business I went for an interview at a DB construction company that works mostly in the food industry. They had lots of buildings that required large freezers. I asked them if they used oak blocks at the base of their columns and they said no..... they use a different material. Must have been using these types of blocks. When I asked about oak they looked at me like I was an idiot. I thought I was the only one that used this detail.
I've used these for a refrigeration facility in the past. I had the very same concern. What we did was count only on friction between the base plate, bearing pad, and concrete. Obviously, you need to engage enough DL to make a go of it which was a huge hassle for me. Other options to consider:
1) Prestress your anchor bolts to gain a little more friction. Reliability is an issue with this.
2) If your detailing permits it, deal with the shear in the slab on grade. The brochure seems to suggest this.
I expect that utilizing bolt bending would be tough. Would one consider the bolts to be in single or double curvature in this scenario? A gusset plate would be great but it probably undoes the wonderful thermal benefits that you're gunning for in the first place.
Whenever I encounter this thermal break business, there always seems to wind up being some bridging. The name of the game is minimizing that bridging rather than eliminating it altogether. With that in mind, I should think that it would be okay to forego the isolation at the braced columns. If 90% of your columns are thermally isolated, that's got to get you most of your energy loss benefit, right? 80/20 principle and such? I didn't do this but, in retrospect, I wish that I'd tried.
The greatest trick that bond stress ever pulled was convincing the world it didn't exist.
