Frost-protected shallow foundation limitations - multi story commercial

[TroyD]

Are there limitations on the use of frost-protected shallow foundations based on occupancy type or number of stories? My client wants to build a 2 or 3 story building for indoor storage (125 psf Live), divided up into 10' x 10' storage units with 5' interior hallways. Approx. building dimensions are 250' x 76'. Material to be cold form steel studs and floor joists. The storage unit dividing walls will serve as bearing walls and interior shear walls. Exterior side walls will support roof only but also need to transfer lateral loads to the foundation. The building end walls will definitely be an issue for resisting lateral loads without foundation overturning/uplift for a building that height. If this were a single story unheated storage facility it would not be an issue, but I am skeptical due to the height. Builder is trying to save money. I don't think it is appropriate but I want to have an educated response.

I have a copy of ASCE 32-01 and have used it to design foundations for detached heated garages, etc. Project is located in Minnesota, 42" frost depth.

 

[KootK]

I know of no restriction with respect to building scale but, like you, it kinda rubs me the wrong way. A project this size must have a geotech, right? I'd be inclined to push the decision their way if possible. That way at least you're sharing the risk and adding credibility to you system selection if you go shallow. I hate the way that "No, because it gets my hackles up" sounds from a client management perspective, even if that is essentially engineering judgement at work.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[StrucDesignPE]

I recently completed a two-story house design in which the owner requested this type of foundation system. Like Koot, it also rubbed me the wrong way, especially given the soil types present on site (possibly expansive and prone to shrink-swell). It was also difficult to get the foundation to work due to the load eccentricity for the turndown style footing. In the end, we advised a geotech should be brought in. Haven't heard anything so far.