What is the best type of foundation for a steel building (30′x40′) on clay, in an area that gets 45" rainfall annually? (East Texas, red clay) Please note, this steel building probably won’t weigh as much as a wood house. Steelmaster arch style.
Concrete slab?
Driven piles (if so, which kind)?
Pier and beam?
Other?
Thanks.
Because of the expansive soils you should use piers or piles /grade beams and slab on voids. The slab will have to be designed to span between beams.
Ideally you should get a reliable value for skin friction and end-bearing in order to properly dimension the piers.
Now if you can tolerate movement of the soils a thick slab-on-grade could work but will have to be designed as such. Refer to the post-tensionning Institute Publication "post-tensionned slab on ground" for design requirements.