structured slab on grade

[agnoyes]

I have a project with undocumented fill and the geotechnical engineer has recommended a structured slab on grade?

Would the cost be the same as an elevated framed system ($30/sf) or more like a slab on grade ($7 /sf)?

I think the only cost savings would be the formwork which could be considerable. Maybe $20/sf for this structured slab on grade between grade beams?

 

[KootK]

Is there any potential for the fill to heave? If so, it's common to lay down some void form which can offset the form work savings a bit.

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.

 

[jayrod12]

I would expect it to be somewhere in between, the reinforcing will be more than a slab on grade but only nominally, it's the cost of the voidform as KootK noted that will be the driving factor.

There will also likely be beams and foundations below a structured slab on grade as opposed to just a standard slab on grade.