Equivalent Modulus of Subgrade Reaction for EPS Insulation under Slab
Equivalent Modulus of Subgrade Reaction for EPS Insulation under Slab
(OP)
I'm curious if anyone has approximated a modulus of subgrade reaction for rigid foam insulation beneath concrete slabs.
I see regular foam board used in residential construction frequently - not the 40-100 psi hi-test variety that is preferred for under slab use. I am curious how you would compensate in design, other than assuming some arbitrary and low value for k.
I see regular foam board used in residential construction frequently - not the 40-100 psi hi-test variety that is preferred for under slab use. I am curious how you would compensate in design, other than assuming some arbitrary and low value for k.






RE: Equivalent Modulus of Subgrade Reaction for EPS Insulation under Slab
How could you do anything so vicious? It was easy my dear, don't forget I spent two years as a building contractor. - Priscilla Presley & Ricardo Montalban
RE: Equivalent Modulus of Subgrade Reaction for EPS Insulation under Slab
RE: Equivalent Modulus of Subgrade Reaction for EPS Insulation under Slab
How could you do anything so vicious? It was easy my dear, don't forget I spent two years as a building contractor. - Priscilla Presley & Ricardo Montalban
RE: Equivalent Modulus of Subgrade Reaction for EPS Insulation under Slab
RE: Equivalent Modulus of Subgrade Reaction for EPS Insulation under Slab
I think that when dealing with 40 or 50psf LL the insulation likely will 'react' to enough of an extent that the slab still performs like a slab on grade, and does not develop enough flexural stress to justify spanning across footings.
My 4" slab with #4's at 16" o/c is good for little more than 1k'. A passenger vehicle would induce a moment many times higher than that if I consider my slab spanning 20'.
RE: Equivalent Modulus of Subgrade Reaction for EPS Insulation under Slab
RE: Equivalent Modulus of Subgrade Reaction for EPS Insulation under Slab
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RE: Equivalent Modulus of Subgrade Reaction for EPS Insulation under Slab