Would the Hough Method be an acceptable approach? I have read that this method can over-predict the settlement by a factor of 2 or more. Or, maybe using one of the charts on the Theory of Elasticity or Westergaard's Theory (depending on the subsurface conditions) to calculate the increase in vertical stress beneath a corner of uniformly loaded rectangular area, and multiplying by 4 for the center of the slab. Is the Schmertmann Method an acceptable method? I was told by one of the old PE's that used to work here that it should not be used for mat foundations. I know the analyses of immediate settlement and consolidation settlement; my questions pertains more to cohesionless soils.
I guess my main question is, do you treat the slab as a mat (one large load)? Does a slab-on-grade behave like a mat? I would think the mat would be much stiffer. I feel like I'm losing my mind on this probably not so difficult analysis. I can't find any references that specifically address slab-on-grade settlement.