Steve, I don't think I'm following you there. But after reviewing the FEMA document also I have determined that the lateral modulus would be in the order of 12 MN/m3 and vertical in the order of 2 MN/m3. This "2x" approximation of lateral to vertical is also indicated in Bowles foundation...
The 50 kPa is a factored (95 kPa unfactored) allowable for 25 mm settlement with the local understanding that the foundation is sitting on an overconsolidated crust with soft clay below (likely within 2-3 m). I provide an ultimate factored of 150 kPa for this case. It may be on the lower side...
Hi All,
I have recently come across a new request in my practice. A structural engineer has requested a lateral soil spring for a shallow (both concrete pad [not mat or raft] and steel grillage) foundation. I have provided vertical soil springs for raft/mat foundations and lateral soil springs...
