Forensic Engineering Evaluation of Excessive Differential Settlement on Compressible Clays

Abstract

This forensic engineering (FE) study evaluated root cause errors associated with excessive differential settlements on a housing project constructed on top of a variable thickness layer of highly compressible clays. The structures were reported to have experienced differential settlements on the order of 2 to 10 in. across 40 ft. The FE study examined fundamental assumptions, granularity/resolution of the settlement and differential settlement analyses, and finalized grading plan vs. the conceptual grading plan used as a basis for the differential settlement predictions. The FE study found numerous discrepancies between the “idealized site” used as a basis of analysis and the “actual site” as constructed.