Capacity versus Deformation Analysis for Design of Footings and Pile Foundations

Abstract

Measurements of settlement of a piled raft supporting a 40 grain elevators and of five furnaces on piled foundations showed that the settlements were unrelated to deformation due to load transfer from individual piles to the soils and instead governed by compression below the pile toe level. Full-scale static loading tests on footings and pile toes in sand showed that the soil response is not that of building up to an ultimate value, but instead due to gradually increasing compression of the soil below the footing or pile toe. Pile toe movements from 26 piles founded in sand, although showing a scatter of soil deformation response, confirm the results of the footing test. The findings are used to reaffirm the principle that design of a piled foundation requires the analysis of the interaction between load transfer, soil settlement, and pile toe load-movement response.