Uplift Load‐Displacement Behavior of Spread Foundations

Abstract

The design of spread foundations for uplift loads is based primarily on capacity considerations, largely because there has been only a limited effort to characterize the load‐displacement response of these foundations. This paper examines the results of 75 full‐scale field tests and synthesizes the results in a convenient design procedure that incorporates estimated displacements. The effects of soil type (granular versus cohesive) and foundation type (steel grillage versus concrete slab or steel plate) are investigated, and it is found that: (1) Granular soils lead to a slightly stiffer response than cohesive soils in the initial portion of the load‐displacement curve; and (2) slab or plate foundations lead to slightly stiffer response than grillages for granular soils only. The type of foundation has little influence for cohesive soils, and for practical purposes, a single generalized load‐displacement relationship can be used to represent the available data for all four cases at the 95% confidence level.