THE DISPLACEMENT OF A MODEL RIGID SURFACE FOOTING ON DENSE SAND UNDER GENERAL PLANAR LOADING

Abstract

Estimation of the displacement of shallow, rigid, sand-supported footings when subjected to general, planar loading and unloading is a fundamental but, as yet, inadequately understood problem. The paper presents extensive new data on the load-displacement response and vertical, horizontal and rotational displacement trajectories of such a model footing derived from a series of precise experiments carried out at the University of Padova. A simple, new transformation applied to both the horizontal and moment load-components, and their associated displacements, is shown to provide a unified interpretation of the results of inclined-central and vertical-eccentric load tests. Displacement trajectories of the footing produced by quite general load-paths, including unloading, are also presented together with a comprehensive set generated by horizontal and moment loading tests at constant vertical load. Key features of the displacement responses are identified and discussed, in particular in relation to the geometrical properties required of a plastic potential curve if the displacements are to be interpreted in a framework of work-hardening plasticity.