Behavior of Five Large Spread Footings in Sand

Abstract

Five square spread footings ranging in size from 1 mm to 3 mm were load tested up to 150 mm of settlement. They were all embedded 0.75 m into a medium dense, fairly uniform, silty silica sand. Load-settlement curves are presented, as well as creep curves relating settlement and time under a constant load. Since the soil mass was instrumented with telltales and inclinometers, vertical and horizontal movements in the soil mass were obtained as a function of depth and lateral extent. Conclusions are reached regarding how best to measure footing settlement, how to present load test results, new correlations for use in design, creep settlement, effect of cyclic loading and preloading on creep rate, zone of influence under the footing, mode of deformation of the soil mass, and volume change observations. Twelve settlement methods, six bearing capacity methods, and the wave activated stiffness test are evaluated by comparing the predictions with the measurements. Many results of these large-scale instrumented tests confirm findings at small scale of previous researchers.