Lateral Cyclic Loading Centrifuge Tests on Square Embedded Footing

Abstract

Cyclic lateral loading centrifuge tests were performed on a model of an embedded foundation to study its lateral response at various displacement levels up to ultimate lateral load capacity. The tests simulated a reinforced concrete square, 1.14 m × 1.14 m × 0.84 m high foundation embedded in a dry sand of 75% relative density. The results are relevant to shallow foundations and embedded pile caps. The tests' objective was to evaluate the relative contributions of the base, shearing sides, and active/passive sides of the foundation to the total lateral response as well as any possible interaction between these partial contributions. Lateral response parameters studied included secant stiffness and material damping ratio at various displacement amplitudes and ultimate lateral capacity of the foundation. The lateral stiffnesses measured are compared with available elastic solutions. Three-dimensional static nonlinear finite-element analyses are used to predict the measured lateral load-displacement curves of two of the tests, as well as to confirm analytically the relative contributions of base, shearing sides, and active/passive sides. Thus calibrated, the finite-element model is used to predict the lateral stiffness response of a broad range of embedded footing geometries in sand.