BEHAVIOUR OF VERTICAL PILES UNDER REVERSIBLE LATERAL LOADS

Abstract

An experimental investigation is reported on the behaviour of vertical piles under reversible lateral loads. The model pile used was a long one corresponding to a case of driven pile in a sand deposit of uniform density. The pile head was free and lateral loads were applied at ground level such that complete cycles, consisting of loading and unloading in two opposite directions were obtained. Four different load levels were tried and in one the maximum number of cycles was thirty one while in others it was ten cycles only. The data from the tests was obtained in the form of loads and corresponding deflections at ground level for various cycles and hysteresis loops thus obtained form the basis of the discussions and conclusions. The effect of the increasing number of cycles was found in general to impart the soil pile system a constancy regarding deflections and damping characteristics. It was indicated that for smaller load levels steady state was achieved at comparatively a lesser number of cycles. Dimensionless plots are also given for the pile behaviour with number of cycles at one load level. A brief review of literature pertaining to the hysteretic damping 2 • in soils and available information on lateral load tests under repeated and reversible loading is included. Certain suggestions for further investigations in this field which has little available. information and details of a proposed set up for loading to a very large number of cycles are also given.