Mechanical models for three and four-pile cap design under centric and eccentric loads

Abstract

Using the results obtained from experimental trials on 30 pile caps tested under centric and eccentric loads, two complementary strut-and-tie models (STM) are proposed: the traditional STM by direct load on piles, and the new STM which describes the vertical thrust along sides of the pile caps. These STMs define the yielding load of the reinforcement, but further load increase after yielding is limited by the punching failure of each pile cap. A punching formulation based on Model Code 2010 is presented. Parameters that define the failure surface are adapted to the particular case of deep pile caps. Conservative predictions and a reduced coefficient of variation confirm the good agreement with the proposal.