Design of Rigid Pile Caps through an Iterative Strut-and-Tie Model

Abstract

The aim of this work is to present a strut-and-tie model for design of reinforced concrete pile caps. The model considers both failure by crushing of the compressed struts and by yielding of the tie reinforcement. Unlike some traditional models, crushing of the compressed concrete is not checked at the section in direct contact with the column base (column/pile cap interface). In this work, crushing of concrete is verified in a section at a certain depth inside the pile cap. Thus, this verification is replaced by determining the height of the nodal zone at the top of the pile cap required not to cause crushing of the struts. An iterative algorithm is used for this purpose. Comparison with a large number of experimental results available in the literature demonstrates the effectiveness of the proposed model for the design of concrete pile caps. Numerical examples of practical use of the model are also presented.