Softened Strut-and-Tie Model for Shear and Flexural Strengths of Reinforced Concrete Pile Caps

Abstract

Reinforced concrete pile caps are important structural elements transmitting vertical loads from the structure to the ground. The performance of pile caps is complex, with a wide range of structural parameters in play, such as geometry, tension reinforcement, pile arrangement, and so on. Their complexity and criticality demand a good degree of reliability in strength estimations. Current design approaches are devoid of contribution from key parameters, resulting in inaccurate strength estimations. Moreover, there are interpretation difficulties when using the existing code provisions for members with pile arrangements that are not too simple. A general approach considering the influence of critical parameters for estimating the strength of pile caps in shear and flexure is proposed in this paper. The proposed approach can capture the accurate contribution of nondominant load paths, typically observed in pile caps with nonsymmetric pile arrangements. The model predictions for 21 specimens with varying parameters and failure modes are compared with test strengths and American design code (ACI) code estimations. Results showed an excellent correlation with test results, better than code estimations, showing the accuracy and efficacy of the proposed model.