Feasibility of improving shear performance of RC pile caps using various internal reinforcement configurations: Tests and finite element modelling

Abstract

The loads from columns and bridge piers are transferred to the pile foundation by reinforced concrete (RC) pile caps, which are important structural components whose behavior is significantly affected by the internal reinforcement configuration. Therefore, the current study experimentally investigates the shear response of RC pile caps by testing nine specimens have identical dimensions and various reinforcement configurations. The experimental matrix is designed to study (i) the influence of using a closed transversal reinforcement along with the presence of an upper reinforcement only or an upper and side reinforcement together. (ii) Behavior of RC pile caps internally reinforced with various closed-side bars’ area and (iii) the impact of the interaction between the longitudinal reinforcement of the piles and the column in the presence of upper reinforcement only or side closed bars solely. RC pile cap specimen internally reinforced with closed transversal reinforcement with upper reinforcement and 12 mm-diameter closed side bars can be considered the optimal reinforcement form due to the fact that this specimen achieved the highest ultimate load and toughness of 1286 kN and 1089 kN.mm, respectively. Moreover, the current research involves the development of a three-dimensional (3D) non-linear finite element model to evaluate the response of RC pile caps while taking into account concrete's tensile strength and softening behavior in either tension or compression. Results of the numerical model well agreed with the experimental data. Additionally, a parametric study is conducted using the verified model to examine the impact of utilizing bent bars positioned perpendicular to the shear crack's direction on the ultimate load, failure pattern, and toughness of the RC pile caps.