Experimental shear test of deep PHC piles reinforced by infilled concrete and shear rings

Abstract

This paper presents experimental shear tests of pretensioned spun high-strength concrete (PHC) piles reinforced by infilled concrete and shear rings with shear span-to-depth ratio of less than 2.0. Seven specimens are designed and fabricated, where the longitudinal reinforcement ratio and presence of shear rings and sludge are set as key variables. The load–deflection responses and crack patterns of the specimens, strain behavior of shear rings, and composite action between the PHC pile and infilled concrete are measured and analyzed comprehensively. Based on the experimental results, this study examined whether the current design codes, which are section-based models, are appropriate for designing PHC piles with infilled concrete. In addition, a strut and tie model is proposed to estimate the shear strengths of PHC piles with circular cross-sections and different material properties. The analysis results show that the code equations can be used for the shear design of deep PHC piles reinforced by infilled concrete and shear rings in a conservative manner, and that the proposed strut and tie model considering different material characteristics of the PHC piles and infilled concrete provides good evaluation results.