Field testing of seismic performance of prestressed high strength concrete piles reinforced with non-prestressed tendons considering pile–soil interaction

Abstract

Prestressed high-strength concrete (PHC) piles have been widely applied as foundations. However, the application of PHC piles was challenging under earthquake hazards. With the increasing demand for PHC piles in earthquake-prone areas, PHC piles reinforced with non-prestressed tendons (PRC piles) were proposed to address the problems. A full-scale field test for one PHC pile and four PRC piles with different non-prestressed tendon ratios (NPTRs) was conducted under horizontal cyclic loading, and their seismic performances were evaluated in terms of hysteretic behaviours, horizontal bearing capacity, ductility, pile deformation, and crack patterns. The results indicated that adding non-prestressed tendons led to an improvement in the hysteresis characteristics and deformation capacity but a decrease in the horizontal bearing capacity. The displacement ductility coefficients of all specimens reached or exceeded 2.8, and there was an optimal NPTR of 0.75% that maximized the ductility of PRC piles, which was 62.5% greater than that of the PHC pile. The pile-soil interaction was considered by analyzing the crack development of the surrounding soil and piles.