Flexural performance of pretensioned spun concrete piles reinforced with steel strands

Abstract

The application of pretensioned spun high-strength concrete (PHC) piles in high-intensity seismic areas has been limited by insufficient horizontal load resistance and poor deformation capacity. A new type of pretensioned spun concrete pile with high-strength and high-elongation steel strands instead of steel bars has been developed. This paper presents a flexural performance evaluation of the new centrifugal spun concrete pile with steel strands (hereafter referred to as a PSC pile). An experimental study is presented first, including bending tests on six full-scale pile test specimens with three different pile diameters. The flexural performances of PHC and PSC piles are comparatively assessed. The results show that the new PSC piles have similar crack resistance, but higher ultimate bearing capacity and better deformation capacity under a flexural condition. Compared with PHC piles, which exhibit a brittle bending failure, PSC piles demonstrate a ductile bending failure. Following the experimental study, a theoretical model is developed to evaluate the flexural strength of the piles, and a simplified calculation equation for ultimate bending moment is proposed. Finally, a finite-element model is established to simulate the flexural performance of the piles; the modelling results are found to be in good agreement with the experimental results.