Flexural performance of pretensioned prestressed concrete solid square piles reinforced with steel strands and deformed steel bars

Abstract Pretensioned spun concrete pipe piles and concrete hollow square piles have been subjects of much research interest in recent years; however, their application in practical projects has been limited due to difficulties in effectively guaranteeing the overall performance and durability resulting from the hollow cross‐section. On the other hand, prestressed concrete solid square piles (PSP) that use traditional helical grooved steel bars (HGBs) usually exhibit poor deformability, leading to premature brittle failure under large lateral loads. This paper develops a new type of pretensioned prestressed concrete solid square piles (PSSP), which adopt high‐strength and high‐ductility steel strands as the longitudinal prestressing tendons and deformed steel bars as the erection bars at four corners. Bending tests are carried out on four full‐scale PSSP specimens with different sizes and specifications and one PSP specimen. The results show that PSSP specimens exhibit similar cracking resistance and load‐bearing capacity but better deformation capacity compared to the PSP specimen. The cracks of PSSP specimens are fully developed and uniformly distributed. Compared with the PSP specimen, which exhibits the HGBs rupture failure, the failure modes of PSSP specimens are primarily determined by concrete crushing, showing ductile characteristics. A refined finite element model is established using ABAQUS for the purpose of simulating the flexural behavior of PSSP specimens. After validation, the PSSP‐450A model specimen is used as the benchmark for a parametric study. Numerical results indicate that the maximum mid‐span deflection increases by 28.4% as the pre‐tensioning control stress of steel strands decreases from 70% f ptk to 30% f ptk . Additionally, the load‐bearing capacity increases by 10.8% as the deformed steel bar ratio increases from 0.22% to 0.39%, while a higher steel strand ratio (from 0.32% to 0.58%) leads to a 42.0% increase in the load‐bearing capacity. Reducing the pre‐tensioning control stress of steel strands can significantly enhance the deformation capacity of PSSP. Increasing the steel strand ratio is a more effective method to improve the load‐bearing capacity of PSSP than increasing the deformed steel bar ratio. Finally, the theoretical formulas for the cracking and ultimate moments of PSSP are proposed.