Flexural tests and numerical simulations of prestressed concrete pipe piles with partial hybrid reinforcement based on support of foundation pits

When the prestressed concrete pipe piles with hybrid reinforcement (PRC pipe pile) are used as the supporting piles of foundation pits, in order to improve the utilization efficiency of non-prestressed reinforcement, it is proposed to use the pipe pile with non-prestressed reinforcement in the section as the supporting piles. Through the statistical analysis of the moment distribution of the supporting piles in 80 foundation pit projects in Tianjin, the full-scale bending tests and finite element analyses of the prestressed high-strength concrete pipe piles with partial hybrid reinforcement (PR-PHC pipe piles), the feasibility of the sectional reinforcement and the bending resistance of the PR-PHC pipe piles are studied. The research results show that the interval distribution of the bending moment of the pile shaft of single support row piles, inclined piles and cantilever piles has regularity. The non-prestressed reinforcement configured in the section of PR-PHC pipe piles can improve its ultimate bending bearing capacity and bending stiffness, and effectively improve the spread of pile cracks. The proposed numerical model can better reflect the actual situation of the tests. In addition, the adverse working conditions that may be encountered in the practical application of PR-PHC pipe piles are analyzed. It is proved that the PR-PHC pipe piles can be used to replace the PRC ones in foundation pit engineering, which reduces the use of reinforcement and promotes the carbon emission reduction.