Numerical Analysis Of Ductility Of Prestressed Concrete Pipe Pile Under Cyclic Load

Prestressed high strength concrete pipe pile(PHC pipe pile)has the advantages of high bearing capacity,controllable quality and convenient construction.It has been widely used in engineering construction.With the development of PHC pipe pile,its vertical bearing capacity is greatly improved,and the design of reinforced concrete structure should not only meet the requirements of vertical bearing capacity,but also meet the requirements of horizontal bearing capacity and ductility.The problems of pipe pile under the action of horizontal force include low bearing capacity,insufficient plastic deformation and brittle failure.These problems seriously hinder the application and development of pipe pile.Using ABAQUS finite element software,this study applies reciprocating horizontal load to prestressed high-strength concrete pipe pile,studies the effects of different reinforcement ratio,pile type,mixed reinforcement,core filling and pile diameter on the flexural bearing capacity and ductility of pipe pile,analyzes the stress state,failure mode,hysteretic curve,deformation capacity and ductility of pipe pile,and obtains the following conclusions:The stress and strain of pipe pile body,prestressed reinforcement and non prestressed reinforcement are analyzed in the stages of initial,cracking,yield and reaching the limit state of pipe pile.The analysis results show that compared with ab pipe pile,type B pipe pile improves the crack resistance of pipe pile due to the increase of initial prestress,Through the comparative data,it can be found that B-type pipe pile can greatly improve its ultimate bearing capacity;For PRC pipe pile,the core filling has little effect on the cracking moment,but it can slightly improve the ultimate bearing capacity of pipe pile.The three influencing factors of mixed reinforcement,different reinforcement ratio and pile diameter are analyzed.The allocation of non prestressed reinforcement can significantly improve the crack resistance moment and ultimate moment of pipe pile;The greater the reinforcement ratio of pipe pile,the higher the crack resistance and ultimate bearing capacity of pipe pile.By increasing the diameter of the pipe pile,the crack resistance and ultimate bearing capacity of the pipe pile can be significantly improved.Compared with the type AB PHC pipe pile,the bending bearing capacity of type B PHC pipe pile can be significantly improved.Through numerical simulation,it can be concluded that under the action of low cycle reciprocating load,the hysteretic curve of pipe pile is arched,showing a certain "pinch" effect.Compared with B-type pipe pile,the pinch degree of AB-type pipe pile is more obvious,the bearing capacity of B-type pipe pile is higher than AB-type pipe pile,and the energy consumption performance is good;Compared with PHC pipe pile,the bearing capacity of PRC pipe pile is significantly improved,and the load borne by components is more stable during loading.Therefore,PRC pipe pile can effectively improve the bearing performance of pipe pile,with larger displacement ductility coefficient and better ductility.With the increase of reinforcement ratio of PRC pipe pile,its bearing capacity is higher,and it has an obvious improvement effect on the deformation capacity and ductility of pipe pile,and the falling section of load displacement curve is more gentle.The core filled pipe pile has a small increase in the bearing capacity.And the increase of ductility coefficient is obvious.With the increase of pipe pile diameter,the hysteretic characteristics and the shape of skeleton curve have not changed,but the bearing capacity and energy dissipation capacity have been significantly improved,and the ductility is better.