Axial Compression And Coring Of PHC Pipe Pile And Cap Joint Simulation Analysis Of The Effect Of Shear Capacity

With the development of civil engineering,high-strength pre-stressed concrete pipe pile(PHC pipe pile)is more and more used in construction projects.The mature technology and advantages of pre-stressed concrete pipe pile make PHC pipe pile become the common pile foundation of high-rise buildings.Many kinds of pipe piles have been applied in foundation engineering and are the pile foundation materials of many important buildings.Relevant studies have found that the liquefaction of foundation soil often leads to shear failure at the junction of soft and hard soil layer and the joint between pile cap and pile end.Therefore,filling reinforcement can be carried out at the joint of pipe pile and cap to improve the shear bearing capacity of piles.In pile foundation engineering,PHC pipe pile will not only be subjected to horizontal load,but also to the vertical load transmitted by the upper structure through the cap,the vertical load will inevitably affect the shear bearing capacity of PHC pipe pile.On the basis of previous studies,the shear capacity of hollow and filled PHC pipe piles under certain axial compression conditions is simulated and analyzed by ABAQUS finite element software.The effects of axial compression and filling on the shear capacity of the connections between PHC pipe piles and caps are discussed.The following conclusions are drawn:(1)Under certain conditions of axial compression,axial compression can improve the shear bearing capacity of PHC pipe piles.The larger the axial compression,the higher the cracking shear force and ultimate shear force.However,the shear failure mode of PHC pipepiles has not changed.The axial compression ratio has a linear relationship with the ultimate shear force of PHC pipe piles.The existence of axial compression can reduce the stress of pile concrete,spiral stirrups and the transverse displacement of PHC pipe piles.With the development of the structure,the displacement of the damaged structure decreases to a certain extent.(2)For reinforced concrete and steel-reinforced concrete cored PHC pipe piles under certain axial compression conditions,the influence of axial compression on their shear capacity and failure mode is basically the same as that of hollow PHC pipe piles under axial compression,and there is no significant difference between them.(3)The influence of ordinary reinforced concrete filling and steel reinforced concrete filling on the shear capacity of PHC pipe pile is higher than that of axial compression.The filling delays the development of spiral stirrup stress and axial stress of pile concrete,and increases the displacement of pipe pile when it is damaged.However,with the increase of axial compression,the displacement of PHC pipe pile with core filling tends to decrease.(4)Based on the existing formulas for calculating the shear capacity of PHC pipe piles,and combined with the simulated analysis values,the formulas for calculating the shear capacity of PHC pipe piles considering the axial compression and different filling forms are derived.The formulas are verified by the relevant experimental data,and they are in good agreement with each other,which can provide a reference for further theoretical research.