Calculation And Research On The Ductility Of Concrete Pipe Pile Under Horizontal Load

In recent years,the vertical bearing capacity of pipe pile has been greatly improved with the continuous development of prestressed concrete pipe pile.However,the design of reinforced concrete structures not only requires the requirement of vertical strength,but also the requirement of horizontal ductility,especially in seismic components.At present,there are many experimental studies on the bending and shearing properties of prestressed concrete pipe pile under static action,and there is also little research on its performance under reciprocating load.Researches on the deformation performance and hysteresis characteristics of prestressed concrete piles are more,while there are few studies on the main influencing factors of ductility under larger earthquakes.In this paper,ABAQUS software is used to simulate the influence of four factors(axial load ratio,stirrup strength,volume hopping rate and longitudinal reinforcement ratio)on the ductility of prestressed concrete pipe piles under horizontal load.And the effects of parameters on the concrete pipe pile are studied by comparing the hysteresis curve and the skeleton curve.The results show,1.The axial compression ratio is an important factor affecting the seismic performance of concrete pipe piles.With the increasing axial compression ratio,the ultimate load of the pipe pile increases,but the ultimate displacement reduces,and the capacity of energy dissipation and ductility of pipe pile are both weakened in a certain range.2.The volume hoop rate is also an important factor affecting the performance of concrete pipe piles.The simulation results of hysteresis curve and skeleton curve show that with the increase of stirrup rate,the energy dissipation capacity of pipe pile is obviously improved,and ultimate displacement and ultimate load are also improved.And the ductility of the pipe pile is improved significantly.3.The difference of stirrup strength will also changes the ductility of concrete pipe pile.The results show that with the increase of the strength of the stirrup,the ductility of the pipe pile is improved,but the increase is not significant.4.Under different longitudinal reinforcement stirrup ratio,the ductility of concrete pipe pile also presents different performance.The increase of longitudinal reinforcement stirrup ratio is benefit to the improvement of deformation ability and ductility of pipe pile.The higher the reinforcement ratio,the higher the ultimate displacement of the specimen and the maximum bearing capacity.At the same time,the stiffness attenuate slowly when the descending section of the curve is mild.