| Prestressed high-strength concrete pipe piles are widely used in practical projects due to their advantages of high bearing capacity,convenient construction,and low cost.Because prestressed high-strength concrete is in a complex stress state during use,it is subject to a great deal of verticality.As for the load action,horizontal earthquake action must be considered at the same time.Therefore,it is necessary to study the horizontal bearing capacity of prestressed high-strength concrete and consider its horizontal bearing capacity under horizontal reciprocating load considering the vertical load.In this paper,the finite element analysis of ABAQUS was used to establish the three-dimensional finite element model of prestressed high-strength concrete pipe piles,and the loads were calculated under different vertical pressures(P=4000kN,P=4800kN,P=6000kN).With the horizontal bearing capacity and under repeated loading,the effects of different vertical pressures and the ratio of different steel reinforcements on their bearing capacity and seismic performance were studied.The main contents are:1)With the increase of vertical pressure,the stiffness of the pipe pile has a significant decline;the peak load capacity and displacement of the PHC pipe pile also decreases with the increase of the vertical pressure,indicating the horizontal bearing capacity of the PHC pipe pile As the vertical pressure increases and decreases,the magnitude of the decrease increases,and the deformation ability of the PHC and the ductility of the pile continue to decrease.The horizontal load-carrying capacity of PHC pipe piles under the reciprocating load is lower than that under the one-way loading and the displacement is small,indicating that the PHC piles are degraded in stiffness when they are subjected to reciprocating horizontal loads,the performance is reduced,the bearing capacity is reduced,and their ductility is also Reduced.From the point of view of the equivalent stress cloud diagram of the ultimate failure,the maximum stress of the stirrup occurs near the pile head(bottom).This is due to the fact that under the horizontal force,the bending moment of the pile head is the largest and the shear force is also the largest,so the hoop The ribs also have the greatest equivalent stress.When the longitudinal tendons break down,they reach the yield strength,and the stress at the end is the largest.2)Under the effect of different vertical loads,with the increase of vertical load,the ductility and energy dissipation capacity of the components are gradually reduced.The horizontal bearing capacity of prestressed high-strength concrete tubes decreases with the increase of vertical pressure,and decreases to a nonlinear decrease.When the vertical pressure is P=4800 kN,the maximum bearing capacity of the members is 153 kN.P=4000kN is reduced by 6%;when the vertical pressure is P=6000kN,the maximum bearing capacity of the component is 76.5kN,which is nearly 50% lower than P=4800kN.The horizontal ultimate bearing capacity of a component gradually decreases with increasing vertical pressure.With the increase of vertical pressure,the deformability of the member gradually decreases.3)Under the same vertical pressure,the horizontal bearing capacity of the member increases with the increase of the hoop rate;however,the increasing amplitude of the member decreases with the increase of the vertical pressure value.Stirrup stirrup ratio has little effect on the deformation performance,energy dissipation capacity and ductility of the member under reciprocating action.When the prestressed high-strength concrete pipe pile is finally destroyed,the principal compressive stress of the concrete increases with the increase of the axial pressure,which has little relationship with the stirrup ratio of the stirrup;at the time of ultimate failure,the concrete may not reach the limit.Tensile strength and compressive strength,and stirrups and prestressed steel have yielded,the main damage is the yield of steel bars and stirrups. |
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