焊接接头腐蚀对预应力高强混凝土管桩抗震性能影响的有限元分析

针对地震作用下预应力高强混凝土管桩的受力特性问题，考虑焊接接头腐蚀的影响，应用ABAQUS有限元软件建立管桩-土体三维模型，采用拟静力的方法对管桩顶部施加水平低周往复荷载来模拟地震荷载，研究了竖向荷载与焊接接头的腐蚀程度对PHC管桩抗震性能的影响，并提出了增配非预应力筋的改善措施。结果表明，竖向荷载的存在会降低管桩的耗能能力，而提高管桩的水平极限承载力；焊接接头处焊缝的应力最大，在焊接接头腐蚀后率先发生屈服，管桩的水平极限承载力随着焊接接头腐蚀程度的增大而降低，其造成的影响不容忽视；通过在桩身配置一定数量的非预应力筋能降低焊接接头处焊缝的应力，同时能够有效改善管桩的耗能能力，提高管桩的水平极限承载力，从而降低焊接接头腐蚀对管桩抗震性能的不利影响。

Finite Element Analysis of the Effect of Corrosion of Welded Joint on Seismic Performance of PHC Pipe Pile

In view of the mechanical characteristics of prestressed high-strength concrete (PHC) pipe piles under seismic action, considering the effect of corrosion of welded joint, the three-dimensional model of pipe pile-soil was established by using finite element software ABAQUS. The seismic load was simulated by applying horizontal low cyclic loading on the top of the pipe pile by using the pseudo-static method. The influence of vertical load and corrosion degree of the welded joint on the seismic performance of PHC pipe piles was studied, and the improvement measure of adding non-prestressed rebars was put forward. The results show that the existence of vertical load can reduce the energy-dissipation capacity of pipe piles and improve the horizontal ultimate bearing capacity of pipe piles. The stress of the weld seam at the welded joint is the largest, and it is the first to yield after the corrosion of welded joint. The horizontal ultimate bearing capacity of the pipe pile decreases with the increase of corrosion degree of welded joint, which can not be ignored. By equipping a certain number of non-prestressed rebars in the pile body, the stress of the weld seam at the welded joint can be reduced, and the energy-dissipation capacity of the pipe pile can be effectively improved, and the horizontal ultimate bearing capacity of the pipe pile can be increased, so as to reduce the adverse effect of corrosion of welded joint on the seismic performance of the pipe pile.