波纹钢管约束承插式拼装桥墩抗震性能研究

Seismic Performance of Precast Socket Piers Confined with Corrugated Steel Pipe

承插式预制拼装桥墩是将预制混凝土墩柱插入承台预留的凹槽内,在间隙中填充混凝土或灌浆料连接形成的装配式结构,承台预留槽内设置波纹钢管以增强对桥墩根部的横向约束。开展承插式拼装桥墩和现浇桥墩2组试件的拟静力荷载试验,研究了承插式拼装桥墩的抗震性能以及波纹钢管的横向约束效应,并通过相关影响参数的模拟分析,探讨了承插深度、灌浆料强度和连接界面处理方式对承插式桥墩抗震性能的影响规律,为其抗震设计提供依据。研究结果表明:波纹钢管约束承插式桥墩柱脚形成的塑性铰区域及破坏形态与现浇桥墩基本一致,承载能力没有明显差异,但破坏时极限位移提高约20%,结构延性和耗能能力有所提高,波纹钢管约束承插式拼装桥墩具有良好的整体性和抗震性能;随着承插深度的增加,承插式桥墩的抗震性能随之提高,当承插深度超过0.6D(D为墩身直径)时,其抗震性能提升趋于缓和;当灌浆料强度达到桥墩主体混凝土强度后,继续增加强度对桥墩抗震性能影响不大;相对光滑界面连接,波纹键齿和梯形键齿连接的承插式桥墩承载能力分别提高约30%和26%,累积耗能分别提高20%和15%,波纹键齿连接的效果最优。

The precast socket pier,a type of prefabricated structure,is connected by embedding a precast pier into a groove reserved in a bearing platform and filling concrete or grouting materials in the gap.A corrugated steel pipe is placed in the reserved groove of the bearing platform to strengthen the lateral constraint on the root of the pier.In this study,quasi-static load tests of two groups of specimens of precast socket pier and cast-in-place pier were conducted.The seismic performance of the precast socket pier and the lateral constraint effect of the corrugated steel pipe were studied.And through the simulation analysis of the relevant influence parameters,the influence of socket depth,grouting material strength and connection interface form on the seismic performance of precast socket piers were discussed,providing the basis for the design of precast piers.The results show that the size of the plastic hinge region and failure mode of the corrugated-steel-pipe-restrained precast socket pier are consistent with those of the cast-in-place pier.The bearing capacity of the socket pier is similar to that of the cast-in-place specimen.The ultimate displacement at failure of the socket pier is increased by 20%,and the ductility and energy dissipation capacity are improved.The corrugated-steel-pipe-restrained precast socket pier has good integrity and seismic performance.With the increase of socket depth,the seismic performance of the precast socket pier is improved.However,when the socket depth exceeds 0.6D,the improvement of seismic performance tends to ease.When the strength of the grouting material reaches that of the concrete of the precast socket pier,the strength of the grouting material has little effect on the seismic performance of the pier.Compared with the smooth contact interface,the bearing capacity of the socket pier connected by corrugated key teeth and trapezoidal key teeth is increased by about 30%and 26%,and the cumulative energy consumption is increased by 20%and 15%respectively,where the seismic effect of the socket pier connected by corrugated key teeth is the best.