灌浆波纹管装配式PC双柱墩双向拟静力试验

为了解双向荷载作用下灌浆波纹管装配式双柱墩的抗震性能，设计和制作了现浇混凝土墩、灌浆波纹管连接和预应力灌浆波纹管混合连接装配式双柱墩构件。开展了装配式双柱墩的双向拟静力试验，研究了破坏模式、滞回特性、骨架曲线、刚度退化、残余位移和接缝张开规律等，并与现浇混凝土双柱墩墩进行比较，重点分析了灌浆波纹管连接装配式预应力混凝土（PC）双柱墩的位移延性和变形性能。结果表明，整体现浇墩和波纹管连接装配式双柱墩的破坏形态均是以弯曲破坏为主的延性破坏，预应力增大了轴压，使得双柱墩的柱脚混凝土压碎高度增大到15 cm，而灌浆波纹管连接装配式混凝土墩的柱脚破坏高度为10 cm。双向荷载作用下，现浇墩的耗能能力、极限承载力、刚度等均大于灌浆波纹管装配式墩。增加预应力筋后，装配式双柱墩强轴方向的滞回耗能、承载力、刚度和变形能力等可以接近现浇墩，其中承载力达到现浇墩的97.9%。位移延性系数为4.79，大于现浇墩的位移延性系数3.23，残余变形则降低到现浇墩的70%。同时，预应力灌浆波纹管装配式墩2个方向的位移延性和变形能力更为接近，均可以形成完全塑性铰机制，从而避免了一个方向的过早破坏，整体抗震性能明显提升。研究结果可以为灌浆波纹管装配式PC双柱墩的设计和应用提供试验基础。

Bi-axial Quasi-static Experiment for Assembled Double-column Piers with Grouting Metal Corrugated Pipe and Prestressed Tendons

To investigate the seismic performance of grouting metal corrugated pipe( GCP)-assembled concrete double-column piers under biaxial loads,three test specimens,including the cast-in-place( CIP),GCP and prestressed GCP( PGCP) piers,were designed and fabricated. Bi-axial quasi-static tests were conducted to study the failure modes,hysteretic characteristics,skeleton curves,stiffness degradation,residual displacement,and joint opening rules for the GCP and PGCP piers,and compared with those of the CIP pier. The analysis on the displacement ductility and deformation capacity of the PGCP pier was emphasized. The results show that the bending failure fails to dominate the CIP and GCP specimens,and the prestressed force increases the axial load and damage degree,thereby increasing the crashed concrete height of the PGCP pier to 15 cm in contrast to that of the GCP pier( 10 cm). Under the bidirectional load,the energy dissipation and ultimate bearing capacities and stiffness of the CIP pier are higher than those of the GCP pier. After adding prestressed tendons,the bearing capacity,stiffness,and deformation capacity of the PGCP pier in the strong axis direction are approximately equal to those of the CIP pier. The bearing capacity of the PGCP pier reaches 97. 9% of that of the CIP pier. The displacement ductility coefficient( 4. 79) of the PGCP is higher than that of the CIP pier( 3. 23). The residual displacement of the PGCP pier decreases to 70% of that of the CIP pier. Furthermore,the displacement ductility and ultimate deformation capacity of the PGCP pier in two directions are almost similar,indicating that the full plastic hinge mechanism in two directions can be formed to avoid early failure in one direction,and the overall seismic performance of the PGCP pier is significantly improved.The results can provide an experimental basis for the design and application of the PGCP pier.