灌浆波纹管装配式桥墩双向拟静力试验

为了解决桥墩与承台的装配式连接问题，提出金属波纹管和超高性能灌浆料的预制拼装桥墩方案。首先考虑施工方式和加载方向参数的影响，以某地铁高架桥为工程原型设计4个试件，然后采用水平单向和双向拟静力试验方法，对比分析金属波纹管节段拼装桥墩和整体现浇桥墩抗震性能的差异，最后探讨双向压弯作用下的极限承载能力验算方法。试验结果表明：灌浆波纹管试件塑性铰区纵筋出现拉断而不是纵筋拔出，说明灌浆波纹管的钢筋连接方式可靠；灌浆波纹管连接节段拼装桥墩损伤过程、破坏模式与整体现浇桥墩总体上接近，主要抗震性能指标的差异较小，认为抗震性能与整体现浇试件的抗震性能接近，表明灌浆波纹管连接是一种可行的装配式桥墩与承台的连接方式；相对于单向加载试件，双向加载的钢筋混凝土试件RC，最大水平力下降11%，极限位移下降18%，双向加载的预制拼装试件最大水平力降低11%，极限水平位移降低15%，残余位移增大了20%，试件损伤程度更为严重，说明在水平双向荷载受力下，整体现浇试件和节段拼装试件有着明显的双向荷载耦合效应；双向压弯作用下截面的弯矩计算方法能够较准确地校核节段拼装墩的极限承载能力。研究成果可为节段拼装桥墩的抗震设计和抗震分析提供参考。

Biaxial Quasi-static Experiment of Precast Segmental Bridge Piers with Grouting Corrugated Pipe Connection

To solve the problem of the assembled connection between a pier and a cap, a prefabricated bridge pier scheme of metal corrugated pipe and ultra-high-performance concrete (UHPC) grouting material is proposed. First, considering the influence of the construction method and loading direction parameters, four specimens were designed with a subway viaduct as the engineering prototype. Second, the uniaxial and biaxial quasi-static test methods were used to compare and analyze the seismic performance difference between the precast segmental bridge pier and the integral cast-in-place pier. Finally, the method of checking the ultimate bearing capacity under horizontal biaxial load was discussed. Results demonstrate that longitudinal reinforcement in the plastic hinge area of the grouting metal corrugated pipe is broken rather than pulled out, indicating that the reinforcement connection of the grouting metal corrugated pipe is reliable. The damage process and failure mode of precast segmental bridge piers with grouting corrugated pipe connection are similar to those of integral cast-in-place piers. As the difference in index of seismic performance is small, the seismic performance of precast segmental pier emulates that of the cast-in-place pier; therefore, the metal corrugated pipe and UHPC grouting material of precast prefabricated pier and cap construction scheme is viable. Compared with the uniaxial loading results, the maximum horizontal force of the integral cast-in-place specimen under the biaxial loading is decreased by 11% and the ultimate displacement is reduced by 18%. Compared with the uniaxial loading results, the maximum horizontal force of the prefabricated assembled specimen under the biaxial loading is reduced by 11%, the maximum horizontal displacement is reduced by 15%, the residual displacement is increased by 20%, and there is more considerable damage in the specimen. Under the condition of horizontal biaxial load, the integral cast-in-place specimen and the segment assembled specimen have obvious biaxial load coupling effects. The bending moment calculation formula under the biaxial bending action can be used to check the ultimate bearing capacity of the segmental bridge pier. The research results can serve as valuable data and reference for future seismic design and analysis of segment piers.