锥套锁紧连接预制装配桥墩抗震性能试验研究

Experimental study on seismic performance of prefabricated pier with taper sleeve locking connection

节段有效连接是保证预制装配桥墩正常使用的关键。锥套锁紧连接是一种新型钢筋连接形式,操作简便,连接高效,但尚无应用于预制装配桥墩的详细研究资料。以某拟建轨道交通高架桥梁预制装配桥墩为工程背景,考虑现浇连接(CIP),锥套锁紧连接(TS)和套筒灌浆连接(GS)3种方式,设计制作了3个1︰3的桥墩缩尺试验模型,完成了拟静力试验和数值仿真分析,对比了不同连接方式桥墩的破坏形式、承载能力、刚度退化和自恢复能力。研究结果表明:锥套锁紧连接应用于预制装配桥墩,其等同现浇程度显著优于套筒灌浆连接。3种连接方式的试件最终破坏形态均为典型弯曲破坏,表现为墩身与承台接缝处的裂缝贯通以及柱角区域混凝土压溃,但现浇连接和锥套锁紧连接试件的裂缝沿墩身基本呈环向均匀分布,套筒灌浆连接试件的裂缝较为集中于套筒连接区段接缝处。锥套锁紧连接试件承载能力、塑性转动能力基本等同现浇,残余位移和自恢复能力次之,耗能能力最差;套筒灌浆连接试件的承载能力和耗能能力较前二者都高,其中承载能力较锥套锁紧连接提升了34.3%,但延性系数降低了23.8%。相比于增大恒载轴压比,增大墩身纵筋配筋率可有效提升锥套锁紧连接试件耗能能力和承载能力,同时较小程度损失试件的延性和自恢复能力。研究成果为锥套锁紧连接预制装配桥墩的设计和应用提供了详细技术参考。

Effective connection between segments is critical to ensure the normal service of prefabricated pier.Taper-sleeve locking is a new type of reinforcement connection,which is easy to operate and efficient to connect.However,there is no detailed research data on its application in prefabricated pier.Based on the engineering background of prefabricated piers of a proposed rail transit viaduct bridge,three test specimens with reduced scale of 1:3 were designed and fabricated,considering different connection type,namely cast-in-place connection(CIP),taper-sleeve locking connection(TS)and sleeve grouting connection(GS).The pseudo-static tests and numerical simulation analysis were completed.The failure forms,bearing capacity,stiffness degradation and self-recovery ability of the specimens were compared.Results show that TS connection is significantly more similar to CIP connection than GS connection.The final failure forms of the three specimens are typical bending failure,presented with the through cracks around the joint section between pier and cap,and concrete collapse in the column angle area.However,the cracks of CIP and TS specimen are uniformly distributed in the ring direction along the pier Those of GS specimen are more concentrated in the joint section.The load-bearing capacity and plastic rotation capacity of TS specimen are basically the same as those of CIP specimen,followed by the residual displacement and self-restoring capacity,and the energy dissipation capacity is the worst among the three specimens.The bearing capacity and energy dissipation capacity of GS specimen is both higher than those of the previous two.Compared with TS specimen,the bearing capacity of GS specimen is 34.3%higher while the ductility coefficient is 23.8%lower.Compared with the axial compression ratioincrease,the longitudinal reinforcement ratio increase can effectively improve the energy dissipation capacity and bearing capacity of TS specimen with little losing the ductility and self-recovery ability.The research results of this paper can provide a detailed technical reference for the design and application of prefabricated pier with taper-sleeve locking connection.