预制拼装铁路重力式桥墩的抗震性能研究

Study on Seismic Performance of Prefabricated Railway Gravity Piers

为适应中国铁路建设向高烈度震区快速发展的需要,解决传统预制拼装桥墩墩柱及承台连接位置薄弱等问题,提出一种灌浆波纹管连接的模块化预制拼装桥墩体系,通过设置承台与墩身塑性区域共同浇筑及墩底局部无黏结段增强桥墩的抗震性能。制作1个局部无黏结整体现浇铁路重力式桥墩模型和1个局部无黏结预制拼装铁路重力式桥墩模型开展拟静力试验,并结合有限元分析,进行预制拼装铁路重力式桥墩抗震性能研究。结果表明:局部无黏结预制拼装桥墩整体连接性能稳定,可通过墩底塑性区域破坏与墩身及节段间的摇摆实现共同消能,其破坏模式表现为墩底塑性区域的弯曲破坏,未发生破坏位置转移现象;局部无黏结预制拼装桥墩等效塑性区域高度比整体现浇桥墩降低,抗侧向水平承载力与耗能能力提升显著,位移延性能力良好,可适应更大加载位移,最终累积耗能增长64.3%;结构接缝位置连接稳定可靠,同等加载位移下等效刚度基本一致,抗震性能得到明显提高;预制节段划分对预制拼装铁路重力式桥墩抗震性能的影响不大。

To meet the needs of the rapid development of railway construction to high-intensity seismic areas in China,a modular prefabricated bridge pier system with grouted corrugated tube connections is proposed to solve the problems of weak connection positions between pier columns and caps of traditional prefabricated piers.By pouring the pier cap and the plastic region of the pier body together and setting a locally unbonded segment at the pier bottom,the seismic performance of the bridge pier is strengthened.A model of locally unbonded monolithic cast-in-place railway gravity pier and a model of locally unbonded prefabricated railway gravity pier were created to carry out pseudo-static tests,and the seismic performance of prefabricated railway gravity pier was studied by finite element analysis.The results show that the overall connection performance of the locally unbonded prefabricated bridge pier is stable,and it can dissipate energy through the swing between the plastic region at the pier bottom and the pier body and segments.The failure mode of the locally unbonded prefabricated pier is characterized by bending failure in the plastic region at the pier bottom,without damage location transfer phenomenon.Compared with the locally unbonded cast-in-place bridge pier,the locally unbonded prefabricated pier has a reduction in the height of the equivalent plastic region,and its lateral bearing capacity and energy dissipation capacity are significantly improved.It also exhibits good displacement ductility and can adapt to larger loading displacement,with an increase of the final cumulative energy consumption of 64.3%.The joint position of the structure is stable and reliable,the equivalent stiffness is basically the same under the same load displacement,and the seismic performance is obviously improved.The precast segment division has little influence on the seismic performance of prefabricated railway gravity pier.