地震下城市高架桥横向偏心碰撞响应与防撞效果分析

为适应材料因温度等因素的变化而产生的横向伸缩变形及其对结构的影响，通常梁体与挡块之间会留有一定间隙。针对城市高架桥中梁体与挡块在强震作用下的横向碰撞现象，建立了考虑上部结构与挡块间偏心距和支座非线性的横桥向单墩碰撞模型。采用非线性地震反应时程分析方法，研究了初始间隙及其大小对桥梁结构横向地震反应的影响，并评估了设置橡胶缓冲垫后的防撞效果。研究结果表明：城市高架简支梁桥横向间隙处的偏心碰撞放大了桥墩的地震需求，通过在挡块内侧安装橡胶缓冲垫，可以大幅减小间隙处的碰撞力，将有效改善桥梁结构的横向抗震性能。

Analysis of Eccentric Pounding Responses and Anti seismic Effect of Urban Viaduct Under Transverse Earthquake

To allow for transverse temperature movement, the shear keys are placed with a slight gap from the girders. In this paper, based on pounding phenomenon between girder and shear keys at transverse gaps, a pounding model of single column that considers the eccentric distance between shear keys and girders, and nonlinear behaviors of bearing has been developed. With the time history analysis method of the nonlinear seismic responses, the effects of transverse gap and its size on seismic response of simply supported girder bridges are analyzed, and the effect of installation of the rubber shock absorbing devices inside shear keys is evaluated. The results indicate that the eccentric pounding at the transverse gaps amplifies the responses of piers, and installation of the rubber shock absorbing devices inside shear keys can significantly reduce the impact force between the girder and shear keys and effectively improve the lateral seismic performance.