多联先简支后连续小箱梁桥抗震性能分析

Seismic Performance Analysis of Multi-connected Simply Supported-to-Continuous Small Box Girder Bridge

以某多联先简支后连续小箱梁桥为例,从计算规模确定、抗震设防类别和目标、验算内容和方法、抗震性能和规律等方面对小箱梁桥抗震进行了全面分析。结果表明:多联式小箱梁在E1地震和E2地震作用下,桥墩受力最不利部位均在墩底且受弯控制;E1地震结构处于弹性状态,可通过构件截面初始屈服弯矩判断;E2地震作用下首先采用等效屈服弯矩判断结构是否进入塑性阶段。若结构进入塑性阶段,应重点分析墩顶的位移能力、墩底塑性铰区的转动能力和抗剪强度。研究可为多联小箱梁桥抗震设计和抗震性能评价提供参考。

Focusing on a multi-connected simply supported-to-continuous small box girder bridge,this paper comprehensively analyzed the seismic resistance of the small box girder from the aspects of calculation scale determination,seismic fortification category and objective,checking calculation content and method,seismic performance and law,etc.The results showed that under E1 and E2 earthquakes,the most unfavorable part of the pier force was at the pier bottom and was controlled by bending.Under the E1 earthquake,the structure was in an elastic state,which can be judged by the initial yielding moment of the member section.Under the E2 earthquake,whether the structure enters the plastic phase was determined by the equivalent yielding moment.If the structure enters the plastic phase,the focus should be on analyzing the displacement capacity of the pier top,the rotation capacity of the plastic hinge area at the pier bottom,and the shear strength.This research can provide a reference for the design and evaluation of the seismic performance of multi-connected small box girder bridges.