弹性支承块式轨道桥梁结构地震响应分析

为研究弹性支承块式轨道结构对地震作用下桥梁结构位移、内力的影响,以某3跨预应力混凝土连续箱形高架轨道桥为例,利用Midas Civil软件建立考虑和不考虑具体轨道结构形式的高架轨道桥梁有限元模型,分析典型地震波作用下该高架桥梁的地震响应。结果表明:考虑具体轨道结构形式模型的连续梁桥主梁的位移、跨中正弯矩、支点负弯矩及支座处剪力均明显小于不考虑轨道结构形式模型的相应值,对主梁结构来说,设计中不考虑轨道结构形式是一种偏安全的设计方法,而考虑轨道结构模型的桥墩墩顶位移可能大于不考虑轨道结构形式模型的相应值,为安全起见,在进行轨道桥梁桥墩的抗震设计时应当考虑具体轨道结构形式的影响。

Seismic Performance Analysis of Elastic-block Supporting Rail Transit Bridge

To study the influence of elastic-block supporting track structure on the displacement and internal force of bridge system under earthquake,a three-span continuous prestressed concrete box-girder elevated track bridge is referenced. The elevated track bridge finite element models are established with Midas Civil software respectively with and without the consideration of the specific form of track structures to analyze seismic responses of the viaduct subject to typical seismic waves. The results show that displacement of bridge girders,the positive moment at the mid-span,and the negative moment and shear force at the supported place indicated by the model with the consideration of the specific track structures are significantly less than the corresponding values from the model without. But,it is somewhat a safer design method without the consideration of the specific form of track structures as far as the main beam structure is concerned. Whereas,the pier top displacement calculated from the model considering the track structure may be larger than that from the model without considering the track structure. For the sake of safety,the specific form of track structures should be carefully considered in the seismic design of piers of track bridges.