铁路钢管混凝土系杆拱桥动力特性及地震响应分析

以某铁路钢管混凝土系杆拱桥为研究对象,运用有限元分析软件ANSYS建立了其空间杆系有限元 模型,其中拱肋与系梁采用空间梁单元模拟,吊杆采用空间杆单元模拟,对其动力特性进行了分析;在此基础上运用时程分析方法分别计算了该桥在竖向和纵向地震力组合以及竖向和横向地震力组合两种工况下的地震响应,得到了主拱控制截面在两种荷载工况下的最大内力和最大位移响应,对其抗震性能进行了分析评价.结果表明：该铁路系杆拱桥动力特性总体体现为刚性拱桥的动力特征,横桥向刚度相对较弱,竖向地震力作用下的响应较大,应引起设计注意.研究可为同类型的铁路刚性拱桥抗震设计提供理论依据.

Analysis of the Dynamic Characteristics and Seismic Responses of Railway Concrete-Filled Steel-Tube Tied Arch Bridges

With a railway concrete-filled steel-tube arch bridge as the object of our research, a space finite element model for the rod system is established with help of the Finite Element Analysis Software of ANSYS in the paper, with the arch ribs and tied beam simulated as a space beam unit （beam188） and suspenders simulated as a space rod unit. The dynamic characteristics of the model are analyzed, upon the basis of which the seismic responses of the bridge respectively under the action of both the combination of the vertical and longitudinal seismic forces and the combination of longitudinal and lateral seismic forces are calculated by means of the time-history analysis method, with the maximum internal force and the maximum displacement response of the controlling cross-section of the main arch of the arch bridge obtained and its seismic resistance analyzed and evaluated. It is found that the dynamic characteristics of the railway tied arch bridge, on the whole, are in agreement with those of a rigid arch bridge, with the lateral rigidity of the bridge being relatively weak and the response to the vertical seismic action being relatively great, both of which should be paid attention to in design. The paper may offer a theoretical foundation for the seismic resistance design of railway tied arch bridges of the same type.