基于FVD的双层钢混桁架刚构桥减震效果分析

Analysis on Seismic Mitigation Effects of Double Steel-Concrete Composite Truss Rigid Frame Bridge Based on FVD

为研究大跨度铁路双层钢混桁架刚构桥抗震性能和减震方案,以一座(124+246+124)m三跨铁路双层钢混桁架刚构桥为研究对象,使用非线性结构分析软件建立有限元模型,采用快速非线性分析方法(FNA)研究液体粘滞阻尼器(FVD)在本桥设计参数下的减震率和适用性。结果表明:双层钢混桁架刚构桥墩身自振导致地震力较大,液体粘滞阻尼器参与形成抗震体系后,可协同各墩受力,使得桥梁具有较好结构整体性、稳定性和安全性,墩内力均有一定幅度降低。在控制结构位移方面,液体粘滞阻尼器能有效降低墩梁结构绝对位移,从而缓解罕遇地震力作用下的桥墩损伤。通过对提出的两个减震方案进行对比分析得出结论:仅在主桥小桩号侧桥台设置液体粘滞阻尼器,罕遇地震作用下桥墩墩顶弯矩最大减震率为15.27%,桥墩墩底弯矩最大减震率为21.88%,桥墩墩顶位移最大减震率为27.49%。

To research the seismic performance and seismic mitigation schemes for the long-span railway double steel-concrete composite truss rigid frame bridges, taking a(124+246+124)m three-span railway double steel-concrete composite truss rigid frame bridge as the research object, a finite element model was built with the non-linear structural analysis program, and the fast nonlinear analysis method(FNA) was used to study the shock absorption rate and applicability of liquid viscous damper(FVD) under the design parameters of this bridge. The results show that, since natural vibration of the double steel-concrete truss rigid frame bridge piers may cause significant earthquake force, bridges with FVD are better for entirety, stability and safety, by coordinating the stress of each pier, and internal force of piers can also be reduced to a certain extent. In the aspect of controlling structural displacement, the FVD can also effectively reduce the absolute displacement of piers and beams, and relieve the pier damage of rare earthquakes. By comparing and analyzing two proposed seismic mitigation schemes, it is concluded that under the action of rare earthquakes, the maximum decrease rates of bending moment at pier top and bottom are respectively 15.27% and 21.88%, and the displacement of the pier top is reduced by 27.49% when the FVD is only set on the small pile side abutments of the main bridge.