城市下承式系杆拱桥动力特性与地震响应谱分析

Dynamic Characteristics and Seismic Response Spectrum Analysis of Urban Tied Arch Bridge

为了研究城市下承式系杆拱桥在地震作用下的响应,通过MIDAS建立某城市下承式钢管混凝土系杆拱桥的有限元模型,计算该桥前150阶频率、周期、振型等动力特性,基于城市桥梁抗震设计规范对该桥进行了地震反应谱分析。计算结果表明:本文所研究的下承式钢管混凝土系杆拱桥的拱肋横向刚度相对系梁较小,低阶模型振型中先出现拱肋的振动,再出现全桥振动;E2地震反应谱作用下的响应较大,最大内力(剪力、弯矩、轴力)所在的控制截面位置均不相同。所得结论可以为城市下承式系杆拱桥抗震设计提供参考。

In order to study the response of the urban tied arch bridge under earthquake, a finite element model of a CFSTtied arch bridge was established by MIDAS, and the top 150-order frequency, period and vibration modeof the bridge were calculated. The seismic response spectrum analysis of the bridge was carried out based on the seismic design code of urban bridge. The calculation results show that the arch rib stiffness of the tied arch bridge is small.In the low-order vibration mode, the vibration of the arch rib occurs first, and the full-bridge vibration occurs next. The response under the E2 seismic response spectrum is large, and the maximum internal forces (shear force, bending moment and axial force) are located at different control section positions.. The conclusions obtained can provide reference for the seismic design of the urban tied arch bridge.