【摘要】 大跨度拼装式桥梁是一种沿导梁推送架设的应急桥梁,其动力响应分析属于变截面梁在推送移动状态下的振动响应分析。首先利用瑞利法建立该工况下的动力学方程并求解,再利用空间有限元法建立振动系统模型并进行数值计算,最后利用基于无线传输方式的环境激励测试系统进行测试并分析,三者结果吻合较好,得到了外界激励应避开一阶竖向或横向固有频率、结构体系竖向振幅远大于横向、架设设备两侧机构不均衡会导致扭转振动等结论,为大跨度拼装式桥梁架设使用和动力响应分析提供技术支持。更多还原

【Abstract】 Large span assembled bridge is a kind of emergency bridge pushed to erect along the guide beam, whosevibration response analysis is that of varying cross-section beam in push moving state. This paper firstly appliesRayleigh method to establish the dynamic equations under moving conditions and obtains the solutions. Then it us-es spatial finite element method to establish the finite element model of the vibration system and calculate the ana-lytical results. Finally with wireless transmission a modal test of large span bridge under ambient excitation is car-ried out to get relevant test results. Results from the three kinds of methods for dynamic vibration characteristicsare consistent. This study concludes that the external excitation should avoid the first order natural frequency ofvertical or transverse vibrations; the vertical amplitude of structure system is much larger than the transverse am-plitude; and the imbalance of mechanisms on both sides of the erection device will cause the torsional vibration. Itprovides a technical support for erecting operation and dynamic response analysis of erecting large span assem-bled bridges.更多还原