钢结构环形天桥振动特性测试与分析

Vibration Measurement and Analysis of Steel Annular Pedestrian Overpasses

钢结构环形人行天桥是一种特殊的结构形式。本文以福州市某钢结构环形人行天桥为工程背景,进行了该桥的环境振动和强迫振动试验,利用基于频域法中基于传递率的参数识别方法进行识别与分析人行天桥的动力特性与振动响应。进一步,建立有限元模型对该桥的动力特性进行了理论模态分析,理论计算和实测结果吻合较好,并研究了梁高、墩壁厚参数变化对钢结构环形人行天桥动力特性的影响,为同类结构的振动研究提供参考。此外,建议人行桥舒适度指标允许值参考英国规范BSI,为目前人行天桥所存在的振动问题提出了有益的建议。

Choosing the annular pedestrian overpass on Fuzhou as the engineering background, we did environmental vibration test and forced vibration test. The bridge dynamic characteristics are identified based on the parameter identification method of transmissibility of frequency domain method. The 3 - D finite element models （FEM） are constructed by using MIDAS/civil program and a theoretical modal analysis is then performed to generate natural frequencies and mode shapes in the 3 - orthogonal directions. Then, the variation of dynamic characteristics with beam height and pier thickness parameter change are studied. It provides reference for the research of the same strucure. Otherthen,the comfort of this annular pedestrian overpass is evaluated, the BSI standard may provide a reference for the allowable value of comfort index. This article puts forward suggestions in the vibration problem of the steel annular pedestrian overpass.