基于桥面-拉索-阻尼器耦合振动的索力测试合理拾振位置研究

Study on Rational Picking-Up Position of Cable Force Based on Coupling Vibration of Deck-Cable-Damper

以厦漳跨海大桥2根安装外置阻尼器的长短索索力测试为背景,引入实际存在的环境激励,通过有限元方法研究拉索在桥面-拉索-阻尼器耦合振动下,拉索外置阻尼器附近不同采集点信号的频谱分析效果。结果表明:外置阻尼器对阻尼器位置拾振点、外置阻尼器与桥面之间拾振点的频谱分析效果影响明显,短索基本识别不出频率,长索可勉强识别少数几阶频率;受外置阻尼器与现场测试条件的限制,索力测试时拾振器的合理安装位置应选在外置阻尼器上部,距外置阻尼器的距离等于阻尼器距桥面距离的拉索上。

Based on the long short cables ＇ cable force of two external dampers installed in Xiamen-Zhangzhou Cross-sea Bridge,the actual excitation of environment is introduced. In this paper,the finite element method is used to study the spectral analysis of signals collected near cable dampers at different acquisition points under coupling vibration of deck-cable-damper. Results show： the external damper has obvious influence on spectral analysis on the vibration pick-up point at the damper and on the pick-up point between the external damper and the bridge deck. Frequency is hardly identified on short cable and a few frequencies can barely be identified on long cable. Restricted by external dampers and field test conditions,during cable force test,the rational installation location of the vibration pick-up should be on a cable above the external damper,distance between the pick-up and external damper shall be the same with that between the damper and the deck of bridge.