Dynamics of Civil Structures, Volume 2 - Proceedings of the 38th IMAC, A Conference and Exposition on Structural Dynamics 2020
Dynamics of Civil Structures, Volume 2 - Proceedings of the 38th IMAC, A Conference and Exposition on Structural Dynamics 2020
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土木结构动力学，第 2 卷 - 第 38 届 IMAC 会议论文集，2020 年结构动力学会议和博览会
DOI：
10.1007/978-3-030-47634-2_14
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
White R
中科院分区：
文献类型：
--
作者：
White R
在过去的几十年里，行人诱发的振动在各种人行天桥上造成了严重的问题，因为它可以导致结构振动的幅度突然增加，即横向动力失稳。在英国克利夫顿悬索桥上的两个不同的人群加载活动中进行了测量，以描述观察到的人与结构之间的相互作用。对桥梁的两种横向模式进行了研究，以前发现它们对行人诱导的激励很敏感。通过一种基于时频分析的新方法，对不同的桥面振幅响应进行了对比研究，以确定不同的相互作用。这使得能够识别行人装载过程中瞬时振型振幅和共振频率的波动。克利夫顿悬索桥在人群荷载作用下的测试结果表明，这两种振型的自振频率都有显著提高。这两种模式的瞬时频率似乎大致反映了250名行人在大负荷下的位移幅度响应。最近对克利夫顿悬索桥在人群荷载作用下的测量表明，在低振幅响应期间存在人-结构相互作用的初步证据。对于高幅响应，发现振型频率随振型的增大而增大，表现出两种振型的复杂的非线性硬化效应。
Pedestrian-induced vibrations have caused significant issues on various footbridges, over the past few decades, as it can lead to an abrupt growth in the amplitude of structural oscillations, i.e. lateral dynamic instability. Measurements were taken during two separate crowd loading events on the Clifton Suspension Bridge, UK, to characterise the human-structure interactions observed. Two lateral modes of the bridge were studied, previously found susceptible to pedestrian-induced excitation. A comparative study is performed to identify the different interactions observed for the differing bridge deck amplitude responses through a novel procedure based on time-frequency analysis. This enables the identification of the fluctuations on the instantaneous modal amplitude and resonant frequency during pedestrian loading. Previous measurements of Clifton Suspension Bridge during crowd loading leading to the onset of large-amplitude vibrations revealed a significant increase in the natural frequency of the two modes considered. The instantaneous frequency, of both modes, appeared to roughly mirror the displacement amplitude response during significant loading, >250 pedestrians. Recent measurements of Clifton Suspension Bridge during crowd loading, illustrated tentative evidence for the presence of human-structure interactions during low-amplitude responses. For high amplitude responses on the bridge the modal frequencies were observed to increase with an increase in amplitude displaying a complex non-linear hardening effect for the two modes of vibration.