Dynamic Response of an FRP Footbridge Due to Pedestrians and Train Buffeting
Dynamic Response of an FRP Footbridge Due to Pedestrians and Train Buffeting
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FRP 人行桥因行人和火车抖振而产生的动态响应
DOI：
10.1016/j.proeng.2017.09.411
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Russell J
中科院分区：
文献类型：
--
作者：
Russell J
纤维增强聚合物 (FRP) 是桥梁建设中越来越受欢迎的选择，因为它们具有高强度重量特性和良好的耐用性。特别是，它们非常适合铁路线上的人行天桥，因为它们的安装不会造成太多干扰，并且几乎不需要维护。然而，由于它们通常比传统材料更轻、硬度更小，因此人们担心它们在这些位置的动态响应，这既是由于人类诱发的动作，也是由于火车的震动。在此类事件中，列车运动产生的空气动力载荷会对桥梁产生抖振效应，并可能导致超出行人舒适度极限的振动。目前缺乏这方面的实验信息，如果要在未来的线路上使用此类桥梁，特别是在更高的速度限制下，则需要进一步的数据。本文对一座 14.5m 玻璃钢桁架桥由于人群加载和列车抖振而产生的响应进行了实验研究。首先进行锤子冲击测试，以确定感兴趣的垂直和横向模式及其频率和阻尼。使用一系列加速度计来测量两次人群装载事件（分别有 15 人和 8 人连续行走以及多次火车通过）期间的垂直和横向振动。然后将结果与适用性指南限制进行比较。这些结果加深了对 FRP 桥梁振动响应的理解，可用于帮助设计人员评估此类效应变得至关重要的条件。
Fibre-Reinforced Polymers (FRPs) are an increasingly popular option for the construction of bridges as they possess high strength to weight properties and good durability qualities. In particular, they are well suited to pedestrian bridges over railway lines as they can be installed without much disruption and require little maintenance. However, as they are typically lighter and less stiff than traditional materials there is concern about their dynamic response in such locations both due to human induced actions and as a train buffeting. During such events, the aerodynamic loading from the movement of the train causes a buffeting effect on the bridge and may result in vibrations which exceed pedestrian comfort limits. There is currently a lack of experimental information on this subject, and further data is needed if such bridges are to be used on future lines, especially with higher speed limits.This paper presents an experimental investigation of the response of a 14.5m FRP truss bridge due to crowd loading and train buffeting. First the hammer impact tests were conducted to identify the vertical and lateral modes of interest, and their frequencies and damping. An array of accelerometers were used to measure the vertical and lateral vibrations during two crowd loading events with 15 and 8 people walking continuously, and multiple train passes. The results were then compared to serviceability guideline limits. These results add to the understanding of the vibration response of FRP bridges and can be used to help designers assess conditions in which such effects become critical.