大跨度悬挑组合楼板人致振动响应测试分析

Test and Analysis of Human Induced Vibration Response of Long-span Cantilever Composite Floor

为研究大跨度悬挑组合楼板在人群荷载作用下的振动响应规律,对某实际楼板进行现场测试。测试识别楼板的前3阶模态,并通过合理设置工况来研究人群活动类型(行走和跑步)、步频、活动路径对楼板振动响应的影响规律,着重探究静止人阻尼效应对楼板振动响应的影响。结果表明,与行走相比,人群跑步引起的楼板振动响应更加显著,跑步激励下楼板各个测点的振动加速度大约是行走的1.55~2.64倍;在人群同步行走时,不同步频激起楼板的竖向振动模态不同,步频2.1Hz激起楼板的竖向3阶模态,2.3Hz激起竖向1阶模态;在步频与活动类型相同的情况下,人群在不同活动路径上运动时激起楼板不同的模态,并且距离活动路径中心线0m处测点的振动峰值加速度普遍较大;静止人阻尼效应抑制了楼板在人群活动下的主要振动模态,使得楼板的振动响应有所减少,人群以步频2.1 Hz行走时楼板上各个测点的振动峰值加速度减少约7.75%~59.41%,2.3Hz时减少约13.98%~50.17%。

In order to study the vibration response of the long-span cantilever composite floor under crowd load,the field test of a floor slab in reality was carried out.The first three modes of the floor were tested and identified,and the influence law of crowd activity type(walking and running),stride frequency and activity path on the floor vibration response was studied by setting the working condition reasonably,focusing on exploring the influence of static human damping effect on the floor vibration response.The results show that compared with walking,the vibration response of the floor caused by crowd running is more significant,and the vibration acceleration of each measuring point of the floor caused by running is about 1.55~2.64 times that of walking.Under the synchronous walking of the crowd,the vertical vibration modes of the floor aroused by different footings are different.The third vertical mode is aroused by the footings at 2.1 Hz,and the first vertical mode is aroused by 2.3 Hz.Under the condition of the same step frequency and activity type,the floor modes are different when the crowd moves on different activity paths.Moreover,the peak vibration acceleration at the measuring point 0 m away from the center line of the active path is generally larger.The main vibration modes of the floor under crowd activities are suppressed by the static person damping effect,which makes the peak vibration acceleration of the floor reduced by 7.75 %~59.41 % when walking at 2.1 Hz and 13.98 %~50.17 % at 2.3 Hz.