摘要
人行天桥动力特性是影响桥上行人舒适度的主要因素。针对随机人群行走对人行天桥模态阻尼比和模态频率的影响,考虑人-人相互作用的行人步态主被动调整策略,基于考虑行人同步率的随机人群集中模型,推导了随机人群-人行天桥-TMD系统的耦合动力方程,分析了人行天桥动力特性参数时变规律,提出了基于人行天桥动力特性参数时变的TMD减振设计方法。结果表明:考虑人-人相互作用时,在随机人群行走下,人行天桥一阶瞬时阻尼比随人群密度的增大而大幅提高,提高的幅度与人行天桥基频和模态质量呈正相关;在随机人群行走下,人行天桥一阶瞬时频率随人群密度的增大而不断下降,降低的幅度与人行天桥基频呈负相关。基于人行天桥动力特性参数时变的减振设计方法能有效地减小单人定频行走、单人随机行走和随机人群行走下结构的竖向振动响应,其中0.6人/m^2随机人群行走工况下,人行桥竖向振动加速度减振率达到72%。
Dynamic characteristics of footbridge are the main factors that affect the comfort level of pedestrian on the bridge. Based on the influence of random crowd walking on modal damping ratio and modal frequency of pedestrian bridge, considering the active and passive gait adjustment strategy of human-human interaction, a stochastic crowd concentration model dependent on the pedestrian synchronization rate was established. The coupling dynamic equation of random crowd-footbridge-TMD system was deduced. The time-varying law of dynamic characteristic parameters of footbridge was analyzed. The TMD vibration control design method based on time-varying dynamic characteristic parameters of footbridge was proposed. The results show that the first instantaneous damping ratio of the footbridge increases greatly with the increase of the crowd density under random crowd walking when the human-human interaction is considered, and the increment is positively correlated with the fundamental frequency and modal quality of the footbridge. The first instantaneous frequency of the footbridge decreases continuously with the increase of the crowd density under random crowd walking, and the decrement is negatively correlated with the fundamental frequency of the pedestrian bridge. The time-varying dynamic characteristic parameters of the footbridge based on vibration control design method can effectively reduce the vertical vibration response of single person walking at fixed frequency, single person randomly walking and random crowd walking. Under the case of 0.6 person/m^2 random crowd walking, the reduction rate of vertical footbridge vibration acceleration reaches 72%.
作者
操礼林
曹栋
李爱群
CAO Lilin;CAO Dong;LI Aiqun(Faculty of Civil Engineering and Mechanics,Jiangsu University,Zhenjiang 212013,China;School of Civil Engineering,Southeast University,Nanjing 210096,China;School of Civil and Transportation Engineering,Beijing University of Civil Engineering and Architecture,Beijing 100044,China)
出处
《建筑结构学报》
EI
CAS
CSCD
北大核心
2020年第11期134-142,共9页
Journal of Building Structures
基金
国家自然科学基金重点项目(51438002)
国家自然科学基金项目(51408267)
关键词
人行天桥
人致振动
随机人群
TMD
振动分析
人-人相互作用
footbridge
human-induced vibration
random crowd
TMD
vibration analysis
human-human interaction
作者简介
操礼林,出生于1979年,男,工学博士,副教授,主要从事工程结构振动分析与减振控制研究。email:cll@ujs.edu.cn
