支座激励下端部带水平减震装置悬索的动力分析  

Dynamic analysis of the suspended cable with horizontal mitigation devices at one end subject to support excitations

作　　者：张鹏[1] 王国威 卢文胜[2] 周祺 ZHANG Peng;WANG Guowei;LU Wensheng;ZHOU Qi(School of Architectural and Surveying&Mapping Engineering,Jiangxi University of Science and Technology,Ganzhou 341000,China;State Key Lab of Disaster Reduction in Civil Engineering,Tongji University,Shanghai 200092,China)

机构地区：[1]江西理工大学土木与测绘工程学院,江西赣州341000 [2]同济大学土木工程防灾国家实验室,上海200092

出　　处：《振动与冲击》2023年第24期298-307,共10页Journal of Vibration and Shock

基　　金：江西省教育厅科技项目(GJJ210820);江西理工大学校级纵向科研项目(205200100550);国家自然科学基金(52178501)。

摘　　要：近年来工程中常将索网幕墙直接支承在两相邻结构上,在地震作用下两相邻结构的相对位移将引起索网幕墙破坏,造成安全隐患。针对相邻结构间单向索采光顶,提出在悬索端部附加水平减震装置来减小悬索的地震响应。水平减震装置包括弹簧和阻尼装置,弹簧装置可以减少悬索的地震输入,而阻尼装置可为结构提供附加阻尼;建立了端部带减震装置悬索的动力模型,推导了频率及模态阻尼比的计算公式,分析结构的阻尼特性,对支座激励下端部带减震装置悬索进行动力试验,检验了减震效果。结果表明:悬索动力特征系数αb^(2)、刚度系数γ_(k)及阻尼系数ν是控制结构振动特性的3个无量纲关键参数,为了给悬索提供足够的附加阻尼,建议在工程上ν取值0~150,γ_(k)取值0~1;经减震装置参数的合理设置,悬索的动索力和动位移可减小30%以上。αb^(2)较小或支座激励远离悬索自振频率时可仅在索端部设置弹簧减震装置,αb^(2)较大且支座激励接近悬索自振频率时需设置弹簧阻尼减震装置。In recent years,cable net fa ades are often used to provide cover between adjacent structures.However,there are safety hazards that the relative displacements of adjacent structures may cause the damage of cable net fa ade under earthquake.Therefore,for one-way cable daylighting roofs between adjacent structures,additional horizontal mitigation devices comprising springs and dampers at the end of cables were proposed in this paper to reduce seismic responses of the facades.Specifically,the horizontal damping device is composed of the springs which can reduce seismic energy input to the suspension cable and the dampers which provide additional damping.In this research,a theoretical model of suspended cable with the mitigation device at one end was established.Furthermore,the frequency and damping formulas were derived to analyze the damping properties of the suspended cable.In addition,the mitigation effect was verified by the dynamic response tests of the suspended cable attached with this additional device attached subjected to supported excitations.Results show that the dynamic feature coefficient αb^(2),stiffness coefficient γ_(k),and damping coefficientνare three dimensionless key parameters to control the vibration properties of suspended cables.In practical engineering,it is recommended thatνshould be set between 0 and 150 andγk should be set from 0 and 1 to provide sufficient additional damping for suspended cables.It must be noted that the dynamic cable force and displacement can be reduced by exceeding 30%through reasonably setting the parameters of the damping device.For cables with a small αb^(2) and support excitations away from the cable natural frequencies,only springs are sufficient for mitigation,while for cables with a large αb^(2) and support excitations close to the cable natural frequencies,the end springs and dampers can significantly reduce responses of suspended cables.

关 键 词：悬索 水平减震装置 模态阻尼比 支座激励 动力响应 

分 类 号：TU382[建筑科学—结构工程]