摘要
目前,利用振型分解反应谱法计算劲性索结构竖向地震位移的解析解还没有被提出,本文在劲性索结构固有振动能量变分解析解的基础上对劲性索结构竖向地震位移解析解及其特性进行了研究.首先根据劲性索结构固有振动能量变分解析解得到劲性索结构各阶固有振动频率和相应的振型;然后利用振型分解反应谱法分别计算40m、65m、72m三种不同跨度劲性索结构的竖向地震位移;最后运用ANSYS有限元软件对此三种不同跨度劲性索结构进行谱分析来验证本文提出的劲性索结构竖向地震位移解析解的正确性.研究发现:(1)三种不同跨度的劲性索结构分别在8度、9度抗震设防下,依据劲性索结构固有振动能量变分解析解与振型分解反应谱法所得到的竖向地震位移曲线与ANSYS有限元软件分析得到的地震位移曲线基本重合,说明本文提出的劲性索结构竖向地震位移解析解适用于计算劲性索结构竖向地震响应;(2)在进行振型组合时,劲性索结构的前两阶正对称振型的组合位移曲线与前四阶正对称振型的组合位移曲线重合,说明劲性索结构的前两阶正对称振型对劲性索结构的竖向振动起控制作用;(3)劲性索结构竖向地震位移曲线的峰值位置并不是都出现在跨中而且曲线峰值个数不止一个,且随着劲性索结构跨度的改变而改变.此现象应该引起工程设计人员的足够重视,在进行劲性索结构设计时应考虑对这些位置采取加强措施,避免劲性索结构因变形过大而发生破坏.
Up to now,analytical solution for the vertical seismic displacement of truss cable structures via modal superposition spectrum method has not been proposed.In this paper,based on the analytical solution of natural vibration of truss cable obtained by the energy variational method,each frequency of natural vibration and mode shape of truss cable structures are obtained.Then,according to the analytical solution of natural vibration of truss cable obtained and the modal superposition spectrum method,the vertical seismic displacement curves of truss cable structures with three different spans of 40 m,65 m and 72 m are presented,and correctness of the analytical solutions above is verified by results of FEM simulations.It is found that:(1)The vertical seismic displacement curves of truss cables with three different spans calculated by the analytical solutions are similar to that calculated by ANSYS under eight and nine degree earthquake fortification,which shows that the analytical solutions presented in this paper is suitable to calculate seismic responses of truss cable structures;(2)When combining the mode shapes of natural vibration of truss cable,results calculated by combining the first two symmetrical mode shapes are same as those calculated by combining first four symmetrical mode shapes,which shows that the first two symmetrical mode shapes take control of the vertical vibration of truss cable;(3)The maximum value of the vertical seismic displacements of truss cables does not always appear in the mid-span of truss cable structure and it changes with the span of truss cable structure.Those new findings could attract designer’s attention and some strengthening measures should be taken for those places.
作者
张文福
杭昭明
李洋
刘迎春
黄斌
严威
华俊凯
王珉
ZHANG Wen-fu;HANG Zhao-ming;LI Yang;LIU Ying-chun;HUANG Bin;YAN Wei;HUA Jun-kai;WANG Min(School of Architecture Engineering,Nanjing Institute of Technology,Nanjing211167,China;School of Civil and Architecture Engineering,Northeast Petroleum University,Daqing163318,China;School of Civil and Architecture Engineering,Suzhou University of Science and Technology,Suzhou215009,China)
出处
《空间结构》
CSCD
北大核心
2020年第1期49-58,共10页
Spatial Structures
基金
国家自然科学基金项目(51178087,51578120)
南京工程学院科研基金项目(YKJ201617)
东北石油大学校青年科学基金项目(NEPUQN2014-25)
关键词
劲性索结构
固有振动
振型分解反应谱法
地震位移
有限元分析
解析解
truss cable structure
natural vibration
modal superposition spectrum method
seismic displacement
finite element analysis
analytical solutions
