摘要
针对风雨耦合作用下桥梁主梁的涡激振动问题,首先从降雨特性及其对结构的作用入手,考虑雨滴冲击和降雨引起的结构表面积水,探讨了对应模型与原型雨强相似比,并依据主梁振动和降雨设备的特点对相似关系作了适当简化,然后以4类典型主梁断面为例,实现了不同雨强和攻角下的节段模型动力特性与涡激振动试验。结果表明:随着雨强增大,结构振动频率有所降低,而阻尼比有所增加,试验雨强为120 mm·h-1时,频率降低1.5%~3.5%,阻尼比增加了0.05%~0.15%,考虑雨强相似比后实际降雨对频率的影响可忽略,对阻尼比的影响也相当小;涡振的起始和结束风速以及区间数目基本不随雨强的变化而变化,但有雨时的振幅比无雨时小,试验雨强较大时,振幅减小明显,考虑雨强相似比后试验雨强120mm·h-1的原型值均超过615mm·h-1左右的中国雨强极值,其对涡振响应的影响非常有限。
Aiming at the problem that bridge girder＇s vortex vibration during coupling effect of wind and rain,firstly,according to the characteristics of rainfall and its effect on structure,the rain intensity similarity ratio between model and the prototype was discussed respectively with the angle of rain drop impact and structure＇s surface water accumulation caused by rainfall,and the corresponding simplified rain intensity similarity ratio was derived on the basis of the characteristics of the main girder＇s vibration and the rainfall equipment.Then,section models of four typical main girders were taken as the example to test dynamic characteristics and vortex induced vibration under different rainfall intensity and attack angle.The results show that the structure＇s natural frequency decreases and damping ratio increases with the increase of rainfall intensity respectively.When the test rainfall intensity is 120 mm·h^-1,the frequency reduces by1.5%-3.5%,and the damping ratio increases by 0.05%-0.15%.Considering the similarity ratio of rainfall intensity,the actual rainfall＇s effect on frequency can be neglected,and its effect on damping ratio is also very small.The initial and ending wind speeds and the number of intervalsof vortex vibration don＇t change with the change of rainfall intensity.The amplitude of the vortex vibration under coupling effect of wind and rain is less than the result of no rainfall.In the experiment,the reduction is very obvious under heavy rain,but considering the similarity law of rainfall intensity used,the prototype value of experimental rainfall intensity of 120 mm·h^-1 exceeds the extreme rainfall intensity of 615 mm·h^-1 in China,so the actual rainfalls have very limited influence on the response of the vortex vibration.
作者
雷旭
陈政清
华旭刚
黄智文
聂铭
肖凯
LEI Xu;CHEN Zheng-qing;HUA Xu-gang;HUANG Zhi-wen;NIE Ming;XIAO Kai(Electric Power Research Institute of Guangdong Power Grid Co. Ltd. , Guangzhou 510080, Guangdong, China;Wind Engineering Research Center, Hunan University, Changsha 410082, Hunan, China)
出处
《建筑科学与工程学报》
CAS
北大核心
2018年第3期54-62,共9页
Journal of Architecture and Civil Engineering
基金
"十二五"交通运输重大科技专项项目(2011 318 824 140)
中国南方电网有限责任公司科技项目(GDKJQQ20153010)
关键词
桥梁工程
主梁
风雨耦合作用
相似比
动力特性
涡激振动
bridge engineering
main girder
coupling effect of wind and rain
similarity ratio
dynamic characteristics
vortex induced vibration
