Experiment on Vortex Vibration of Bridge Main Girder’s Section Model Under Coupling Effect of Wind and Rain(PDF)
《建筑科学与工程学报》[ISSN:1673-2049/CN:61-1442/TU]
- Issue:
- 2018年03期
- Page:
- 54-62
- Research Field:
- Publishing date:
Info
- Title:
- Experiment on Vortex Vibration of Bridge Main Girder’s Section Model Under Coupling Effect of Wind and Rain
- Author(s):
- 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.
- Keywords:
- bridge engineering; main girder; coupling effect of wind and rain; similarity ratio; dynamic characteristics; vortex induced vibration
- PACS:
- -
- DOI:
- -
- Abstract:
- 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 by 1.5%-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 intervals of 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.
Last Update: 2018-05-31