Study On Buffeting Response Of Chao Tianmen Bridge Under Construction

With the applications of high-strength materials and advanced construction technology, bridges has developed into those of long span, small rigidity and light weight. These bridges are sensitive to wind load due to their small rigidity and low frequency. Too much buffeting response caused by turbulent flow will not damage the bridge but lead to local fatigue of the bridge, make people uncomfortable, cause vehicles at a high speed in danger and so on. Hence, the analysis of bridge buffeting should be a major part of bridge wind resistance design. In this paper, the author analyzes Chao tianmen Bridge buffeting response under construction by full aeroelastic bridge model wind tunnel test by the following three steps.Firstly, the dynamic behaviors of Chao tianmen Bridge under four different construction conditions are analyzed, frequencies under the four different conditions are got by Ansys, and frequencies of model bridge are obtained by principle of similarity, thus, the framework of model bridge is designed.Secondly, full aeroelastic bridge model is made and full aeroelastic bridge model wind tunnel tests under four different conditions are achieved.Thirdly, based on the analysis of test data, conclusions are drawn as follows: In turbulence field and uniform flow field under the four different construction conditions, and in different angles, wind speed increases from 0m/s to 8.5m/s, galloping and obvious vortex shedding are not found, nor are emanative flutter of girder and static duckling of main arch and girder. Acceleration RMS of the deck and the arch as well as displacement response RMS are not big in each angle. In turbulence field, displacement RMS of the deck is somewhat bigger when compared to that of the main arch. There is a small difference between displacement response RMS of the main arch under main arch maximum cantilever position and that under main arch 1/4 cantilever position when the wind speed is about 40m/s, which means there's no obvious seakeeping performance degradation of the bridge under main arch maximum cantilever position, the so-called the most unfavorable condition.