Measurement And Research Of Wind-induced Vibration Of Long-span Bridge

With the development of science and technology, bridge spans become larger andlarger. Bridge structure’s becoming longer、thinner、softer and the damping becomingweaker is the inevitable trend, which leads to bridge structure getting more and moresensitive to dynamic effects of wind. In order to ensure bridge structure’s safety andcomfort, it is essential to analyze wind resistance of bridge structures. This paper isbased on a long-span cable-stayed bridge–the North Main Bridge of Xia Zhang Bridgeas the research background, and analyze the buffeting of wind-induced vibration andfield measurement of wind-induced vibration, and make a comparative study betweenthe two results. Based on the above research topic, the main contents of this paper are asfollows:First, on the one hand, this paper reviews the development of long-span bridges,forecasts their future’s development trend and refers briefly to the buffeting ofwind-induced vibration, on the other hand, it provides information about thedevelopment and the necessity of field measurement of wind-induced vibration.Second, the paper introduces two methods of wind field simulation--linear filteringmethod and harmonic synthesis method. According to the AR linear filtering method,use Matlab to establish suitable simulation program, and simulate the fluctuating windvelocity of Xia Zhang bridge over the North Branch of the field by using the program.Third, this paper introduces several types of wind-induced vibration of bridges, andthen summarizes analysis method of long-span bridges buffeting. Finally, it deducescalculation formula of bridge buffeting force according to the quasi-steady theory;according to this formula, based on the simulative fluctuating wind velocity field, andcombined with wind tunnel test results, this paper stimulates buffeting force timehistory of main girders.Fourth, Using ANSYS finite element program, by modeling the Xiamen Zhang Zhoubridge north main bridge and to check whether the model is right, this paper analyzesthe model’s dynamic characteristics. It also analyzes dynamic and time-history byuploading buffeting force time-history to the finite element model, and gets thewind-induced buffeting response analysis results under different conditions.Fifth, this paper introduces wind-induced vibration field measurement of XiamenZhang Zhou bridge north main bridge by using the experimental system, and it mainlymeasures acceleration signal. According to the measured data, this paper analyzes its dynamic characteristics and gets the frequency and damping ratio. In addition, thispaper also analyzes the time history, and the analysis result is compared with that offinite element analysis. Finally, this paper compares and studies buffeting responsescaused by the same average wind coming from different directions.Sixth, this paper summarizes the research, provides some research conclusions, andfinally makes expectations of future work.