Buffeting Analysis In Time Doma In For Long-Span Continuous Steel Truss Beam Arch Bridge

With the development of engineering design, material science and construction technology, the span of modern long-span arch bridge has constantly increased. Wind-induced vibration problems also will become more and more prominent. Buffeting is inevitable during complete bridge status, which affects the bridge's traffic safety and driving comfortableness. The buffeting can be analyzed in both frequency domain and in time domain. Although the analysis process in frequency domain is not complex, it is not applicable to simulate the character of fluctuating wind. The analysis process in time domain can simulate the course of time, moreover, the nonlinearity of structure and wind loads relevance are reflected. So it is appropriate and effective to use the method of time domain.In this thesis, taking a long-span continuous steel truss beam arch bridge as the project background, the buffeting problems of the bridge at operational state are studied. The research is mainly focused on the following aspects:1. The natural properties of fluctuating wind fields is depicted. Based on the formulation of CAWS (Constant Amplitude Wave Superposition), flow chart of the simulation procedure is given. Considering that the wind speed spectrum is vary with the height for the long-span continuous steel arch bridge, the FORTRAN language is employed to program the formulas of the CAWS method。So that the fluctuating wind field is simulated.2. The finite element method theory of the dynamical characteristic analysis is introduced. The spatial finite element modal is established by using the general purpose finite element software ANSYS, then the self-vibration characteristic of the bridge are calculated.3. The basic theory about buffeting and time-domain response spectrum analysis is introduced. The buffeting force is obtained through the quasi-steady theory proposed by Scanlan, taking account of aerodynamic admittances. The aero static analysis and time domain buffeting analysis of the continuous steel truss arch bridge are carried out.4. The work is summarized and some conclusions about the study are drawn, besides, the further research problems are indicated.