Study On The Buffeting Time Dependent Reliability Of Single Tower Cable-Stayed Bridge

The response of bridge buffeting is extremely complex phenomenon. When turbulent wind flowing around moving bridges, because of the mutual action between components of turbulence and motion, various wind-resulted vibrations are disturbed by each other, moreover, some complex effects, such as the wind dynamic coupling and the coupling of all phases of vibration mode, make the precise calculation of response of buffeting extremely difficult.In this dissertation, taking Shenzhen Gulf Bridge as engineering example, on the basis of analytical theory of buffeting in the frequency/time domain,the dynamic reliability study of buffeting on single tower cable-stayed bridge is carried out. According to the characteristic of wind field on bridge main deck, WAWS is utilized to simulate the fluctuating wind velocity time history. By use of the explicit decomposition of the wind velocity spectrum density matrix and the FFT technique, the efficiency of simulation is improved greatly. The time domain transformation of self-exited force is realized by the means of adding aerodynamic stiffness and aerodynamic damping element to FE model. With the modification of aerodynamic admittance function, Scalan' s theory is introduced to establish the corresponding buffeting theory in the frequency domain. On the basis of first passage mechanism, the dynamic reliability of structure is studied. Based on the buffeting response analysis in the time domain, several dynamic reliability formulas are evaluated by means of numerical simulation method.A computer program dealing with buffeting response in the frequency and time domain is completed by the author to calculate the displacement variance of buffeting response ofhenzhen Gulf Bridge under different wind velocities and angles, ts worst condition is introduced and its dynamic reliability s evaluated. The critical wind velocity and frequency of luting of ideal plate are also calculated in this dissertation nd its results are in conformity with the analytical ones.