Research On Wind Characteristics And Wind Effects Of Long-Span Cable-Stayed Bridges Based On Structural Health Monitoring

Bridges with much longer span and much lighter structure are emerging along with the rapid development of bridge construction, wind-induced vibration has been one of the most important factors to structural design. Field wind characteristics of Guanhe bridge are obtained based on the structural health monitoring system, flutter and buffeting anlysis of Guanhe bridge are conducted in time domain. The main work is shown as followed:(1) Field wind characterics in normal climate are studied and non-Gauss, non-stationarity of measured fluctuating is confirmed based on structural health monitoring.(2) The aerodynamic coefficients of standard section of Guanhe bridge under normal operation condition are confirmed by 2D fluid simulation with Fluent software.(3) Flutter response of Guanhe bridge is analysed by using ANSYS with the impulse function expression of self-excited force in time domain.(4) Fluctuating wind field of Guanhe bridge is simulated and the buffeting response is analysed based on measured wind spectrum and wind spectrum taken from specification.The main results are as follows:(1) Guanhe bridge is under normal weather conditions with maximum speed of 15m/s during the statistical period, and is mainly affected by northeast wind. There are big difference between measured wind spectrum and some other theoretical spectrums. The masured fluctuating wind is confirmed to Gaussian model and consistent with stationary random process.(2) Great accuracy and rationality are shown in the 2D aerodynamic parameter identification process of bridge sections with Fluent software, and the aerodynamic coefficients of Guanhe bridge under normal operation condition are obtained.(3) The "state assumption" and "restart iteration" methods of bridge structure are put forward to unify the process of bridge flutter and buffeting analysis in time domain.(4) The critical velocity of Guanhe bridge is 172m/s, which is far above the testing speed 47m/s and great influenced by torsional modal damping. The buffeting response of Guanhe bridge under design wind speed is small, and the response with self-excited force is much smaller compared with that without self-excited force. The buffeting response obtained from specification wind spectrum is much greater than that from measured.