Analysis Of Wind Characteristics And Wind Effects On A Cable-stayed Bridge Based On Field Monitoring

For the long-span bridge, it is very flexible and the damping is small. Therefore, the bridges are more readily oscillate dramatically subjected to wind, i.e. the wind becomes dominant load for the design of bridges. In order to obtain wind field char-acteristics on the actual long-span bridge, wind effects on the bridge and overcome the limitation of wind tunnel test technology (such as size effect), It is necessary to monitor the wind field on the bridge and the response of the bridge. On the one hand, we can study the wind characteristics, wind effects and their mechanism of bridges based on field measurement, On the other hand, It also can validate the wind tunnel test results and simulation results. Therefore, based on the data obtained form struc-tural health monitoring systems (including monitoring system of wind and wind ef-fects) of a cable-stayed bridge, we investigates wind characteristics and wind in-duced vibration monitored on a cable-stayed bridge. The mean wind speed and direc-tion, power spectral density, the turbulent intensity and integral length of wind in flow at two cross-sections are investigated and are compared with each other. In ad-dition, considering the non-stationary characteristics of wind, The time-frequency characteristics of the fluctuant wind and. the time-frequency spatial correlation are analyzed using wavelet transform. The flow characteristics around the bridge deck at two positions are also investigated using the field measurement. The relationship between acceleration response of the bridge and mean wind speed is analyzed. It is worth note that, when opening for traffic, the increasing trend of the acceleration with the mean wind speed is more obviously then no traffic. The dynamic character-istics of the cable-stayed bridge were also determined based on field measured ac-celeration signals. The results indicate that, with the mean wind speed increase , the total modal damping ratios of the bridge increase, however, the frequencies of the bridge almost keep constant.