Research On Wind-induced Vibration Effect Of S-shaped Curved Cable-stayed Bridge

Curved cable-stayed bridges are sometimes used due to the restrictions of topography and geomorphology or to meet the requirements of linear connection at both ends of bridge heads.Due to the complex linear shape of curved cable-stayed bridges,the spatial structure is sensitive to wind load,and there are few relevant researches.This dissertation combines practical engineering,taking an S-shaped curved cable-stayed bridge as an object,and the wind-induced vibration effect of the bridge is studied.Specific work and related conclusions are as follows:(1)Using CFD numerical simulation method,set up to five types of wind attack angles,namely-5°,-3°,0°,+3°and+5°,and the static three-component force coefficient of the main beam of S-curved cable-stayed bridge is solved in FLUENT.(2)The whole bridge beam element model is built in ANSYS,the modal analysis of curved cable-stayed bridge is carried out,and the natural vibration frequency and mode are analyzed.Based on the wind speed increment method,ANSYS is used to simulate the whole process of nonlinear static instability of S-curved cable-stayed bridge,judge the critical wind speed of static wind instability and compare it with the result calculated by the empirical formula of wind resistance standard,the iterative solution result is less than the calculated result of the empirical formula,which proves that the whole process simulation of nonlinear static instability of cable-stayed bridge is more safe.(3)The whole bridge plate and shell element model is established in ANSYS,and the curved cable-stayed bridge is loaded with static gust load,the control variable method is adopted,the structural displacement response of curved cable-stayed bridge under the action of different wind speed,wind direction and angle of attack are analyzed.The results show that the displacement of the bridge structure presents a nonlinear change with the increase of wind speed,and the wind angle of attack increases,the structure displacement increases,and the bridge is most sensitive to the wind from the transverse bridge.(4)Davenport pulsating wind spectrum is selected and MATLAB is used for numerical simulation of the pulsating wind field at the bridge position,a pulsating wind loading program is developed in ANSYS to analyze the structural buffeting response of S-curved cable-stayed bridge under the action of pulsating wind,the displacement response RMS value of cable-stayed bridge under different wind speed,wind direction angle and angle of attack was calculated,and the displacement value under static gust wind load is compared and analyzed,the results show that the buffeting response of cable-stayed bridge considering the influence of fluctuating wind is basically the same as that of displacement under the action of static gust wind.