Wind-resistant Performance Analysis And Experimental Investigation On Long-span Self-anchored Suspension Bridges

With its aesthetics advantage and suitability to soft foundations, the self-anchored suspension bridge becomes an increasingly popular choice in bridge design industry. Although the relevant study on self-anchored suspension bridges started late at home, the ten years since 1999 have witnessed a rapid development in its construction nationwide with spans increasing. Its wind-resistant performance, however, declines due to the relatively low girder stiffness as the anchorage of main cables at the ends of the stiffening girder exerts quite large axial force to the girder. Therefore based on Zhengzhou Taohuayu Yellow River Bridge with a main span of 406m, wind-resistant performance analysis and experimental investigation on long-span self-anchored suspension bridges were carried out in this paper. Specifically the study consists of the following aspects:(1) A comparative analysis was undertaken between the dynamic performance of the self-anchored suspension bridge and that of the earth-anchored one with the same structural parameters. And the effect of variation of structural parameters including boundary conditions, dead load distribution, girder stiffness, stiffness of the main towers, tensile stiffness of main cables and slings on the dynamic characteristics of both self-anchored and earth-anchored suspension bridges was studied.(2) Force, vibration and pressure measurement tests were performed on the section model of main girder. Characteristics of variation of the mean value, standard deviation, skewness and kurtosis of three-component coefficients with wind speed and the angle of attack were studied, and some suggestions were also presented.(3) Soft flutter and vortex induced vibration of a flat box girder section were compared. Studies on the soft flutter amplitude, damping ratio, deviation of torsion center under conditions of various states, attack angles and wind speeds were carried out, and the corresponding reasons were analyzed.(4) Comparison of surface pressure distribution of the model in static state and soft flutter was performed, and the vibration mechanism of flat box girder section was studied through the analysis of the influence of model vibration on the mean value and standard deviation of surface pressure coefficient, torsion correlation of various measuring points, and variation of fluctuating wind pressure power spectrum.