Experimental investigation on aerodynamic behavior of a long span cable-stayed bridge under construction

Abstract

Su-tong Bridge is a cable-stayed bridge with a main span of 1088 m whose stiffness is small and it is sensitive to wind action. The length of the bridge girder at maximum single cantilever stage can reach up to 540 m, much attention should be paid in the aerodynamic performances of the under construction bridge. Based on wind tunnel tests, the aerodynamic characteristics of the girder, free standing pylon are considered. Also, field measurements of the pressure distribution on girder surface are presented. The experimental results show that only torsional vibration is found in the smooth flow at wind attack angle of 3°. Considering the influence of turbulence, the vortex-induced vibration of the girder is disappeared. The pressure coefficient values on the upper surface obtained from the wind tunnel tests are relatively larger than that obtained from field measurement. The drag coefficients values obtained from the wind tunnel tests are about 20% larger than that from field measurement. The crane can reduce the amplitude values of the free standing pylon at an incident angle of 0°, corresponding to along bridge axis. The turbulent flow can also reduce the amplitude values of vortex-induced vibration.