Experimental Study of Aerodynamic Disturbance Effect of Existing Bridge on Main Girder of Under-Construction Cable-Stayed Bridge

In this paper, the under-construction Hanjiang River Bridge of the reconstruction and expansion project of Beijing-Zhuhai Expressway is used as a case to study the aerodynamic disturbance effect of an existing continuous rigid-frame bridge on the main girder of an under-construction cable-stayed bridge. Wind tunnel tests were carried out with a 1: 50 segmental model of the main girder to study the influence of multiple factors on the three-component coefficients of the under-construction cable-stayed bridge, including the locations of the two bridges, the distance of the two bridges and wind attack angles. The results show that the existing bridge can introduce distinct aerodynamic disturbance effect on the under-construction bridge. An upstream existing bridge exerts obvious shielding effect, which causes overall decrease of dragging coefficient of the under-construction bridge. A downstream existing bridge can cause distinct reduction of the dragging coefficient of the under-construction bridge within the range of positive attack angles. Due to the influence of the existing bridge, the absolute value of lift coefficient is globally reduced, at positive attack angles, the reduction is more obvious when the existing bridge is downstream of the under-construction bridge. At positive attack angles, the pitching moment coefficient of the under-construction bridge is increased under the influence of an upstream existing bridge, while globally reduced under a downstream bridge, and the situation is opposite at negative attack angles. The distance of the existing and under-construction bridges has distinct influence on the aerodynamic disturbance effect of dragging coefficient, the bigger the distance, the weaker the aerodynamic disturbance effect on the dragging coefficient of the under-construction bridge, however, the aerodynamic disturbance effect on the lift coefficient and pitching moment coefficient is minimal. © 2023 Wuhan Bridge Research Institute. All rights reserved.