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Wind and Structures
  Volume 29, Number 6, December 2019, pages 417-430
DOI: http://dx.doi.org/10.12989/was.2019.29.6.417
 


Wake effects of an upstream bridge on aerodynamic characteristics of a downstream bridge
Zhenhua Chen, Haojun Tang, Yongle Li and Bin Wang

 
Abstract
    To study the wake influence of an upstream bridge on the wind-resistance performance of a downstream bridge, two adjacent long-span cable-stayed bridges are taken as examples. Based on wind tunnel tests, the static aerodynamic coefficients and the dynamic response of the downstream bridge are measured in the wake of the upstream one. Considering different horizontal and vertical distances, the flutter derivatives of the downstream bridge at different angles of attack are extracted by Computational Fluid Dynamics (CFD) simulations and discussed, and the change in critical flutter state is further studied. The results show that a train passing through the downstream bridge could significantly increase the lift coefficient of the bridge which has the same direction with the gravity of the train, leading to possible vertical deformation and vibration. In the wake of the upstream bridge, the change in lift coefficient of the downstream bridge is reduced, but the dynamic response seems to be strong. The effect of aerodynamic interference on flutter stability is related to the horizontal and vertical distances between the two adjacent bridges as well as the attack angle of incoming flow. At large angles of attack, the aerodynamic condition around the downstream girder which may drive the bridge to torsional flutter instability is weakened by the wake of the upstream bridge, and the critical flutter wind speed increases at this situation.
 
Key Words
    two adjacent bridges; horizontal and vertical distances; aerodynamic interference; static coefficients; dynamic response; flutter stability
 
Address
Zhenhua Chen, Haojun Tang, Yongle Li and Bin Wang: Department of Bridge Engineering, Southwest Jiaotong University, Chengdu 610031, China
Zhenyun Lin: Department of Bridge Engineering, Southwest Jiaotong University, Chengdu 610031, China;
HaiXia (Fujian) Transportation Engineering Design Co., Ltd., Fuzhou 350004, China
 

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