Investigation of reasonable shock absorption of asymmetric long-span suspension bridges considering force differences

Abstract

Compared with conventional suspension bridges, asymmetric long-span suspension bridges exhibit significant differences in the forces of key members on different sides under earthquake action, due to their uneven mass and stiffness distributions. In this study, the seismic response characteristics of an asymmetric long-span suspension bridge were analyzed using the Guangdong Xijiang Special Bridge as a case study. The shock absorption laws of the asymmetric parameter combinations of the viscous dampers for each control target were investigated. Accordingly, a response surface model for each control objective was established based on the response surface method. The objective function was constructed based on the principle of reducing the differences in multi-target seismic responses on different sides. Finally, a particle swarm optimization algorithm is used to determine the optimal combination of parameters for the viscous dampers on both sides. The results show that the seismic response of the members on the higher-mass side is more evident for an asymmetric long-span suspension bridge under earthquake action. Members on the smaller-mass side have a better shock absorption effect. After optimization using the proposed method, the average optimization magnitude of each control objective reached 23.1%, compared with the traditional symmetric parameters. The optimal combination of the asymmetric parameters of the viscous dampers on both sides can equalize the full-bridge forces and improve the shock-absorption effect of the dampers. The proposed method has a referable meaning for shock absorption control of asymmetric structures.