PARAMETER OPTIMIZATION OF LEAD RUBBER BEARINGS OF AN ISOLATED CURVED GIRDER BRIDGE

In order to improve the performance of an isolated curved girder bridge with lead rubber bearing (LRB), the mechanical parameters of LRB are analyzed and optimized. Firstly, the finite element model of a three-span isolated curved girder bridge is established by ANSYS. Nonlinear time history analyses are conducted with consideration of impact of yield force, elastic stiffness and post-yield stiffness. It is found that the key seismic responses of structure vary with mechanical parameters. The reasonable ranges of the parameters of isolated bearings are determined. Taking the sum of the pier base shear as the objective function, the mechanical parameters of LRB are optimized based on the zero-order optimization algorithm. Results show that yield force, elastic stiffness and post-yield stiffness have significant effect on seismic responses of the isolated curved girder bridge. When the bearings parameters are optimized, the peak displacement of the bearings is effectively controlled without increasing the base shear of the piers distinctly. The differences of shear between the side piers and the middle piers are reduced, and the shear distribution of each pier becomes uniform.