Seismic Analysis and Design Optimization of a Self-Anchored Suspension Bridge

The seismic performance analysis and design optimization of a self-anchored suspension bridge is studied in this paper. Based on the preliminary design of the bridge, a finite element model has been built for performing structural dynamic analysis. For time history analysis of the bridge subjected to seismic excitation, generated artificial site-specific earthquake waves were adopted as the ground motion input. The seismic performance objectives have been set for the bridge when earthquake events of expected intensities occur. The structural dynamic characteristics of the bridge have been obtained by performing modal analysis. In order to improve the seismic performance of the bridge, the tower design has been optimized and nonlinear fluid viscous dampers have been applied at the points of intersection between the two towers and the deck of the bridge. The parametric sensitivity analysis has been conducted on the design parameters of the dampers to determine a proper combination. Nonlinear time history analysis has been performed for the bridge. The analysis results show that the expected performance objectives of the bridge can be reached after the optimization of the towers design and the installation of dampers.