seismic assessment of steel frame bridges and comparison with damage indices

Vulnerability assessment and seismic retrofit of bridges as lifelines is of great importance. In recent years, performance based procedures in bridges is taken into consideration by researchers. In this paper after evaluating proposed methods for seismic performance assessment of bridges, first a laboratory model of box-shaped steel bridge piers was analyzed for verification and results were compared with laboratory data. Then based on the properties of a real bridge, several bridges were designed for parametric studies. The mentioned bridge is continuous and consists of steel moment frames in longitudinal direction. Further, after evaluating performance levels of the bridges, obtained results were compared with damage indices and difference between structural specifications and mentioned indices was indicated. The nonlinear static analysis procedure was used to analyze models. For evaluating damages, energy, effective stiffness and, Park-Ang damage indices were used. Independence of indices from geometric changes of structures, high adaptation of Park- Ang index with energy index due to use of energy as a common concept and more accurate results of energy damage index in each performance level are some of results.