Reliability-Based Design of Seismic Retrofit for Bridges

This research focused on developing reliability-based seismic retrofit assessment procedures for highway bridge columns. Fragility curves were developed to assess the relative performance of various retrofit methods considering several limit states. Analytical fragility curves are developed from scaled earthquake records and structural response models. A simplified, single-degree-of-freedom (SDOF) structural model was assumed to reasonably represent the structural response of the bridge columns for this research. The structural configuration, geometry, and properties of the bridge columns came from Washington State Department of Transportation standard bridge designs. Scaled earthquake data were used to calculate the displacement history during the prescribed earthquakes, and structural displacement, ductility and dissipated energy were determined to calculate damage indices (DI). Various retrofit methods were selected from the literature. For the retrofitted cases, different degrees of increase in mass, stiffness, damping, and ductility were taken from the literature, over those of the un-retrofitted structure.