Investigating Overpass Bridge Damage Indices Using Incremental Dynamic Analysis

Abstract

This study investigates the seismic performance and damage indices of overpass bridges using Incremental Dynamic Analysis (IDA). A case study bridge located in Iran is modeled using SAP2000, considering nonlinear material and geometric behavior. Seven earthquake ground motion records are scaled and applied to the bridge model to evaluate its seismic response. The Park-Ang damage index is employed to quantify structural damage under different seismic intensities. Results indicate that the bridge experiences moderate damage only under the Cape Mendocino earthquake record, while exhibiting slight damage under other ground motions. The study demonstrates that seismic isolation systems can effectively reduce earthquake-induced forces on bridge structures. The findings contribute to the development of fragility curves for seismic vulnerability assessment of overpass bridges.