Component-level seismic fragility of a typical highway bridge in a moderate intensity zone

The seismic fragility of typical highway bridges in moderate-intensity zones is investigated. The seismic fragility and extensive infrastructure destructions are severe on critical highway bridge components during and after significant seismic activity in moderate intensity zones, particularly in the main rift valleys region of Ethiopia (MRVRE). This article aims to determine the seismic fragility and seismic demand, develop a fragility curve, predict the probabilistic seismic demand model (PSDM), and samples using nonlinear identify the interdependence of typical highway bridge components in a moderate-intensity zone using a component-level approach. The bin technique has been used to record output data for 154 analytical bridge-ground motion finite element analysis. The intensity of a seismic event has been determined by utilizing peak ground acceleration (PGA) and high-level ground motion duration. Meanwhile, column ductility has been identified as the engineering demand parameter (EDP). The interdependency among bridge components is analyzed using regression correlation analysis to accurately estimate the seismic fragility of the overall bridge system. As a result, the fragility curve indicates that bridge damage, ranging from slight to extensive, has occurred within a minimum PGA interval and collapsed immediately after seismic events, with the extent of damage directly correlated with ground motion PGA. They have provided intriguing results for practicing structural engineers and decision-makers on Ethiopian bridges' seismic risk and vulnerability. Therefore, considering modest seismicity characteristics in highway bridge design and construction is crucial for assessing and controlling infrastructure collapse, avoiding seismic risk, repair costs, and recovery time.