Seismic Performance Analysis of RC Bridge Substructures using Pushover Method

Bridges serve as critical transportation infrastructure, yet many older reinforced concrete bridges lack adequate seismic design, leaving them vulnerable to moderate earthquakes due to insufficient shear capacity, poor confinement, and limited transverse reinforcement. In seismically active Bangladesh—a river-dense region with no bridge-specific seismic code—this study addresses the gap by integrating (BNBC, 2020) hazard data with (AASHTO, 2020) LRFD design provisions for bridge substructures. The research evaluates soil-structure interaction effects, particularly on soft soils, and assesses seismic performance under varying earthquake intensities. Results demonstrate that AASHTO-compliant designs, adapted with BNBC seismic parameters, meet safety objectives for bridge piers in Bangladesh, providing a validated framework for regions lacking localized codes. Future work should explore advanced soil modeling and nonlinear time-history analysis to further refine seismic resilience.