Fragility analysis of tsunami resilient building for coastal regions of India

This study evaluates the tsunami fragility of Open Ground Storey (OGS) Reinforced Concrete (RC) buildings incorporating stepped column configurations to enhance structural stability, load-bearing capacity, and energy dissipation. Fragility curves for Immediate Occupancy (IO), Life Safety (LS), and Collapse Prevention (CP) states were developed using Monte Carlo Simulation (MCS) based on structural responses predicted by an Artificial Neural Network (ANN) model. The results show that stepped columns reduce inter-story drift by nearly 50 % and lower the probabilities of exceeding IO, LS, and CP states by 27.05 %, 28.57 %, and 32.4 %, respectively, compared to traditional RC designs, prevalent in the Indian coastal region. Sensitivity analysis, conducted after fragility assessment using Latin Hypercube Sampling (LHS) and Partial Rank Correlation Coefficient (PRCC) methods, identified concrete strength, steel yield strength, and column dimensions as key influencing parameters, with wave velocity becoming dominant at higher tsunami intensities. These findings demonstrate that stepped column designs with increased ground storey dimensions and optimized material properties offer a practical and effective strategy for enhancing tsunami resilience in coastal infrastructure.