Probabilistic Seismic Performance Assessment of RC Structures with Material and Geometric Uncertaities

Abstract

This study presents a probabilistic framework to evaluate the seismic risk of reinforced concrete (RC) buildings in the Koyna–Warna region by incorporating uncertainties in material properties, structural configuration, and seismic loading. Probabilistic collapse curves were developed to compare the influence of key parameters, and a detailed sensitivity analysis revealed that peak ground acceleration (PGA) is the most influential factor affecting collapse probability. Variations of ±20% in PGA resulted in a +45% to −40% change in collapse probability, followed by uncertainties in concrete strength and steel yield stress. Irregular buildings (B3) exhibited higher vulnerability to geometric uncertainties and showed lower median PGA values across all damage states compared to regular buildings (B1 and B2).Model validation against experimental drift ratios demonstrated good agreement, confirming the reliability of the probabilistic approach. Compared to deterministic methods, the probabilistic model provided a realistic range of outcomes and associated probabilities, enabling a more comprehensive assessment of seismic risk. Case studies further revealed that regular buildings perform better under seismic loading, while irregular configurations experience greater damage, especially at higher PGA levels (e.g., 0.5 g). Risk indices also indicated higher annual probabilities of exceedance for B3 relative to B1 and B2.Overall, the findings highlight the necessity of incorporating uncertainties into seismic design and assessment of RC buildings, particularly in seismically active regions such as Koyna–Warna. The proposed probabilistic methodology offers a robust tool for evaluating structural performance, guiding design decisions, retrofitting strategies, and supporting resilient urban infrastructure planning