Empirical Fragility Curves for RC Residential Buildings after 2023 Kahramanmaraş, Türkiye Earthquakes

Abstract

A series of seismic events impacted southern Türkiye on February 6, 2023, causing substantial damage on building stock and infrastructure. The sequence comprised three distinct earthquakes with moment magnitudes (Mw) of 7.7, 6.6, and 7.6, occurring chronologically. Eleven cities endured a direct impact, resulting in the collapse or severe damage of thousands of buildings. Promptly following the events, government authorities initiated post-earthquake site inspections, with a substantial number of engineers contributing voluntarily to the reconnaissance effort. This collaborative effort yielded a valuable dataset encompassing various structural features and corresponding damage levels for each evaluated building. The current study aims to leverage this data to establish empirical fragility curves for reinforced concrete residential buildings in Türkiye. Buildings are classified into six construction year categories and three height classes (low-, mid-, and high-rise) formed based on regulatory transitions and observed similarities in construction characteristics. Fragility curves for eighteen building categories are derived using the Maximum Likelihood Estimation (MLE) technique. The results clearly indicate that newer buildings exhibit reduced seismic vulnerability, while mid- and high-rise buildings consistently demonstrate higher fragility across all construction periods. The developed fragility curves hold significant utility for risk assessment studies and rapid post-earthquake damage evaluations.