Strong ground motion and structural damage in the 2023 Kahramanmaraş earthquakes: A comparative case study of numerical predictions and field observations

Abstract

On February 6, 2023, southeastern Türkiye was struck by two catastrophic earthquakes (Mw: 7.7 and Mw: 7.6) along the East Anatolian Fault Zone, causing extensive structural failures and significant loss of life. This study evaluates the seismotectonic characteristics of the sequence, analyzes strong ground motion data against the Turkish Building Earthquake Code (TBEC-2018) design spectra, and investigates the correlation between numerical performance predictions and observed field damage of a reinforced concrete building in Kırıkhan/Hatay. Ground motion data from affected provinces demonstrated peak ground accelerations exceeding code expectations by up to five times, particularly in areas with soft alluvial soils, amplifying seismic demands through site effects and near-fault phenomena. A core contribution of this research is the detailed structural evaluation of a representative reinforced concrete building subjected to these extreme demands, incorporating experimental concrete compressive strengths derived from material tests and field-verified reinforcement layouts. While nonlinear static assessments executed via macro-level modeling tools successfully predicted global stability and “Collapse Prevention” status under DD-1 and DD-2 hazard levels, they failed to capture the brittle shear failures observed in short coupling beams and shear wall boundary elements. This divergence stems from the models' tendency to idealize ductile flexural response, overlooking localized brittle triggers exacerbated by poor workmanship, inadequate transverse reinforcement, and reinforcement debonding. These findings demonstrate that while macro-level modeling effectively evaluates global structural safety, it must be coupled with shear-sensitive formulations and localized damage criteria to accurately capture actual structural capacity during extreme seismic events.