Correlation of seismic demand and performance for severely damaged low-rise buildings during the February 2023 Kahramanmaras, Turkiye earthquake sequence

Abstract

This study investigates the structural characteristics and seismic demand-performance correlation for low-rise buildings that sustained severe damage during the February 2023 Kahramanmaras,, Turkiye, earthquake sequence. The research focuses on the Islahiye district of Gaziantep Province, which was heavily impacted due to its proximity to the fault line and exposure to two major earthquake events (M7.7 and M6.6) which occurred within 11 min. The study uses data from 1778 severely damaged low-rise buildings constructed using reinforced concrete (RC), masonry, steel, and prefabricated technologies. First, a comprehensive evaluation of the seismological setting of Islahiye and the characteristics of the recorded strong ground motions is presented. Next, post-earthquake surveys of severely damaged low-rise buildings are analyzed with consideration of structural system type, construction date, occupancy type, and number of storeys. Subsequently, the observed damage patterns in masonry and RC buildings are evaluated in accordance with Turkish seismic design codes. Finally, the seismic demand-performance correlations under the sequential impacts of the M7.7 and M6.6 earthquakes are investigated by considering fundamental periods, Sa-Sd spectral capacity curves, linear and nonlinear acceleration response spectra, and linear and nonlinear energy response spectra and history diagrams including various energy components. The results indicate that the fundamental periods of the damaged buildings are closely aligned with the spectral and peak response characteristics of the recorded ground motions, leading to resonance effects. Furthermore, the sequential nature of seismic actions significantly amplified cumulative damage, especially in buildings characterized by low ductility, inadequate detailing, and substandard construction quality.