3rd Croatian Conference on Earthquake Engineering 3CroCEE

This study presents a comprehensive analysis of strong ground motion data acquired to better explain the extensive damage observed after the February 6th, 2023, Kahramanmaras, SE Turkey earthquakes (Mw 7.8 and Mw 7.6). As spectrum intensity values computed using response spectra of a ground motion are closely correlated with building damage, special emphasis is given on some engineering intensities of these records. As such, peak ground acceleration (PGA), peak ground velocity (PGV), peak ground displacement (PGD), efficient duration, Arias intensity (Ia) and Housner’s spectrum intensity (SI) are obtained and compared with the past earthquakes occurred in or nearby Turkey. Additionally, selected acceleration-displacement response spectra and inelastic earthquake spectra are generated for various damping ratios and ductility levels (µ=1~8) for several cities that were primarily affected by the earthquakes.
The spectral values are compared with the design earthquake spectra provided by the both past (after 1975) and current Seismic Codes. Particularly, in regions where reports of widespread building damage was prevalent, this comparison revealed substantial discrepancies between the demand and code-based design spectra.
Numerical results indicate that since the recorded ground accelerations are far beyond the recommended ones proposed in the Turkey Building Earthquake Code (TBEC, 2018), higher seismic demands are obtained particularly for buildings with a fundamental period range until 2 seconds. Poor soil conditions contributed to damage by magnifying the seismic demands. The recorded peak accelerations were considerably high, resulting in severe structural damage, particularly in RC buildings with substandard columns (i.e. with high axial load and shear demand) and in masonry buildings (both historic and non-historic). Inelastic response spectra of buildings with shorter periods showed large fluctuations, suggesting that these structures were subjected to severe shaking. Computed spectrum intensities for some stations are multiple times larger than the ones calculated for the past earthquakes, justifying such huge devastation.
Keywords: Turkey Earthquake Doublet, Strong Ground Motion Characteristics, Inelastic response spectra