Near-fault ground motion characteristics and its effects on a collapsed reinforced concrete structure in Hatay during the February 6, 2023 Mw7.8 Kahramanmaras, earthquake

Ground motion in the vicinity of fault rupture produces pulse-type loading that may impose severe lateral displacement demands on structures due to forward-directivity effects. The Mw7.8 Kahramanmaras, Earthquake on February 6, 2023 created very high amplitude ground motions in the city of Hatay with distinct near-fault characteristics. In the city of 400,000 inhabitants, 33 % of the building stock was severely damaged or collapsed. Among the collapsed buildings, it was observed that there were new buildings built according to the latest seismic regulations. The seismic characteristics of the ground motion in Hatay were examined, the fault rupture, ground conditions and earthquake source characteristics affecting the engineering demand parameters were determined. Then, the seismic behavior and the reasons for the collapse of a 13-story reinforced concrete building, which is thought to be earthquake resistant with its structural system and material quality, were investigated using acceleration time-series recorded at a station very close to the building location. It has been understood that in shear wall systems, wall position and seismic detailing can impart significant damage (total destruction) on these elements under the effect of large displacement and high axial load demand by limiting the required ductility. Wall boundaries require more stringent confinement detailing than stated by the code under near-fault effects.