Multidisciplinary reconnaissance investigation covering structural, geotechnical, and architectural based damage to mid-rise residential buildings following the February 6th, 2023 Kahramanmaraş, Türkiye earthquake doublets (M_w 7.8, M_w 7.6)

Kahramanmaraş and its surroundings were devastated with major earthquake doublets of M_w = 7.8 Pazarcık and M_w = 7.6 Elbistan/Ekinözü on February 6th, 2023. While a wide scatter of reinforced concrete (RC) structures experienced damage, mid-rise residential buildings constitute a large bulk with heavy damage or total collapse. Among many reasons, poor concrete strength and brittle fracture of rebars along with liquefaction-caused soil deformations contributed to building damage. This paper investigates structural, geotechnical, and architectural conditions of mid-rise RC residential buildings with heavy damage. The geotechnical component includes the investigation of liquefaction-caused settlement and subsidence of loose foundation soils. Architectural reconnaissance suggests that commonly encountered design mistakes observed in past earthquakes were repeated. Field investigation concludes that loose saturated silty and sandy soils exhibit liquefaction leading to permanent damage on the mid-rise buildings while tunnel-form code-designed RC buildings with seven-to-ten stories performed well.