Damage Characteristics and Seismic Performance of Post-2018 Reinforced Concrete Buildings: Field Evidence from the 2023 Kahramanmaraş Earthquakes

The Kahramanmaraş earthquakes on February 6, 2023, provided a unique field environment for evaluating and comparing the performance of reinforced concrete (RC) buildings constructed in different code periods. This study investigates the seismic damage characteristics of post-2018 reinforced concrete buildings constructed in accordance with the Turkish Building Earthquake Code (TBEC-2018) by comparing them with pre-1999 structures. Official post-earthquake damage assessment data collected from the provinces of Gaziantep, Kahramanmaraş, and Hatay were used. A core dataset of 120 post-2018 RC buildings with complete attributes was examined alongside 130 pre-1999 reference buildings. The buildings were classified according to the number of stories and damage levels, and statistical analyses and field observations were performed. The findings show that post-2018 buildings have significantly lower collapse rates compared to pre-1999 stock, but no homogeneous performance was observed within the group. Specifically, it was found that the failure rate increased significantly with the number of stories; this rate, which was 18.4% in 1-4-story buildings, reached 50.0% in buildings with nine or more stories. Observed failures were most frequently associated with structural irregularities and configuration-related asymmetries, including soft-story behavior, short-column effects, and overhanging upper stories. While TBEC-2018 improves overall collapse prevention capacity, structural configuration vulnerabilities and implementation deficiencies continue to elevate seismic risk in modern buildings.