Effect on RC buildings of 6 February 2023 Turkey earthquake doublets and new doctrines for seismic design

Abstract

Two major catastrophic earthquakes, which occurred 9 h apart on the Eastern Anatolian Fault Zone and one of its branches on February 6, 2023 in Turkey, directly affected 11 provinces in the Eastern and South-Eastern Anatolia regions, where 14 million people live. These earthquakes are among the most destructive earthquakes in the history of Turkey, caused approximately 3 times more property damage and loss of life than the 1999 Marmara Earthquake. More than 24,000 aftershocks with magnitudes of up to 6.7 Mw occurred after these earthquakes. In this study, the causes of heavy destruction in some of the provinces and districts most affected by earthquakes (especially Hatay-Antakya, Kahramanmaraş, Gaziantep-Nurdagi, Gaziantep-Islahiye, Adıyaman-Gölbaşı, Malatya) were examined under sub-headings. The reasons for the damages were supported by the striking images obtained during the site investigation in the earthquake zone, and the issues that should be considered based on both seismic codes and implementations were also stated. In addition, in order to better understand the effects of earthquakes on reinforced concrete structures, the ratios of the loads acting on the structures in both earthquakes to the design load predicted by the code valid at the time the structures were built are presented in graphics. The results obtained show that the effects of design and application mistakes are quite high in the heavy destruction caused by earthquakes. But it is understood that the seismic code design criteria and requirements are insufficient in some regions. In addition, the establishment of residential areas in risky areas without taking any precautions has produced dramatic results.