Future Directions in Seismic Design, Assessment, and Construction Practices: Insights from the February 2023 Türkiye Earthquake Sequence

In February 2023, Türkiye experienced a series of earthquakes that had a profound impact on 11 provinces, affecting a population of over 14 million. These seismic events caused an extensive devastation, resulting in moderate or further damage (heavy damage, collapse) of approximately 325,000 structures. Subsequent reconnaissance investigations revealed that there were structural inadequacies similar to those observed in previous seismic events, including improper arrangement of structural systems, poor quality of construction materials and insufficient reinforcement detailing leading to insufficient stiffness, ductility and strength. Notably, besides these shortcomings, it was observed that several newer medium-rise buildings (8-12 stories) underwent heavy damages and collapses. In some cases, such new mid-rise buildings exhibited a complete overturning due to heavy damages of structural members at the first story, whereas in some other cases pancake-type collapses were observed, as was commonly seen after previous earthquakes in Türkiye. This study provides insights into seismic design, assessment, and construction practices in the light of observations made in the aftermath of the Kahramanmaraş earthquakes. Furthermore, it was observed that the spectral accelerations calculated from measured strong ground motions were significantly higher than the elastic design spectral accelerations at some stations along certain ranges of periods. Therefore, the paper also initiates discussions on why numerous buildings, despite being subjected to substantial demands for strength and ductility, did not collapse, where many others collapsed under much smaller ground motions. The paper also presents recommendations for retrofitting of existing buildings targeting lower seismic performance levels and cost-effective solutions to mitigate against collapse. Finally, future directions for improving the seismic resilience of both new and existing buildings through advanced design methodologies and innovative technologies, including low-damage structural and non-structural systems are also explored to achieve a more resilient built environment.