Importance of building inspection on the seismic response of a severely damaged RC structure during the February 6, 2023 Kahramanmaraş earthquake sequence

Abstract

Large magnitude February 6, 2023 earthquakes in Türkiye created a devastating effect on the building stock on a vast region. For earthquakes of this magnitude, severe damage and collapses are indispensable to the old building stock with deficiencies certified in previous earthquakes. But unexpectedly, the newly constructed buildings that were designed by recent version of Turkish Building Seismic Code (TBEC 2018) also experienced severe damage. After conducting site investigations on one of the recently constructed and severely damaged RC building, a detailed numerical study was performed to identify the reasons for the observed seismic damage. This study pinpoints the main cause of such damage due to lack of thorough building inspections during construction to ensure the implementation of the seismic reinforcement detailing specified in blueprints for providing required ductility, as revealed by field investigations. Additionally, it identifies potential issues stemming from a lack of full comprehension of the seismic design philosophy within the code. The existing design pushes the limits on the axial load level on slender column elements and fall short in capturing the soft story irregularity. Although there is a soft base story in the investigated building, using structural walls only in one direction with moderately confined boundary zones increased its vulnerability. This example shows that in Türkiye, where seismic activity is very high and quite lethal, seismic design codes should set stricter limits and measures, and building inspection system must be strictly enforced.