Seismic performance of retrofitted and non-retrofitted RC school buildings after the February 6th, 2023, Kahramanmaraş earthquakes

On February 6, 2023, two significant earthquakes struck Pazarcık and Elbistan/Kahramanmaraş with magnitudes of 7.7 and 7.6, respectively. These earthquakes are considered the most devastating disaster in Turkey in the last century. According to official records, these earthquakes affected 11 provinces, resulting in the loss of more than 50,000 lives. Additionally, numerous buildings collapsed or became unusable due to the impact of the earthquakes and the schools constitute an important part of these structures. The schools are important facilities that need to be functional and safe following an earthquake. This study contains both post-earthquake field observations and numerical studies for the retrofitted and non-retrofitted schools. It investigates the retrofitted and non-retrofitted conditions of a total of 7 blocks, which consist of 4 different schools located in Kahramanmaraş. It is observed that the retrofitted school buildings weren’t damaged after these earthquakes. The numerical models underwent nonlinear time history analyses using the ETABS program. The ground accelerations used in the analyses were obtained from the nearest station to the school buildings. The analyses yielded several results, including the natural periods, story displacements, story drifts, and seismic energy inputs of the structures. These results were then compared with the field observations to assess their accuracy and validity. With the retrofit application, story displacements, the interstory drifts and seismic energy input have decreased. Both field studies and numerical analyses have shown that even school buildings with insufficient material and engineering services can become resistant to major earthquakes with an appropriate retrofit method.