Multistage Evaluation of Strengthening Strategies for Achieving Adequate Seismic Performance in Reinforced Concrete School Buildings

Abstract

It is crucial that socially important structures, such as schools, remain operational without sustaining damage after earthquakes. However, some public buildings in Turkey have not received adequate engineering services, making it necessary to evaluate the seismic performance of these structures and apply appropriate strengthening methods when deemed necessary. This study comprehensively examines potential strengthening strategies and their effects on various school buildings in Turkiye, a country located in a highly active seismic zone with a vulnerable public building stock. Three commonly used school building types (8, 14, and 22 classrooms) were selected. Parametric studies were conducted on buildings with insufficient seismic performance, evaluating different strengthening scenarios. Input parameters included varying peak ground acceleration (PGA) values reflecting regional seismicity, diverse local soil conditions, and different material strengths. Strengthening strategies such as reinforced concrete jacketing, shear wall addition and FRP wrapping were applied to columns. A total of 432 structural models were analyzed. One or more of these methods were used to achieve the target performance level. Results were interpreted based on structural strength, period, over-strength factor and cost. It was found that the combination of shear wall addition and jacketing had the most significant impact on structural period, leading to notable reductions in spectral displacement demands. However, this combination also resulted in higher over-strength factors and increased strengthening costs compared to other methods. The study concludes that the absence of over-strength targets for retrofitted buildings in seismic codes is a critical gap and should be addressed in future code revisions.