A Case Study on Seismic Retrofitting of Sub-standard RC Buildings Using FRPS: A Building Damaged During 2023 Kahramanmaraş Earthquakes

Türkiye is located in a very active seismic region and experienced destructive earthquakes frequently in the last century. Despite the high-quality seismic design codes in force in Türkiye starting from 1940, construction without complying with these codes caused catastrophic consequences after every strong earthquake. Most recently, the 2023 Kahramanmaraş earthquakes revealed the poor seismic performance of sub-standard building stock in Türkiye once more. Seismic retrofitting has a critical role in risk reduction worldwide, considering its efficiency in terms of time and cost. Among strengthening alternatives, methods making use of FRPs come forward based on the superior characteristics of FRPs such as high strength, high durability, and lightweight. In this study, the seismic performance of a low-rise RC frame building damaged during the 2023 Kahramanmaraş earthquakes, which reflects the general characteristics of the sub-standard building stock in Türkiye with extremely low compressive strength of concrete, insufficient system rigidity, longitudinal reinforcement, confinement details, and cross-section dimensions of vertical RC elements, is evaluated. Then, to discuss the efficiency of structural strengthening using FRPs in reducing seismic risks of typical sub-standard buildings in Türkiye, the case building was hypothetically retrofitted at various levels of safety considering different intervention strategies. A nonlinear time history analysis with near station records is conducted, and the performance of the building is determined based on 2018 Turkish Building Earthquake Code. Finally, based on the results of this study, the effectiveness of considered intervention strategies is evaluated together with the seismic performance of the building observed after Kahramanmaraş earthquakes.