Structural strengthening of 12-classroom type school buildings with fiber reinforced polymer (FRP) and cost-benefit analysis

Most existing school buildings were built between 1998-2005 using Ministry of National Education standard designs, but these structures may not meet current TBDY 2018 performance requirements. The February 6, 2023 Kahramanmaraş earthquakes highlighted the critical importance of school buildings and their urgent need for strengthening. This study analyzed 12-classroom reinforced concrete school buildings using 12 different scenarios with varying concrete strengths (C12, C16, C20), stirrup types, and steel reinforcement. Nonlinear pushover analyses were performed using ideCAD software, and results were compared with TBDY 2018 damage limits. Buildings that failed to meet performance targets were strengthened using hybrid methods combining concrete shear walls and FRP reinforcement. The hybrid strengthening approach significantly improved structural performance. Shear wall additions and FRP wrapping increased structural stiffness and load capacity by 30-50% on average. Story drifts and energy demands decreased by 25-40% at critical earthquake levels. Higher concrete grades (C20) with ribbed reinforcement provided over 40% additional strength improvement. All strengthened scenarios successfully met target performance levels. Cost-benefit analysis showed that FRP strengthening costs remained below 40% of reconstruction costs. Based on reports from L'Aquila (2009) and TBMM (2021), FRP applications offer advantages in labor, time, and maintenance. Results indicate that hybrid strengthening is more effective than reconstruction or concrete-only solutions in both structural and economic terms. This study provides guidance for practical, fast, and cost-effective strengthening methods to improve seismic safety of 12-classroom school buildings in Turkey. Keywords: FRP Composite Strengthening, RC Shear Wall Reinforcement, Seismic Performance Improvement