Investigation of the Effect of FRP Fibers on the Seismic Retrofit of Reinforced Concrete Flat-Slab Frames with Openings under Cyclic Loading

Flat slab systems are susceptible to brittle punching shear failure at slab–column connections, which may trigger progressive collapse. This study aims to evaluate and compare the effectiveness of fiber-reinforced polymer (FRP) strengthening with conventional concrete and steel jacketing techniques in enhancing the punching shear performance of reinforced concrete flat slabs. A five-story reinforced concrete building with a flat slab system was designed using ETABS and subsequently modeled in ABAQUS for detailed finite element analysis. Three retrofit scenarios, including FRP strengthening, concrete jacketing, and steel jacketing, were numerically investigated and compared in terms of load-carrying capacity, deformation response, and failure behavior at slab–column connections. The results indicate that FRP strengthening significantly improves punching shear resistance and stiffness while providing higher energy absorption capacity compared to the other techniques. In contrast, concrete and steel jacketing increase structural weight and exhibit less efficient performance enhancement. Overall, FRP strengthening demonstrated superior efficiency in improving structural safety and mitigating punching shear failure in flat slab systems, highlighting its practicality as an effective retrofit solution.

کلیدواژه ها:

cyclic loading ، Reinforced concrete frame ، Retrofit ، Flat slab ، finite element analysis