Investigation of hysteretic response in FRP-retrofitted reinforced concrete columns through experimental and simulation approaches

초록

Fiber Reinforced Polymer (FRP) sheets are widely used for seismic strengthening of reinforced concrete (RC) columns; however, their effectiveness depends strongly on material configuration and confinement mechanism. This study investigates the hysteretic behavior of RC columns retrofitted with different aramid FRP systems through experimental testing and numerical simulation. The results show that FRP strengthening increases the peak load capacity by approximately 4.5-9.65% and enhances the displacement capacity by up to 47.89%, indicat ing significant improvement in ductility and energy dissipation. Among the investigated systems, the multilayer composite panel (MLCP) provides the highest ductility, while the unidirectional Aramid B system offers a balanced enhancement in strength and stiffness. Numerical simulations using the ZeusNL program show good agreement with the experimental results. The results also show good agreement with ACI-based predictions, indicating con sistency with current design provisions. The findings highlight that effective strengthening should focus on the critical region near the column base and use an appropriate number of layers to balance structural performance and practical efficiency.

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