An analytical study on the shear strengthening performance of fire-damaged RC beams

Numerical models have been developed as alternative approaches to investigate the shear strengthening performance of fire-damaged RC beams but are still limited and require further investigation. This research study presented a simplified cross-sectional approach to evaluate and compare the shear strengthening performance of CFRP, steel plate, and concrete materials as potential options after fire exposure. This analytical approach was validated with previous experimental research to verify the validity of the method in evaluating the residual shear strength of fire-damaged RC beams. The results showed that the proposed method demonstrated good agreement in predicting the residual shear strength after fire exposure. A reference beam was selected and exposed to the ISO standard fire curve for 60 minutes and 120 minutes, respectively. Furthermore, each fire-damaged beam was retrofitted in shear with different configurations of strengthening matexrials to investigate the strengthening effect on shear strength recovery for each heating duration. The results showed that all strengthened beam models showed significantly improvements in stiffness, ultimate load, and deflection at ultimate load when compared with the control heated beams under both heating durations. CFRP was considered the best option due to its lighter weight and ease of installation compared to the other materials investigated.