Lateral strength and ductility of reinforced concrete columns strengthened with NSM FRP rebars and FRP jacket
Subject Areas : Structural Mechanics
Keywords: Reinforced concrete column · Near surface mounted (NSM) · Fiber, reinforced polymer (FRP) jacket · Flexural strengthening · Seismic performance,
Abstract :
Fiber-reinforced polymer (FRP) wrapping of reinforced concrete (RC) columns is an effective way to improve their shearcapacity and ductility and prevent buckling in their longitudinal reinforcements. Another strengthening method called the nearsurface mounted (NSM) reinforcement has been proven effective in improving the flexural strength of RC columns. In thisresearch, the strengthening of RC columns with the combined use of NSM rebars and FRP jacket was studied using a finiteelement modeling approach. After validating the numerical models with the existing experimental data, a comprehensiveparametric study was performed to determine the effect of axial load, implementing the FRP confinement around the base orover the entire height of the column, the number of plies of FRP jacket, the type of jacket fiber, the ratio of NSM reinforcement,and the compressive strength of the concrete on the behavior of the strengthened RC columns. The results show thatthe optimum number of plies of jacket for reaching a desirable level of ductility can be determined by setting the maximumcompressive strain in the confined concrete, ccu , to 0.008. Increasing the ratio of NSM reinforcement from 0.16% of the totalcross-sectional area to 1% led to approximately 28% increase in the lateral strength and 50% decrease in the ductility factor.