Seismic Resistance of Circular Columns Reinforced with Steel and GFRP

To address the issue of corrosion of steel in concrete structures, glass fiber reinforced polymer (GFRP) reinforcement is slowly gaining acceptability as a replacement of steel. This paper aims to evaluate the feasibility of using GFRP as internal lateral reinforcement in columns and presents the experimental results of seven circular columns that were tested under simulated earthquake forces which included constant axial load and cyclic lateral displacement excursions. In addition to the moment versus curvature response and shear versus deflection behavior, a number of ductility parameters related to curvature and displacement, and work and energy dissipation are used to evaluate the performance of specimens. Due to their linear elastic behavior until rupture at a strain of approximately 0.02, GFRP spirals provided continuous confinement to the columns, which displayed large deformability. The application of GFRP as lateral reinforcement in concrete columns minimizes the corrosion concerns and delivers a strong and ductile column response.