Strengthening Short Concrete Columns Using Longitudinally Bonded CFRP Laminates

Synopsis: This paper investigates the behavior of short concrete columns strengthened with externally bonded longitudinal carbon fiber-reinforced polymer (CFRP) laminates combined with transverse basalt fiber-reinforced polymer (BFRP) wraps. A total of eighteen 500 mm-long [19.69 in-long] concrete column specimens with a square cross section (150 mm [5.91 in] width) were tested with different longitudinal and transverse reinforcement combinations under concentric and eccentric axial loadings. For eccentric loading, three end eccentricity to width ratios of 0.1, 0.2, and 0.3 were applied symmetrically at both ends of each simply supported column specimen to provide single curvature condition. The compressive longitudinal CFRP strips, in average, experienced 38% of their tensile rupture strain. The experimental results showed debonding of longitudinal CFRP laminates from concrete surface and buckling of bonded specimens as the dominant mode of failure, and revealed that transverse wrapping system is efficient in postponing the buckling/debonding failure.