Overlap length for confinement of carbon and glass FRP-jacketed concrete columns

This paper presents the experimental results of a study on the occurrence of debonding along the overlap length of fiber reinforced polymer (FRP) confined concrete prior to rupture of the FRP jacket. Plain concrete cylinders, twenty-six with 152 mm diameter and 305 mm height, and four with 100 mm diameter and 200 mm height, with cylinder compressive concrete strength 19 MPa, were wrapped with carbon- and glass-FRP jackets and tested under monotonic axial compression. Different overlap configurations and different FRP application methods were investigated. The parameters found to most significantly affect the bond resistance along the overlap zone are the type of the FRP material and the curing age of the resin when dry lay-up application is used.