ABSTRACT
Various methods have been studied in recent years to adhesive-bond carbon-fiber-reinforced polymer (CFRP) plate as a repair and reinforcement measure for steel structures. A patch plate requires as much bonding length as possible in addition to the damaged section targeted to transmit stress fully. It is possible to shorten the bonding length by thinning the adhesive layer, but the problem is that the CFRP plate is apt to peel if the adhesive layer is thin. Past studies investigated patch plate adhesive with an adhesive thickness of roughly 0.2 mm or more. It is thought to be difficult to use patch plate repair to ensure sufficient bonding length in confined places.
In this study, local repair was assumed, and, to shorten the bonding length and reduce the patch plate size, static tension tests of steel plates bonded to CFRP plates were performed, varying the adhesive-layer thickness. The focus was on the distribution of stress produced at the ends of the CFRP plate when tensile stress acted on the steel plate. It was confirmed that, when adhesive-layer thickness is very thin, the stress in a steel plate cannot be sufficiently reduced with the bonding length found from a theoretical formula.
Test pieces were modeled using Abaqus multipurpose finite-element method analysis, and linear elastic analysis was performed while varying the adhesive-layer thickness. When the stress generated in the CFRP plate was examined, the analysis results tended to conform roughly to experimental results. However, differences in the stress in the center of the thickness of a steel plate at the composite became larger as the adhesive layer became thinner.
