Numerical Stress Analysis of the Bond between a Reinforced Concrete T-Beam and FRP Sheets

Three-dimensional non-linear elastic finite element analysis models of a concrete beam strengthened with fiber-reinforced plastic composites have been developed. The results contribute to a fundamental understanding of the stresses and strains that occur at the interface between the composite overlay and the concrete substrate. How the presence of interface cracks affects the stress state along the bond between the FRP overlay and concrete substrate is investigated. Increased composite stiffness increases the interface shear stress and the energy release rate G at the interface crack tip. The load mode that occurs in the beam is mostly Mode II or mixed Mode I/Mode II loading.