Title: FE Analysis on Cohesive Debonding and Cracking Behavior for HIP-Strengthened Concrete Beams by Nonlinear Fracture Mechanics
Author(s): J. Yin, Z. Wu, and T. Asakura
Publication: Symposium Paper
Appears on pages(s): 267-276
Keywords: cracking distribution; debonding; flexural crack; FRP-strengthened
beams; interfacial fracture energy; stress transfer
Experiments of three kinds of FRP-strengthened concrete beams under three-point bending are reviewed first. Two different cracking behaviors, with and without distributed crack in concrete, were observed. To analyze the different cracking behaviors affected by the FRP strengthening through interfacial bond, the FRP strengthened concrete beam is subdivided into a plain concrete beam, under three-point bending, and a FRP sheets bonded concrete prism, subjected to shearing load, to address the fracture mechanism. Nonlinear fracture mechanics is used to model the cohesive crack along the FRP-concrete bond interface and concrete cracking. Finite element simulation is also performed to demonstrate the applicability of the fracture mechanism. Based on both experimental observations and finite element results, it can be concluded that the FRP strengthening effect occurs after the first flexural crack. The bond strength and interfacial fracture energy of bond interface determine the ability of stress transfer. The occurrence of the new flexural cracks after the first one is governed by the relation between the concrete tensile strength and the maximum concrete stress obtained by combining effects of shear stress transfer and bending moment including the stress release due to flexural cracks. Further strengthening effect is archived by the formation of new cracks.