Experimental/Analytical Study on Interfacial Fracture Energy and Fracture Propagation Along FRP-Concrete
I n t e r f a c e
Z. Wu, H. Yuan, H. Yoshizawa, and T. Kanakubo
Appears on pages(s):
bond strength; debonding and softening; effective bond
length; FRP laminates; interfacial fracture energy; load-carrying
The initiation and propagation of interfacial cracks along the FRP-concrete interface may affect the concrete cracking behavior, load-carrying capacities, and stiffness characteristics.. Moreover, fracture in the shear stress transfer region may also lead to brittle premature failures of FRP-strengthened structures. All these factors must be taken into account in structure strengthening design. In order to estimate and simulate the fracture behavior of FRP-strengthened concrete structures, some basic material and physical parameters such as interfacial fracture energy, local interfacial shear strength and effective bond length are determined by some fundamental experiments. In this paper, experimental program using single-lap shear test and double-lap shear test specimens are presented. The variables include different types and layers of FRP sheets, and different types of the concrete surface preparation prior to bonding. Also, nonlinear equations, derived for two typical local shear-deformation curves with and without softening behavior, are used to discuss the shear stress transfer and fracture propagation behavior by comparing with experimental results, Through these experimental/analytical results, the interfacial fracture energies and the local shear stress-relative displacement relationships are determined.