International Institute for FRP in Construction
Proceedings of the 2013 Asia-Pacific Conference on FRP in Structures (APFIS 2013)
One of the most common failure modes of strengthened RC beams with externally bonded FRP is intermediate crack (IC) debonding of FRP initiated at the tip of flexural/shear cracks. This study presents a method, using extended finite element method (XFEM), to model IC debonding in an FRP-strengthened concrete beam. In XFEM, as soon as a damage initiation criterion is reached in an element, additional degrees of element freedom are added to model crack initiation. Crack propagation is then modeled using fracture energy criterion. This method can be used to simulate debonding failure along an arbitrary, solution-dependent path without the requirement of remeshing. The numerical results are validated against experimental data and good agreement is found. A sensitivity analysis is conducted to study the effects of damage band properties and geometry on FRP debonding failure. This verifies that shear strength and critical mode II fracture energy are the parameters most affecting the FRP debonding model when the crack tip is subjected to mode II loading.