Modelling of Debonding Failures in FRP-Strengthened Two-Way Slabs

Abstract

Synopsis: With the development of the technology of strengthening existing concrete structures using externally bonded FRP composites, a number of issues related to the structural behaviour of such structures require investigation. One of the most important issues is the interfacial behaviour between the FRP composite and the concrete as this often controls the failure mode of the strengthened member. Several studies have progressed on the development of appropriate interfacial behaviour (bond–slip) models and on understanding the debonding phenomena. This work focuses on the numerical modelling of FRP-strengthened two-way reinforced concrete slabs where the predominant mode of failure is debonding at the FRP-concrete interface. An appropriate finite element model that represents the interfacial behaviour for FRP-strengthened two-way slabs is presented. The proposed model successfully simulates the different flexural failure modes, particularly those related to the debonding of the FRP sheets. The ultimate load carrying capacity and load–deflection relationships are predicted with reasonable accuracy.