Interface bond between FRP sheets and concrete substrates: properties, numerical modeling and roles in member behaviour

Abstract

SUMMARYThe success of most of strengthening or retrofitting technologies for concrete structures by using external bonded FRP sheets highly depends on the interface bond between FRP sheets and concrete substrates. This paper reviews current studies on evaluating the bond properties of FRP sheet-concrete interfaces, and in particular, focuses on several newly developed bond models for describing the bond characteristics of FRP sheet-concrete interfaces under various loading conditions. This paper also gives several examples that apply those interfacial bond models to the design of different retrofitting cases. Analytical solutions are discussed that consider the local interfacial delamination and slip behaviour, which can improve the prediction of strength and deformation performances, as well as clarify the failure mechanisms of concrete members upgraded with FRP composites. Moreover, the improvement in structural performances of retrofitted concrete members is discussed by relating them to the optimum microscopic properties of the interface bond and the properties of retrofitting materials.

Shear-Resisting Mechanisms of Pre-Tensioned Pc Beams Without Shear Reinforcement Strengthened by CFRP Sheets

“…For the bonded FRP sheets, the bond stresses developed within a certain length known as the effective bond length 22) . The previous studies 23), 24) have reported that the increase in the stiffness of the sheets resulted in the greater effective bond length. When the debonding of the sheets initiated, the effective bond length shifted to the nearby inactive bond zone until the debonding progressed completely 9), 25) .…”

A Review of Direct Shear Testing Configurations for Bond between Fiber-Reinforced Polymer Sheets on Concrete and Masonry Substrates

“…1 (a) and Fig. 1(d), are the most commonly used test methods among researchers because of their simplicity [4,[37][38][39][40][41][42]. However, the state of stress in the concrete in each of these two test methods can be expected to be quite different.…”

Review on Defects in GFRP Composites

“…The lifting of bonded sheet can simulate the interface defects that can be induced during bonding construction is classified as spalling defect [13]. When spalling takes place definite shear crack appears in flexural structures, the spalling part and the unspalling part lie in different curved surfaces [14].…”