Behaviour and modelling of FRP-to-concrete interfaces at elevated temperatures

FRP-strengthened reinforced concrete (RC) members in service are likely to experience elevated temperatures (i.e., thermal loading due to seasonal temperature changes or exposure to fire) besides mechanical loading. Such elevated temperatures have two different effects on the bond behaviour of FRP-to-concrete interfaces. The first effect is associated with the thermal stresses induced at the interface by the thermal incompatibility between FRP and concrete; the second effect associated with the bond degradation of FRP-to-concrete interfaces at elevated temperatures. This paper presents of a summary of recent research by the authors on these two issues. The work presented in the paper consists of two major parts: (1) analytical modelling of the bond behaviour of FRP-to-concrete interfaces under combined thermal and mechanical actions; and (2) formulation of a nonlinear local bond-slip model that describes the bond degradation of FRP-to-concrete interfaces at elevated temperatures.