Modelling the behaviour of RC beams retrofitted with CARDIFRC®

A new retrofitting technique based on a material (CARDIFRC®) compatible with concrete has been developed at Cardiff University. It overcomes some of the problems associated with the current techniques based on externally bonded steel plates and FRP (fibre-reinforced polymer) laminates which are due to the mismatch of their tensile strength and stiffness with that of the concrete structure being retrofitted. CARDIFRC ® is characterised by high tensile/flexural strength and high energy-absorption capacity (i.e. ductility). The special characteristics of CARDIFRC ® make it particularly suitable for repair, remedial and upgrading activities (i.e. retrofitting) of existing concrete structures. It has been shown that damaged reinforced concrete beams can be successfully strengthened and rehabilitated in a variety of different retrofit configurations using pre-cast CARDIFRC ® strips adhesively bonded to the prepared surfaces of the damaged beams. To predict the moment resistance of the beams retrofitted in this manner two analytical models are described in the present paper. The results of the analytical models are found to be in very good agreement with the test results.