External strengthening of continous RC beams with CFRP

The structural behaviour of reinforced beams strengthened in flexure with externally bonded FRP (Fibre Reinforced Polymer) reinforcement has been extensively investigated with respect to isostatic beams. Design methods are given in guidelines and standards, and failure modes are described. However, limited information is available on the behaviour of continuous beams, strengthened with composite reinforcement. For flexural strengthening of a 2-span continuous beam, the FRP reinforcement can be applied on top of the central support, at the bottom-side of the two spans or at both locations. By means of an analytical study, the non-linear behaviour of this type of beam is investigated. The failure modes are studied and it is verified to which degree moment redistribution is still present when applying this strengthening technique which makes use of a linear elastic polymeric material