The technique of flexural strengthening of reinforced concrete structures using externally bonded composite reinforcement has been in use since the mid 1990’s. The method of strengthening by bonding steel plate, which had been used in the UK since 1975, has now generally been replaced by the use of composite plates.
The increased acceptance of the method has led to different types of structure and problems being considered for strengthening using composite materials. The flexural capacity of metallic structures such as cast iron and steel can be improved. The resistance of reinforced concrete or masonry against impact, blast and seismic loads can be increased. Reinforced concrete structures deficient in shear can be strengthened. The use of pre-stressed composite plates can relieved both dead and live loads at the same time as overcoming difficult detailing problems.
The success of any new techniques depends on detailed research and development and the long term durability of all the materials used in the strengthening system. The other main system components that should be included in this development are the adhesives used to bond the composite to the structure.