Reinforced Concrete (RC) buildings designed for IS 456-2000 have been found to be weak in adequate seismic design provisions, capacity design considerations and detailing for ductile behaviour.
Experimental tests RC frames have shown that the excessive damage or failure of beam-column joints, in particular exterior (or corner) joints which can lead to the global collapse of a building. The poor joint behaviour of older construction can be attributed to the inadequate shear reinforcement in joint region and the deficient anchorage details into the joint region.
Recent evaluation of Civil Engineering structures has demonstrated that most of them will need major repairs in the near future. Up gradation to higher seismic zones of several cities and towns in the country has also necessitated in evolving new retrofitting strategies.
One of the techniques of strengthening the RC structural members is through confinement with a composite enclosure. This external confinement of concrete by high strength fibre reinforced polymer FRP materials such as basalt, glass and hybrid fibre, available today in the form of sheets, are being used to strengthen a variety of RC elements to enhance the flexural, shear and axial load bearing capacity of elements.
G. Maariappan & R. Singaravadivelan
Jeppiar Engineering College, India