Strengthening of reinforced concrete beams in flexure by partial jacketing

This work investigates the structural behaviour of reinforced concrete beams strengthened in bending by the addition of concrete and steel on their tension sides using expansion bolts as shear connectors, technique here denominated partial jacketing. The experimental program comprised tests on eight full-scale reinforced concrete beams, simply supported, with rectangular cross section (150 mm × 400 mm) and 4,500 mm length. Five of these beams were strengthened in bending by partial jacketing, while the other three did not receive any strengthening and served as reference beams. The flexural reinforcement ratio in the beams varied between 0.49% and 2.33% and the beams target concrete strength was 35 MPa. On the basis of the obtained test results, the studied strengthening technique proven to be efficient in terms of increasing the resistance and stiffness of the beams. The used expansion bolts as shear connectors proven to be practical and added ease to the application of this technique.