Behaviour of rehabilitated RC beams with self-compacting concrete jacketing – Analytical model and test results

The use of thin reinforced self-compacting concrete jackets as a method to repair and strengthen under-designed flexural concrete members is investigated by means of experimental and analytical studies. The experimental component comprises 20 beam tests that were designed to fail mostly in shear either prior to, or immediately after flexural yielding with no ductility. After initial loading to near failure, specimens were repaired with three-sided jackets having the minimum thickness required in order to provide adequate bar cover and were subsequently retested to demonstrate the strength and ductility enhancement that could be attained through the intervention. The experimental results are correlated through member analysis considering the interfacial force transfer and relative slip occurring along the contact surface between new and existing concrete. The efficacy of the repair procedure and the important parameters controlling the post-repair response are highlighted through consistent evaluation of the confining action exerted by the jacket on the encased core using equilibrium of forces and a frictional model. It is shown that with proper anchorage, the repaired members approach the strength, ductility, deformation capacity and model of failure of the ideal monolithic member having identical reinforcement details.