PROFESSOR F. SAWKO Sultan Qabos University, Oman.

A method of rehabilitation is described, designed to preserve the external appearance of masonry arch bridges while enhancing their load carrying capacity. The procedure consists of removal of overburden (and parapet walls if cracked or deformed) placing steel mesh reinforcement on the exposed extrados, fixing this to the existing arch rib, casting a concrete rib of minimum 150mm thickness and restoring the parapets and riding surface. The paper derives simple numerical procedures for estimating the need for strengthening and the strength enhancement achieved as a result of the procedure outlined above. This enhancement is due to two factors: the additional thickness of composite arch rib produced and the tensile strength of longitudinal reinforcement mesh incorporated within the body of new concrete.