Effect of FRP and radial-pin reinforcement on the modes of failure and fatigue performance of multi-ring masonry arches

Over 60% of European masonry arch bridges are more than 100 years old and many of them need repair and strengthening. Current techniques involve the introduction of some form of reinforcement into or on the masonry arch barrel. There has been limited number of tests carried out on performance of strengthening techniques, most of them under static or small number of cyclic loading. There is therefore increasing need for an independent review of the efficiency of such strengthening techniques and of their long term performance. A series of 3m and 5m span multi-ring masonry arches tests have been carried out at the University of Salford under long-term cyclic loading to investigate the efficacy of FRP reinforcement at the intrados and radial pinning. It has been found that although the presence of the FRP sheet increased the load capacity under cyclic loading, it also reduced the static load capacity of some arches by changing their mode of failure and thus weakening the arch. Radial pin reinforcement together with FRP strengthening seemed to reinstate and improve the original load capacity of the arch. Possible forms of failure mechanisms for pin reinforcement were presented together with a practical guide for quantifying the number of required radial pins. For the covering abstract see ITRD E126028.