Behaviour of a masonry arch bridge repaired using fibre-reinforced polymer composites

This paper describes a series of laboratory tests investigating the behaviour of a large model masonry arch bridge repaired with externally bonded fibre-reinforced polymer (FRP) on its intrados. Many similar masonry arch bridges form critical links in the world's transport infrastructure, but they are often not suited to the increased demands of modern traffic loading, especially in ageing arch structures that have suffered structural deterioration. FRP plates, adhesively bonded to the intrados of the masonry arch are a convenient method for strengthening arch bridges. The tests described in this paper demonstrated that FRP strengthening is an effective technique for improving the structural performance of a masonry arch bridge.

A two-span, single-ring semi-circular brick arch bridge was tested in this study, complete with fill material. Each of the spans was initially loaded to investigate their response and to establish a four-hinge collapse mechanism, simulating damage prior to strengthening. FRP strengthening was then applied to the two arches, and each of the spans was again tested separately until the failure of the strengthening system. The global (load and deflection) and local (crack width and FRP strain) response of the structure was recorded. The FRP strengthening resisted flexural crack opening in the masonry, and hence prevented a four-hinge mechanism collapse. Failure instead occurred when the FRP strengthening debonded from the masonry adjacent to an existing intrados hinge crack. As well as shear debonding adjacent to flexural cracks in the masonry, peel debonding occurred where shear deformation occurred across a masonry crack. Catastrophic collapse did not occur, as the FRP continued to contribute to the load capacity by acting as a tie after the ultimate load had been reached. (C) 2011 Elsevier Ltd. All rights reserved.