New Life for Old Masonry Arch Bridges

Where road schemes require an alteration to alignment, width, or barrier containment standards on an existing bridge, the problems associated with achieving this are often significant. Records for bridges built more than 50 years ago are commonly incomplete. It is often easier to build a new independent structure to avoid these problems, particularly where a bridge is of significant heritage value. However, there are some well-documented alternatives to bridge replacement, which may be considered. A recent study of a heritage listed multispan stone arch bridge in Victoria explored the potential benefits of introducing a carefully detailed structural addition to the bridge in order to achieve the project requirements. In considering a modification to an existing stone arch bridge, it is essential to also bring the condition of the stonework up to a standard that can carry the new loadings over the proposed residual design life of the bridge. A suitable method for the rehabilitation of the arch barrel to restore the original joint integrity is also described.