ABSTRACT
Masonry arch bridges are long-lived structures that continue to form a vital part of our transport infrastructure. However, they are facing a number of challenges associated with their extended period in service and the changing requirements of modern transport systems. CIRIA C800 provides new, freely available, guidance for the assessment of masonry arch bridges, building on recent research findings and advice already available in existing CIRIA guidance and in UK highway and railway assessment codes. Most significantly, the new guidance promotes the use of the Permissible Limit State (PLS), the point beyond which progressive load-induced degradation occurs under service loads during the intended life of a bridge. This is designed to allow engineers to more reliably identify the bridges that are likely to be most susceptible to the damaging effects of repeated cyclic loading. Background information on the new guidance is presented in the paper, including details of a simplified PLS calculation method and an example that demonstrates how it can be applied in practice.
