Seismic retrofitting techniques for masonry arch bridges

Masory arch bridges are an important part of both Italian cultural heritage and transportation network. Many of them have been built since the Roma age, and several of these bridges remain in service, despite having been subjected for centuries to a heavy regime of environmental conditions and loadings.Very few masonry arch bridges have been built in modern times, and knowledge of the related design methods is no longer part of a civil engineer's training. In the meantime, because of their fundamental role, it is frequently necessary to strengthen existing bridge or part of them. Recent advances in retrofit technology have extended the application of advanced rehabilitation, retrofitting, stregthnening and field monitoring technologies to ageing infrastructures, expecially in the case of structures in seismic areas. This paper deals with the reliability of these interventions, considering that several of these interventions, made in recent years, have shown their limits. Old masonry structures require specific approach: strengthening techniques must not be influenced by the load bearing capacity only, since historic structures contribute to a sustainable future. © 2010 Taylor & Francis Group, London.