Retrofitting of Slender Masonry Arch Bridges

There is a large stock of masonry arch bridges built more than 100 years ago that are still in use in the world roadway and railway network. The restoration and conservation of this type of structures has become one of the main challenges of bridge engineering. As a first step, any intervention strategy requires an early stage consisting in the assessment of the structural safety (in the actual condition) of the masonry bridge. Only after that stage is performed, it is possible to design, if required, optimal repair interventions to bring the bridge to adequate safety level. In the first part of this paper, the seismic vulnerability assessment of a slender multi-span masonry arch bridge is presented. Results show that it is required to increase the flexural capacity of the structure. In the second part, an innovative intervention technique intended to increase the capacity of masonry arches is discussed. The proposed intervention technique consists on applying a layer of steel fiber reinforced mortar (SFRM) on the arch intrados. The behavior of a masonry arch strengthened with this technique is discussed by means of experimental and analytical results.