Damaged masonry arch bridges strengthened with external post-tensioning: Experimental and numerical results

This paper deals with the structural performance and strengthening of damaged masonry arch models representative of two longitudinal sections typical of existing single-span masonry railway bridges. The two masonry arch models were tested in laboratory under loading-unloading cycles of increasing vertical loads applied at 26% of the net span. The arch models previously damaged by imposing loading-unloading histories were tested in the strengthened condition. The strengthening used is an external post-tensioning system composed of two cables anchored to the arch intrados. Experimental results have shown an increase in the bearing capacity and ductility of the arch models after the application of the post-tension. Finally, the results obtained from the experimental campaign have been compared with the numerical ones, obtained by implementing a rigid-block analysis.