EXPERIMENTAL TESTS ON CONSOLIDATION OF MASONRY BRIDGES USING “ RAM-REINFORCED ARCH METHOD”

In the consolidation of masonry arch-bridges the best goal is to obtain a uniform compression between all the blocks, without addition of mass or changes to the actual geometry. The designer is asked to find structural solutions that are effective and respectful of the historical evidence, following the principle of “minimum intervention”. The paper describe an innovative technique, called "RAM - Reinforced Arch Method", for the consolidation of masonry arches through the placement of post-tensioned steel cables, either at the extrados of the arch or at the intrados. The method allows for reversibility, compatibility and re-tractability. The structural efficiency of the method was widely experimented. The tests, whose results are here illustrated, were conducted on more than 500 small scale models of different geometries ,varying the tension applied to the cables. The tests were oriented to verify the ability of the system to resist not only vertical forces but also horizontal loads, such as seismic ones. Full scale applications of the technique are illustrated, such as the stone masonry “Sogliano” bridge, over Rubicone river, in Italy.