ABSTRACT
Through the variational method based on the Somigliana’s Double Dislocation, the theoretical elastoplastic solution of a masonry arch bridge is evaluated under a generic load condition, obtaining the live loads multiplier, which corresponds to the achievement of a predetermined ductility limit. The well-known experimental campaign performed by Schwartz e Thürlimann showed that the ultimate limit state of a masonry wall subjected to high eccentric compressive axial force is reached when there are high rotational capacity of the critical sections. From these results, the Swiss national standard proposed a ductility check at sectional level. In this work, the final configuration of the masonry bridges is evaluated considering the elastoplastic deformation of the structure obtained by the integration of the curvature that tends to infinity in the plastic-hinges sections and the rotations concentrate in the plastic-hinge sections necessary for the respect of the restrain conditions of the structure. Using this approach, a double ductility check is possible: at point and section level.
