Vulnerability of masonry arches under increasing embrace displacements

Masonry arch systems and vaulted structures constitute a structural typology widely spread in the historical building heritage. Small displacements of the supports can lead this type of structures to a condition of collapse because of gradual changes in geometry. In the framework of the rigid in compression no tension model for the masonry material, this paper presents a tool for the computation of the magnitude of the displacements that can be sustained by the arch before reaching a collapse condition. The analysis of the collapse has been performed according to the approach of the kinematical theorem of the collapse state. For the case of the circular arch subject to dead loads, numerical analysis have been carried out by varying the main geometrical parameters in order to evaluate their influence on the maximum allowable displacement of the springing.