Analisi di archi in muratura su imposte cedevoli

This paper deals with a method of analysis finalized to the study of limit condition of equilibrium in masonry arches subject to external inelastic displacements of abutments. In order to define the level of vulnerability in a masonry arch, which is in equilibrium in its initial configuration with respect to any load condition, it is considered significant for the establishment of the limit value of external displacement that can be assigned at one or both the abutments after which the structure collapses, assuming a modified geometrical configuration and therefore not more capable of withstand the initial load. The arch is modelled by a system of rigid elements connected to each other and to the external abutments by sections of interface characterized by a rigid – cracking behaviour contact constraint with respect to the internal actions that are transmitted perpendicular to the interface itself, and perfectly rigid with respect to shear forces. The constitutive model of the contact constraint is thus based on no-tension hypotheses, according to J. Heyman, with no tensile strength and infinite strength both respect to compression and shear interactions.