Issue 43

P. Zampieri et alii, Frattura ed Integrità Strutturale, 43 (2018) 182-190; DOI: 10.3221/IGF-ESIS.43.14 184 condition defines the positions (X 1,0 ; Y 1,0 ) (X 2,0 ; Y 2,0 ) (X 3,0 ; Y 3,0 ) of the three hinges of the collapse mechanism in the initial configuration Ω 0 corresponding (ideally) to zero settlement of the movable springing and the minimum reaction force R α ,0 . Subsequently, it is possible to apply a generic displacement d k of the movable springing along a generic direction at the initial condition Ω 0 and then reapply PVW to the new deformed configuration Ω k (the subscript k refers to the k-th increment of displacement d k ) in order to determine the updated value R α,k of the reaction force in the α direction. Then a new thrust line is defined, verifying whether the solution sought is statically and kinematically admissible (that is, the thrust line is contained within the form of the arch and is tangential to the edge at the hinge points). Figure 1 : Virtual displacement diagrams in the initial configuration of the masonry arch. Figure 2 : Representation of the kinematic mechanism in the generic configuration displaced by Ω k . Figure 3 : Condition in which the hinges calculated in the k-1-th iteration do not coincide with the hinges in the k-th iteration