Abstract

An efficient computational tool for the local failures analysis in historical masonry aggregates is proposed. A NURBS (Non-Uniform Rational B-Spline) representation of geometry is adopted. NURBS entities, which are common in commercial CAD packages, have the great advantage to describe complex geometries (such as curved elements and walls with a high number of holes) with very few elements. An upper bound limit analysis formulation is implemented, in which the adopted NURBS elements are idealized as rigid bodies with dissipation allowed only along interfaces. The mesh of NURBS elements is progressively adjusted through a genetic algorithm in order to minimize the live load multiplier. This procedure is applied in the evaluation of the horizontal load multiplier associated with the activation of local mechanisms during a seismic event. Some case studies, referring to masonry aggregates located in the historical centers of Arsita (Abruzzo region, Italy) and Sora (Lazio region, Italy), are here presented. A quick evaluation of the seismic vulnerability is performed through the presented NURBS-based computational tool, showing the high importance of the local response in the study of the seismic behavior of masonry aggregates.