A parsimonious discrete model for the seismic assessment of monumental structures

The evaluation of the nonlinear dynamic response of masonry monumental structures still represents a complex issue whose rigorous approach requires ad hoc computational strategies, difficult to apply to large structures hence unsuitable for practical applications. However, for the structural assessment of existing monumental structures engineers need robust and efficient numerical tools, whose complexity and computational demand should be suitable for practical purposes. For these reasons the formulation and validation of simplified numerical strategies constitutes an important research issue in masonry computational research. In this paper the computational performance of an original discrete element modelling approach, relying on the definition of a spatial macro element, for the simulation of both the in-plane and out-of-plane behaviour of masonry structures also in presence of curved geometry is investigated. The mechanical response of the element is governed by a discrete distribution of nonlinear links whose calibration follows straightforward fiber discretization. The approach may be defined as ‘parsimonious’ since the kinematics of the element is described by seven degrees of freedom only irrespectively of the number of the nonlinear links distributions that govern the constitutive response. The new macro-element has been implemented in the user-oriented software code HiStrA, which simplifies the modelling of historical structures by means of several wizard generation tools. The proposed model, representing a further tool for the structural assessment of historical masonry structures, is validated against numerical and experimental results involving typical masonry monumental sub-structural elements.