Ricerc@Sapienza

This paper deals with the effects induced by the mechanized excavation of Rome metro line C in the area of an old masonry building, the Carducci school. Class A settlements predictions are obtained performing full 3D soil-tunnel-structure interaction numerical analyses, using a simple elastic perfectly plastic soil constitutive model.

Local damage models with softening needs localization limiters to preserve the mathematical
and physical consistency. In this paper we compare the properties of strain-gradient and
damage-gradient regularizations. Gradient-damage models introduce a quadratic dependency
of the dissipated energy on the gradient of the damage field and are nowadays extensively used
as phase-field approximation of brittle fracture. Their key feature is to provide a smeared
approximation of a crack as a band of localised damage with a finite energy dissipation per

A novel multiscale strategy is proposed for the damage analysis of masonry structures modeled as periodic composites. Such a computational strategy, whose aim is to reduce the typically high computational cost exhibited by fully microscopic numerical analyses, is based on a multiscale/multidomain model equipped with an adaptive capability, which allows to automatically zoom-in the zones incipiently affected by damage onset.

We prove the lower semicontinuity of functionals of a suitable integral form, arising in the variational
modelling of linearised elasto-plasticity coupled with damage and their lower semicontinuity is crucial in the proof of existence of quasi-static evolutions. This is the first result achieved for subcritical exponents γ < n.

Masonry is one of the most famous and widely used heterogeneous composite material, largely employed in historic and architectural buildings. Among the different approaches proposed to study masonry structural behavior, multi-scale procedures are modern and promising tools, representing a fair compromise between detailed description of masonry microstructure and computational burden. This work presents a multi-scale beam-to-beam model for the analysis of unreinforced and strengthened periodic masonry panels under out-of-plane loadings.

This paper presents a Timoshenko beam finite element for nonlinear analysis of planar masonry arches. Considering small displacement and strain assumption, the element governing equations are defined according to a force-based formulation that adopts three different parametrizations of the axis planar curve, permitting the exact description of the element geometry for arbitrarily curved arches. Specific quadrature techniques are illustrated to perform numerical integration over the curved axis.

This paper describes the simulation of RC members with a three-dimensional (3D), 2-node beam finite element (FE) that includes warping of the cross section. A previously proposed FE formulation is extended to allow the description of structural members with softening material behavior. The governing equations are derived from an extended four-field Hu-Washizu variational principle, with independent interpolation of the warping displacement field from the rigid section displacement, the generalized section deformation, and the material stress fields.

This paper presents the formulation of a tri-dimensional (3D) beam-column finite element (FE) with cross-section warping, based on a corotational approach for the analysis of damaging structures including material and geometric nonlinear effects. The model derives from an extended Hu–Washizu formulation and is an enhancement of a previously proposed beam FE formulation originally adopted for steel and reinforced concreted structures under linear geometry.

This paper presents two micromechanical and a multiscale finite element models for the analysis of masonry walls under out-of-plane instability effects. A two-dimensional modeling of the wall is considered in all approaches, assuming a cylindrical bending. The micromechanical analyses are performed considering elastic beams to model the bricks and either nonlinear beams or interfaces to model the mortar layers. The beam finite elements rely on the force-based formulation and account for large displacements by making use of the corotational approach.

Under horizontal loadings, such as seismic actions, buckling phenomena can strongly affect the bearing capacity of masonry walls to gravity loads. Indeed, due to the low tensile strength of the mortar, when vertically loaded masonry members are subjected to bending moments induced by load eccentricity, out-of-plane collapse mechanisms often prevail
on compressive vertical crushing. This work presents a two-dimensional micromechanical approach relying