Daniele Baraldi

This work aims to study the compressive buckling and consequent blowup of jointed concrete pavements due to thermal rise. For this purpose, a simple and effective mixed FEM, originally introduced for performing static and buckling analyses of beams on elastic supports, is extended for performing a preliminary study of jointed concrete pavements. An elastic Euler–Bernoulli beam in frictionless and bilateral contact with an elastic support is considered. Three different elastic support models are assumed, namely a Winkler support, an elastic half-space (3D), and half-plane (2D). The transversal pavement joint or crack is modeled employing a hinge at the beam midpoint with nil rotational stiffness. Numerical tests are performed by determining critical loads and the corresponding modal shapes, with particular attention to the first minimum critical load related to pavement blowup. From a theoretical point of view, the results show that minimum critical loads converge to existing results in the case of Winkler support, whereas new results are obtained in the case of the 2D and 3D support types. Associated modal shapes have maximum upward displacements at the beam midpoint. The second and subsequent critical loads, together with the corresponding sinusoidal modal shapes, converge to existing results. From a practical point of view, minimum critical loads represent a lower bound for estimating axial forces due to thermal variation causing jointed pavement blowup.

This contribution shows the effectiveness of a simple mixed Finite Element Model (FEM) for simulating the mechanical behavior of structural Laminated Glass (LG) beams, by numerically reproducing several laboratory tests of small LG specimens taken from literature. The proposed mixed model adopts small displacements and Euler-Bernoulli beam hypotheses and assumes glass layers displacements and polymeric interlayer shear actions as independent fields. Numerical simulations show that such a simple model is able to correctly reproduce LG specimens’ initial stiffness and first peak strength and can be adopted for design purposes of LG elements at a larger scale

This is a preliminary study to assess the mechanical behavior of an elevator car frame made of steel components, through dynamic identification. Final element models considering different restraint conditions on element nodes are taken into account to evaluate how the whole performance of the structure is affected by local connections.

The innovative sustainable technology based on natural fabric-reinforced cementitious matrix (NFRCM) is analyzed for strengthening masonry. A new frontier for composite materials is proposed as an alternative to well-known traditional technologies used to improve the seismic behavior of buildings, such as the portuguese technique ‘gaiola pombalina’, the Italian ‘baraccata house’ and the turkish ‘himis house’. Preliminary sensitivity analysis is performed on NFRCM and ‘baraccata’ numerical models. Both technologies are numerically compared. From the experimental results of in-plane incremental load test carried out by CNR-Ivalsa a numerical model is calibrated by non-linear pushover analysis to evaluate the behavior of masonry wall strengthened with natural fibers. This paper demonstrates the effectiveness of NFRCM systems for strengthening masonry as: i) a non-invasive solution without significant thickness; ii) a sustainable technology; iii) an intervention involving the whole wall surface avoiding failure local mechanisms.

Abstract. Masonry strengthened with natural fabric-reinforced cementitious matrix (NFRCM-strengthened masonry) is investigated by updating an existing discrete element model. Masonry walls are modelled by rigid blocks and elastoplastic interfaces that are able to account for mortar joints and block cracking. The reinforcement is modelled in a simplified manner considering perfect adhesion between wall and reinforcement and by adopting further spring elements connecting block centres. The model is validated by comparing it with an existing FEM based on a multi-step homogenization, where reinforced masonry is considered as a whole. Both approaches are used for performing nonlinear pushover tests with an increasing shear action applied to unreinforced and reinforced panels. The updated discrete model turns out to be able to represent the strength increment given by the reinforcement, but it is less able to represent the corresponding ductility increment.