54 research outputs found
Finite Element Modelling of the Archaeological Colonnade in Pompeii
No full textIn this paper, the seismic behaviour of an archaeological monumental colonnade under earthquake actions is examined through planar numerical simulations (nonlinear finite element analyses). The colonnade has two storeys with multi-drum columns and multi-blocks segmented trabeations. The scope of the analyses is to improve the knowledge on the structural behaviour of the innovative solution of segmented trabeation adopted in the ancient era for this colonnade and to evaluate the added vulnerability related to the effects of water leakage and pollutants in between the stone blocks of the structure as a result of the current degradation.
The ancient city of Pompeii in Italy, is a partially buried Roman town-city; after suffering many earthquakes in the past it was destroyed during a long catastrophic eruption of the Vesuvius volcano in 79 A.D. and remained covered until its accidental rediscovery in 1749. Nowadays, the ruins of the ancient town present many partially collapsed buildings, not only as a result of other earthquakes during the last three centuries, but also as a consequence of rapid degradation of the archaeological material. Numerical analyses show the seismic vulnerability of a colonnade, in order to understand how a UNESCO World cultural heritage site can be preserved, avoiding risks for cultural heritage and human life
Restraining bars buckling by means of FRP wrapping: an analytical approach
No full textInternal transverse steel reinforcements (e.g. stirrups) are the main internal devices that avoid the longitudinal
steel bars buckling, but in most of all existing RC structures the quantity and the spacing between steel stirrups
are inadequate. In these structures longitudinal bars buckling can be avoided by applying external reinforcement,
in particular, by means of Fibre Reinforced Polymer (FRP) wrapping. A novel analytical approach for the study
of longitudinal bars buckling in column wrapped with FRP is proposed. longitudinal bars has been considered as
axially loaded beam, while the mechanical effect of FRP wrapping on the bars has been modelled by means of
springs. The effect of elastic and inelastic behaviour has been taken into account by means of the reduced
modulus theory. The well-known relations for steel stirrups has been extended to the case of FRP wrapping to
propose an analytical formulation, valid both for circular and noncircular column cross sections, for the
evaluation of the FRP thickness needed to avoid the longitudinal bars buckling
Experimental investigation of the seismic performances of IMG reinforcement on curved masonry elements
No full textIn recent years, several new materials and technologies have been developed to limit the effects of earthquakes on the structures. In particular, for the structural reinforcement of masonry elements, the use of composite materials has shown to be effective. The experimental results of an innovative reinforcement technique based on inorganic matrixes, namely Inorganic Matrix composite Grid (IMG) are herein presented. The reinforcement has been applied to a full-scale masonry vault. Several shaking table tests (before and after the IMG reinforcement application) have been performed. The structural performance of the vault has been evaluated comparing the damages detected in the case of unreinforced and reinforced specime
Evaluation of different computational modelling strategies for the analysis of low strength masonry structures
No full textMasonry is a composite material characterized by a large variability of its constituent materials. The materials used, the quality of the bond and variations in the standard of workmanship significantly affect the mechanical performance of the overall masonry structure. Masonry structures, especially the historical ones, are usually characterized by low strength, due to a variety of reasons, namely low units and/or mortar strength or low bond; this makes more difficult to study these types of structures according to general rules because of different structural schemes. The aim of this paper is to evaluate the suitability of continuous FEM (Finite Element Method) or discrete DEM (Distinct Element Method) approaches to analyse the behaviour of low strength masonry and to contribute to the knowledge and selection of the best approach with a cost and time effective solution. The comparison with experimental results on different low strength masonry validated the approaches and showed that, for low bond strength masonry, DEM approaches performed better compared to low unit strength masonry where the emphasis on joint behaviour in DEM approaches is less effective because the weak component is the unit
Metodologia per l'accertamento medico-legale dei risultati a distanza di discectomie lombari
No full text
Intracavernous giant fusiform aneurysm of the carotid artery treated with Gianturco coils.
No full textRinforzo di una volta in muratura: valutazione dell’efficacia mediante test su tavola vibrante
No full textLow unit strength masonry: computational modelling approaches
No full textMasonry is characterized by the large variability of its components. Parameters like strength, bond and workmanship defects strongly influence the performance of the overall structure. The applicability of different computational modelling approaches to assess the structural behaviour of masonry has been studied. Two of the most relevant computational modelling approaches have been considered namely: finite element method (FEM) and distinct element method (DEM). In order to validate the numerical outcomes, comparisons with the experimental results have been undertaken. The aim of this paper is to contribute to the knowledge and selection of a suitable modelling approach for modelling low unit strength masonry structures. The results showed that in the case of low unit strength masonry, FEM is a more suitable approach to use. In fact, since in the considered case, the block is the weak component, it is not possible to assume the brick units as a rigid block. Therefore an accurate plasticity and cracking model for the brick is required
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