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Venezia, Italy

Università Iuav di Venezia is a university in Venice, Italy. It was founded in 1926 and has 3 departments. Wikipedia.

Russo S.,IUAV University of Venice
Composite Structures

This study shows a procedure for the identification of the mechanical characteristics and dynamic parameters of glass fiber-reinforced polymer (FRP) pultruded elements. The matching between analytical model and experimentally acquired modal and natural frequency data is used to investigate the homogeneity of materials (resin and fibers) and the mechanical characteristics variation for pultruded profile with different cross sections, also in presence of induced damage. The experimental results are given primacy, and then the model must be modified by trial and error methodologies of model updating approach. This work depicts the sensitivity analysis based FE model updating procedure and its application to mechanical characteristics and damage assessment of different GFRP members from modal parameters. The accuracy analysis, that relies upon the relative confidence between the results (exp. and analytical) features a FE model of pultruded composite profiles with orthotropic behavior. The same structures were subjected to damage and their identification is based on dynamic response through the curvature mode shapes. This approach allows to know the location and size of damage, the change in dynamic characteristics and thus the decrease in strength and stiffness. The damage identification was carried out also with FE analysis by updating the undamaged beam model. © 2012 Elsevier Ltd. Source

Foraboschi P.,IUAV University of Venice
Composites Part B: Engineering

The subject of this paper is the plate composed of two identical layers connected to each other in a discontinuous way, i.e. via discontinuous elements (connectors). This paper presents a model that describes the mechanical behavior of this plate by a system of exact, analytical (explicit) equations. The discrete distribution of discontinuous connectors is replaced by a fictitious continuous medium (interlayer). Accordingly, the plate is modeled as an equivalent three-layered plate: Two outer layers and a connecting inner interlayer. In order to obtain a fast and easy to use tool, something that is necessary for an analytical model to be chosen over finite elements and empirical formulas, modeling process is developed within the framework of two-dimensional elasticity. In so doing, the model also represents a means for attaining full comprehension of the mechanical phenomena that are involved, something that neither three-dimensional elasticity nor finite elements and empirical formulas can attain. The transition from three to two-dimensional behavior is obtained by relating the normal stress in the direction transverse to the plate to the distortion in the interlayer. The two-dimensional behavior is governed using kinematic and force assumptions that do not impose appreciable constraints on the stress-strain state and structural behavior. Starting from these assumptions, the paper develops the relationships between displacements and interface stresses, for both continuous and discontinuous connection. The latter relationships, which are used in this model, and the former relationships, which were used in a previously presented model, are discussed and compared to each other. The subsequent sections of the paper describe the model and present some real case applications of discontinuously-connected layered plate. © 2012 Elsevier Ltd. All rights reserved. Source

This paper reports field test results to determine the dynamic behavior of a large all-GFRP space-reticular structure. The first experimental results are illustrated in the frame of a wider research aimed to study the dynamic and static performance of an all-GFRP structure built in L'Aquila (Italy), i.e. a temporary shelter to an ancient church collapsed after the earthquake of 6th of April 2009. Free vibrations were given to the structure with an instrumented hammer and recorded by a laser vibrometer. This kind of test gives the possibility to deduce some strategic information upon structural performance in the field of dynamic identification without invasive tests. In the detail the experimental data of the fundamental frequency and period and damping coefficient are here presented, together with displacements deduced. A comparison to a finite element analysis and closed form solutions suitable to structural vibration analysis allows first final considerations in the field of all-GFRP structure to be done. © 2011 Elsevier Ltd. Source

Foraboschi P.,IUAV University of Venice
Engineering Failure Analysis

The notorious October-31-2002 earthquake threatened the collapse of the church of San Giuliano di Puglia (Campobasso, Italy). This paper describes the main points of the repair and seismic retrofitting of the town church, San Giuliano Martire. The seismic retrofitting had to meet the new Italian seismic code that was issued immediately after this earthquake (seismic upgrading). The structural rehabilitation was limited because of the requirements to stay true to the original aspect (conservation of the bare-surface stone masonry, without plaster). To this end, the design considered recent scientific advancements and developed innovative methods, rather than just referring to technical practice. The rehabilitation work, in particular the technical innovation, has been tested by two earthquakes, both of them with an epicenter within close proximity to the building. The first one struck in 2007, with a magnitude of 3.1; the second one in 2011, with a magnitude of 3.7 and a Peak Ground Acceleration of 0.19{dot operator}. g. Whilst the sacral furniture resting on the ground suffered from significant damage, none of the earthquakes caused any structural damage to the building. In particular, no cracks opened in the masonry structures. The PGA and seismic forces of the 2011-earthquake were 1.7 and 2.5 times greater than the values prescribed by the present Italian code for the damage limitation and no-collapse requirements, respectively. This proves the effectiveness of applying post-tensioned bonded tendons to masonry structures, in order to significantly increase both the stiffness and the lateral load-carrying capacity of a masonry building. © 2013 Elsevier Ltd. Source

A programme of structural assessment and control is currently in progress at Palazzo Ducale in Venice, to evaluate the state of preservation of the two external Medieval façades. A long-term monitoring system of mono-directional accelerometers was set up to investigate the dynamic out-of-plane behaviour of the south façade along a vertical section. A type of action that could be taken as ordinary, involving frequencies in the range of 60-80. Hz, was identified during the first months of activity; the response to this kind of dynamic stress allowed a reliable evaluation of the dissipation properties of the structure. As well, the response to an extraordinary-type event, i.e. an earthquake, could be measured during the monitoring period. The first numeric elaborations based on experimental data are presented, i.e. a first calibration of the model of the south façade, aimed to establish the boundary conditions of the model (i.e. translational stiffness of connections to roof and floor structures), by means of spectral analysis with input experimental response spectrum. The good performance of this preliminary numerical model could finally be assessed. © 2012 Elsevier Ltd. Source

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