A modal analysis in linear elastic field for periodic masonry structures is proposed, based on co... more A modal analysis in linear elastic field for periodic masonry structures is proposed, based on continuous and discrete models. The continuum model is based on analytical homogenisation procedures, within the standard Cauchy and micropolar continuum theories, and the discrete model (DEM) describes masonry as a rigid skeleton. Both models are based on the assumptions of rigid blocks and mortar joints modelled as elastic interfaces.
Modal analysis, performed with continuous and discrete models, has been carried on both at Representative Elementary Volume (REV) level and at masonry panel level, such as to evaluate masonry sensitivity to local microstructure and to characteristic length of REV compared with the masonry panel size.
Hence, a parametric analysis is carried on to investigate the effect of (i) masonry texture (running versus header bond and other brick width-to-height ratios); (ii) size of heterogeneity; (iii) mortar elastic parameters; (iv) panel dimensions. Modal analysis is then carried on and compared also with a heterogeneous Finite Element Model (FEM) and a model already existent in literature (Brasile and Casciaro, 2009).
The proposed modal analysis for masonry is a first step to investigate the dynamic behaviour of masonry panels. Comparisons between several models has been performed to verify the reliability of the proposed procedures and to use these different approaches for a future development in non-linear field. In addition, a modal analysis is performed to examine a full-scale masonry shear wall with constraints such as to simulate a single shear wall in a two-story masonry building, with the aim to provide a case of technical interest.
As far as steel-concrete composite beams are concerned, the use of high performance concrete (HPC... more As far as steel-concrete composite beams are concerned, the use of high performance concrete (HPC) gives rise to an increased stiffness in the shear connectors and a reduction in ultimate slipping. A numerical simulation referring to simply supported beams demonstrates that, at least in the case of full interaction, the brittle behaviour of the connection does not significantly affect the load-bearing capacity of the structure because flexural failure of the midspan section due to rupture of the materials occurs before any shear failure of the connection due to its capacity for deformation being exceeded.
Lo studio del comportamento strutturale delle opere in calcestruzzo armato appartenenti al patrim... more Lo studio del comportamento strutturale delle opere in calcestruzzo armato appartenenti al patrimonio culturale del XX secolo rappresenta oggi un tema di grande interesse, che coinvolge sia aspetti pi\uf9 specificamente legati alla vulnerabilit\ue0 del costruito storico, sia le problematiche connesse alla realizzazione di un progetto di consolidamento in grado di coniugare i requisiti di sicurezza con i criteri di minimo intervento. In questo lavoro vengono analizzati i metodi di calcolo utilizzati per la realizzazione di tali opere, con particolare riferimento ad elementi inflessi realizzati secondo il brevetto Hennebique, allo scopo di costruire abachi direttamente utilizzabili dai progettisti a supporto delle loro analisi e per la progettazione delle campagne di indagini. Viene inoltre presentato un primo studio di dettaglio, che utilizza metodi avanzati, del comportamento di tali opere in campo non lineare, in grado di tenere conto di eventuali fenomeni di degrado/invecchiamento che possono influenzare significativamente la risposta strutturale
Local connection shear failure in the absence of adequate connection ductility can reduce steel a... more Local connection shear failure in the absence of adequate connection ductility can reduce steel and concrete composite element bending resistance. For these elements, Eurocode 4 contains design rules and criteria for checking that implicitly prevent early connection rupture, by limiting the value of the parameters influencing maximum slip capacity. Such indirect ductility checks can, however, only be applied within the constraints of their formulation hypotheses, such as material strength as specified in the document for instance. The use of high strength concrete substantially changes the ratio between maximum slip requirement and connection deformation capacity and demands direct connection ductility checking. This paper identifies the magnitudes affecting maximum slip requirement and suggests a simplified assessment method. The method, having general application, enables assessing connection efficiency to bending collapse of the composite beams and is particularly useful at the initial structure design stage as no demanding sophisticated analysis is required \ua9 2004 Elsevier Ltd. All rights reserved Keywords: Composite beams; Stud shear failure; Slip capacity; Maximum slip requiremen
Advances in Materials and Processing Technologies, 2016
Abstract The addition of new additives and materials to traditional lime mortars may engineer the... more Abstract The addition of new additives and materials to traditional lime mortars may engineer their self-healing capacity, i.e. make them able to repair an occurred mechanical damage. The phenomenon of self-healing may take place both at microscopic and macroscopic level and, in case, can be initiated by a dispersed phase that becomes available as a result of a mechanical damage. The idea underlying this work is hence twofold: first, a mortar is created with a part of the lime protected by an impermeable coating surface, able to make it inert during the phases of setting and hardening; the mechanical characteristic of this material are thus compared to those of a standard mortar. In a second stage, when the material is subjected to an external stress, the protective layer of the treated lime granules, should undergo a rupture which will trigger another step of setting and hardening in the material made dormant by the same treatment. The sealing of the cracks induced by the aforementioned applied stress will hence be made possible by the delayed reaction of hydration. The purpose of the work is to establish whether this kind of material can be employed in structural application with reference to its durability.
International Journal for Multiscale Computational Engineering, 2015
This paper investigates the sensitivity of the mechanical masonry characteristics to modeling pro... more This paper investigates the sensitivity of the mechanical masonry characteristics to modeling procedures, in several conditions of texture and material elastic properties. In a linear elastic field, both rigorous homogenization procedures and micro-modeling finite element techniques, in the framework of compatible identification procedures, are applied and compared to each other. The main aim of such an approach is to verify the reliability of the proposed procedures, identifying their applicability limits to the great variety of real masonry constructions. Finally, the actual vertical and horizontal joint thicknesses are taken into account in the formulation, and the effect of different degradation levels of vertical joints is investigated by means of sensitivity analyses in order to reproduce the typical conditions of ancient masonry
Pedestrian bridges are usually characterised by moderate dead loads and high deformability; such ... more Pedestrian bridges are usually characterised by moderate dead loads and high deformability; such conditions make them particularly sensitive to dynamic loads, which can induce significant vibrations. The footbridge over River Adige in Legnago (Northern Italy) is a triangulated space-lattice truss made using steel tubes; after its construction, the structure proved to be particularly sensitive to horizontal actions, that can produce an oscillation involving lateral translation and the deck torsion on its longitudinal axis. The effectiveness of the stiffening work - carried out in order to reduce such movements — has been assessed through analyses that were able to reveal the structure's response to dynamic loads, such as those induced by pedestrian traffic. In particular, the study was broken down into two successive analyses, following the current procedures for vibration control in similar structures. A modal analysis for the evaluation of natural frequencies and mode shapes (w...
Vengono presentati i risultati di una sperimentazione condotta su connettori metallici, costituit... more Vengono presentati i risultati di una sperimentazione condotta su connettori metallici, costituiti da una vite ed una piastrina, inserite l\u2019una nell\u2019altra, da utilizzare negli interventi di rinforzo di strutture esistenti per connettere nuove parti strutturali in calcestruzzo a quelle esistenti. I connettori sono stati sottoposti ad azione di taglio mediante prove di push-out, che hanno permesso di ricavare le loro caratteristiche resistenti e deformative (legame carico-scorrimento). La sperimentazione ha riguardato due resistenze del calcestruzzo; inoltre, al fine di evidenziare il ruolo svolto dalla piastrina, quale elemento caratterizzante il connettore oggetto di studio, alcune prove sono state condotte su campioni confezionati con la sola vite. La modalit\ue0 di crisi viene commentata e messa in relazione con quella descritta in letteratura per connessioni analoghe
A modal analysis in linear elastic field for periodic masonry structures is proposed, based on co... more A modal analysis in linear elastic field for periodic masonry structures is proposed, based on continuous and discrete models. The continuum model is based on analytical homogenisation procedures, within the standard Cauchy and micropolar continuum theories, and the discrete model (DEM) describes masonry as a rigid skeleton. Both models are based on the assumptions of rigid blocks and mortar joints modelled as elastic interfaces.
Modal analysis, performed with continuous and discrete models, has been carried on both at Representative Elementary Volume (REV) level and at masonry panel level, such as to evaluate masonry sensitivity to local microstructure and to characteristic length of REV compared with the masonry panel size.
Hence, a parametric analysis is carried on to investigate the effect of (i) masonry texture (running versus header bond and other brick width-to-height ratios); (ii) size of heterogeneity; (iii) mortar elastic parameters; (iv) panel dimensions. Modal analysis is then carried on and compared also with a heterogeneous Finite Element Model (FEM) and a model already existent in literature (Brasile and Casciaro, 2009).
The proposed modal analysis for masonry is a first step to investigate the dynamic behaviour of masonry panels. Comparisons between several models has been performed to verify the reliability of the proposed procedures and to use these different approaches for a future development in non-linear field. In addition, a modal analysis is performed to examine a full-scale masonry shear wall with constraints such as to simulate a single shear wall in a two-story masonry building, with the aim to provide a case of technical interest.
As far as steel-concrete composite beams are concerned, the use of high performance concrete (HPC... more As far as steel-concrete composite beams are concerned, the use of high performance concrete (HPC) gives rise to an increased stiffness in the shear connectors and a reduction in ultimate slipping. A numerical simulation referring to simply supported beams demonstrates that, at least in the case of full interaction, the brittle behaviour of the connection does not significantly affect the load-bearing capacity of the structure because flexural failure of the midspan section due to rupture of the materials occurs before any shear failure of the connection due to its capacity for deformation being exceeded.
Lo studio del comportamento strutturale delle opere in calcestruzzo armato appartenenti al patrim... more Lo studio del comportamento strutturale delle opere in calcestruzzo armato appartenenti al patrimonio culturale del XX secolo rappresenta oggi un tema di grande interesse, che coinvolge sia aspetti pi\uf9 specificamente legati alla vulnerabilit\ue0 del costruito storico, sia le problematiche connesse alla realizzazione di un progetto di consolidamento in grado di coniugare i requisiti di sicurezza con i criteri di minimo intervento. In questo lavoro vengono analizzati i metodi di calcolo utilizzati per la realizzazione di tali opere, con particolare riferimento ad elementi inflessi realizzati secondo il brevetto Hennebique, allo scopo di costruire abachi direttamente utilizzabili dai progettisti a supporto delle loro analisi e per la progettazione delle campagne di indagini. Viene inoltre presentato un primo studio di dettaglio, che utilizza metodi avanzati, del comportamento di tali opere in campo non lineare, in grado di tenere conto di eventuali fenomeni di degrado/invecchiamento che possono influenzare significativamente la risposta strutturale
Local connection shear failure in the absence of adequate connection ductility can reduce steel a... more Local connection shear failure in the absence of adequate connection ductility can reduce steel and concrete composite element bending resistance. For these elements, Eurocode 4 contains design rules and criteria for checking that implicitly prevent early connection rupture, by limiting the value of the parameters influencing maximum slip capacity. Such indirect ductility checks can, however, only be applied within the constraints of their formulation hypotheses, such as material strength as specified in the document for instance. The use of high strength concrete substantially changes the ratio between maximum slip requirement and connection deformation capacity and demands direct connection ductility checking. This paper identifies the magnitudes affecting maximum slip requirement and suggests a simplified assessment method. The method, having general application, enables assessing connection efficiency to bending collapse of the composite beams and is particularly useful at the initial structure design stage as no demanding sophisticated analysis is required \ua9 2004 Elsevier Ltd. All rights reserved Keywords: Composite beams; Stud shear failure; Slip capacity; Maximum slip requiremen
Advances in Materials and Processing Technologies, 2016
Abstract The addition of new additives and materials to traditional lime mortars may engineer the... more Abstract The addition of new additives and materials to traditional lime mortars may engineer their self-healing capacity, i.e. make them able to repair an occurred mechanical damage. The phenomenon of self-healing may take place both at microscopic and macroscopic level and, in case, can be initiated by a dispersed phase that becomes available as a result of a mechanical damage. The idea underlying this work is hence twofold: first, a mortar is created with a part of the lime protected by an impermeable coating surface, able to make it inert during the phases of setting and hardening; the mechanical characteristic of this material are thus compared to those of a standard mortar. In a second stage, when the material is subjected to an external stress, the protective layer of the treated lime granules, should undergo a rupture which will trigger another step of setting and hardening in the material made dormant by the same treatment. The sealing of the cracks induced by the aforementioned applied stress will hence be made possible by the delayed reaction of hydration. The purpose of the work is to establish whether this kind of material can be employed in structural application with reference to its durability.
International Journal for Multiscale Computational Engineering, 2015
This paper investigates the sensitivity of the mechanical masonry characteristics to modeling pro... more This paper investigates the sensitivity of the mechanical masonry characteristics to modeling procedures, in several conditions of texture and material elastic properties. In a linear elastic field, both rigorous homogenization procedures and micro-modeling finite element techniques, in the framework of compatible identification procedures, are applied and compared to each other. The main aim of such an approach is to verify the reliability of the proposed procedures, identifying their applicability limits to the great variety of real masonry constructions. Finally, the actual vertical and horizontal joint thicknesses are taken into account in the formulation, and the effect of different degradation levels of vertical joints is investigated by means of sensitivity analyses in order to reproduce the typical conditions of ancient masonry
Pedestrian bridges are usually characterised by moderate dead loads and high deformability; such ... more Pedestrian bridges are usually characterised by moderate dead loads and high deformability; such conditions make them particularly sensitive to dynamic loads, which can induce significant vibrations. The footbridge over River Adige in Legnago (Northern Italy) is a triangulated space-lattice truss made using steel tubes; after its construction, the structure proved to be particularly sensitive to horizontal actions, that can produce an oscillation involving lateral translation and the deck torsion on its longitudinal axis. The effectiveness of the stiffening work - carried out in order to reduce such movements — has been assessed through analyses that were able to reveal the structure's response to dynamic loads, such as those induced by pedestrian traffic. In particular, the study was broken down into two successive analyses, following the current procedures for vibration control in similar structures. A modal analysis for the evaluation of natural frequencies and mode shapes (w...
Vengono presentati i risultati di una sperimentazione condotta su connettori metallici, costituit... more Vengono presentati i risultati di una sperimentazione condotta su connettori metallici, costituiti da una vite ed una piastrina, inserite l\u2019una nell\u2019altra, da utilizzare negli interventi di rinforzo di strutture esistenti per connettere nuove parti strutturali in calcestruzzo a quelle esistenti. I connettori sono stati sottoposti ad azione di taglio mediante prove di push-out, che hanno permesso di ricavare le loro caratteristiche resistenti e deformative (legame carico-scorrimento). La sperimentazione ha riguardato due resistenze del calcestruzzo; inoltre, al fine di evidenziare il ruolo svolto dalla piastrina, quale elemento caratterizzante il connettore oggetto di studio, alcune prove sono state condotte su campioni confezionati con la sola vite. La modalit\ue0 di crisi viene commentata e messa in relazione con quella descritta in letteratura per connessioni analoghe
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