Steel-concrete composite framed buildings are highly efficient structural systems due to their stiffness, strength and ductility. Such systems allow also adequate seismic performance nevertheless their application in seismic area is... more
Steel-concrete composite framed buildings are highly efficient structural systems due to their stiffness, strength and ductility. Such systems allow also adequate seismic performance nevertheless their application in seismic area is prevented by the lack of experimental information and design rules, especially about joints and plastic hinges. The present work is focused on the seismic design and assessment of a typical steel - concrete composite multi-story moment-resisting frame. Provisions implemented in European standards are discussed especially when uncertainties about their application come out; in fact a number of European provisions are not straightforward and/or reliable and further improvements are necessary. Recent seismic codes, for the design of a structure, require the use of capacity design criteria based on the hierarchy of strength and energy dissipation, developing plasticization that involve the nodal zone. As a result, to perform an adequate non-linear analysis, ...
ABSTRACT The behaviour of composite joints continues to be an issue of interest in the area of steel and composite structures. The progress achieved in the programming and computer technology made possible the application of advanced 3D... more
ABSTRACT The behaviour of composite joints continues to be an issue of interest in the area of steel and composite structures. The progress achieved in the programming and computer technology made possible the application of advanced 3D Finite Element Method for the analysis of composite steel concrete frame joints and simulate their real behaviour. The goal of this 3D modelling is to obtain " Load-deflection " curves as close as possible to the ones experimentally obtained, in a practical way and with reduced cost and time. The study presents in detail two illustrative examples created by using 3D FEM for a welded joint and a joint with extended end plate. For both joints, a nonlinear static analysis was applied using ABAQUS commercial code, ver. 6.11 and the obtained results were compared with experimental full-scale composite joints conducted by the authors. The numerical models were created by using 3D finite elements of solid type C3D4R, considering the contact between components and the bolts pre-tensioning. A Concrete damaged plasticity " CDP " model was used for concrete material and a steel damage option based on Gurson's porous metal plasticity theory was used for the steel structure. The analysis focused on the state of stress at each loading step, the failure mode in comparison with the one experimentally observed, and the comparison of the Load-Deflection predictions curves with the ones experimentally obtained.
La progettazione in zona sismica di una struttura intelaiata composta risulta molto più com-plessa di quella di una struttura in solo acciaio a causa della presenza della soletta, della sua in-terazione nella zona di plasticizzazione... more
La progettazione in zona sismica di una struttura intelaiata composta risulta molto più com-plessa di quella di una struttura in solo acciaio a causa della presenza della soletta, della sua in-terazione nella zona di plasticizzazione della trave e della complessità del nodo. Nel presente lavoro, suddiviso in due parti, si presentano le problematiche relative sia alla modellazione del nodo che del telaio composto qualora si effettui una analisi non lineare di pushover. In questa prima parte, si affronta il problema relativo alla progettazione e modellazione del giunto composto mediante il metodo per componenti, così come recepito dagli Eurocodici 3, 4 ed 8. In particolare, vengono dapprima analizzati e approfonditi i meccanismi resistenti sia per un nodo saldato che flangiato a completo ripristino di resistenza, focalizzando l’attenzione sul-la progettazione della soletta in calcestruzzo e sui meccanismi tirante-puntone in corrisponden-za della zona nodale. Successivamente viene affr...
2013/2014Nella presente tesi si sono analizzate le principali problematiche relative alla modellazione non lineare delle strutture composte intelaiate in zona sismica. Nella prima parte si sono esaminati in dettaglio i criteri attualmente... more
2013/2014Nella presente tesi si sono analizzate le principali problematiche relative alla modellazione non lineare delle strutture composte intelaiate in zona sismica. Nella prima parte si sono esaminati in dettaglio i criteri attualmente adottati nella progettazione classica delle strutture intelaiate composte acciaio-calcestruzzo, facendo principalmente riferimento alle indicazioni sismiche fornite dall’Eurocodice 8. Successivamente si è affrontato il tema della progettazione del giunto composto, a questo proposito si è definito un iter progettuale con una procedura semplificata passo-passo utilizzando un software sviluppato in Excel. Tale software è stato sviluppato con lo scopo principale di facilitare la progettazione dei giunti saldati e flangiati indicando i passi e le verifiche da eseguire fino all’ottenimento della risposta in termini di momento-rotazione. La procedura di progettazione è stata poi validata sulla base di un test sperimentale per entrambi i giunti. Nel terzo ...
Nella progettazione dei telai composti acciaio-calcestruzzo, seguendo le indicazioni normative basate su criteri di Capacity Design, riveste un ruolo molto importante la questione legata alla dissipazione energetica e alla gerarchia delle... more
Nella progettazione dei telai composti acciaio-calcestruzzo, seguendo le indicazioni normative basate su criteri di Capacity Design, riveste un ruolo molto importante la questione legata alla dissipazione energetica e alla gerarchia delle resistenze. Secondo tali indicazioni, una delle strategie più efficaci in ambito sismico è quella di sviluppare la plasticizzazione alle estremità delle travi, evitando la formazione della stessa nelle colonne (colonna forte/trave debole). Di conseguenza, diventa molto importante la corretta modellazione della zona plastica e garantire che il nodo trave-colonna sia sufficientemente rigido e resistente. Nel presente lavoro si analizzano le problematiche relative alla modellazione delle zone plastiche utilizzando un modello a plasticità concentrata basato sull’uso di cerniere rigido-plastiche o di elementi link non lineari. In entrambi i casi sono fornite indicazioni utili alla modellazione. Effettuando delle analisi di pushover mediante il codice di...
Steel-concrete composite framed buildings are highly efficient structural systems due to their stiffness, strength and ductility. Such systems allow also adequate seismic performance nevertheless their application in seismic area is... more
Steel-concrete composite framed buildings are highly efficient structural systems due to their stiffness, strength and ductility. Such systems allow also adequate seismic performance nevertheless their application in seismic area is prevented by the lack of experimental information and design rules, especially about joints and plastic hinges. The present work is focused on the seismic design and assessment of a typical steel - concrete composite multi-story moment-resisting frame. Provisions implemented in European standards are discussed especially when uncertainties about their application come out; in fact a number of European provisions are not straightforward and/or reliable and further improvements are necessary. Recent seismic codes, for the design of a structure, require the use of capacity design criteria based on the hierarchy of strength and energy dissipation, developing plasticization that involve the nodal zone. As a result, to perform an adequate non-linear analysis, ...
Strumenti/Scenari Collana diretta da Pietro Barcellona, Raffaele De Giorgi, Gianluigi Palombella Comitato scientifico B. Amoroso, T. Blanke, A. Caillé, JR Capella, S. Latouche, M. Maresca, G. Teubner L'89 è certamente uno spartiacque... more
Strumenti/Scenari Collana diretta da Pietro Barcellona, Raffaele De Giorgi, Gianluigi Palombella Comitato scientifico B. Amoroso, T. Blanke, A. Caillé, JR Capella, S. Latouche, M. Maresca, G. Teubner L'89 è certamente uno spartiacque epocale. All'euforia di una unificazione ...
Page 1. 595 Research Article Received: 14 August 2008 Accepted: 9 October 2008 Published online in Wiley Interscience: 21 November 2008 (www.interscience.wiley.com) DOI 10.1002/jrs.2162 Raman and FTIR imaging of lung tissue:... more
Page 1. 595 Research Article Received: 14 August 2008 Accepted: 9 October 2008 Published online in Wiley Interscience: 21 November 2008 (www.interscience.wiley.com) DOI 10.1002/jrs.2162 Raman and FTIR imaging of lung tissue: bronchopulmonary sequestration ...
Congenital cystic adenomatoid malformations (CCAMs) are benign masses of non-functional lung tissue developing from an overgrowth of the terminal bronchioles with subsequent suppressing of alveolar growth. For the first time CCAMs are... more
Congenital cystic adenomatoid malformations (CCAMs) are benign masses of non-functional lung tissue developing from an overgrowth of the terminal bronchioles with subsequent suppressing of alveolar growth. For the first time CCAMs are studied by Raman mapping and Fourier transform infrared (FTIR) imaging. Both vibrational spectroscopic methods are able to analyze the biochemical composition of tissues and their pathological changes at the molecular level. Cryosections were prepared on calcium fluoride substrates from CCAMs and from normal lung tissue of two infant patients who underwent surgery. Raman maps were collected at a step size of 100 microm in order to assess the whole tissue section and at a smaller step size of 10 microm in order to resolve details in selected areas. FTIR images were collected in the macroscopic and microscopic modes. Data sets were segmented by cluster analysis and the mean spectra of each cluster were compared. At low lateral resolution a lower red blood cell content and higher lipid content were found in CCAMs than in normal lung tissue. At higher lateral resolution, accumulations of lipids and glycogen were identified in CCAMs. The lipid aggregates contain a high concentration of phosphatidylcholine. It is discussed how the combined application of Raman mapping and FTIR imaging might improve the differential diagnosis of lung malformations and how both modalities might be applied to other bioanalytical and biomedical problems in the future.
The paper describes Raman and FTIR images of normal lung tissue of an infant patient which is a prerequisite to understand the biochemical changes that accompany pediatric lung pathologies and malformations. A Raman image of 3420 spectra... more
The paper describes Raman and FTIR images of normal lung tissue of an infant patient which is a prerequisite to understand the biochemical changes that accompany pediatric lung pathologies and malformations. A Raman image of 3420 spectra was recorded from a 5.7 mm × 6 mm ...
... gynecological screening for cervical dysplasia and malignancies. The initial work of Wong and coworkers on FTIR spectroscopy of cervical cancer started the field of FTIR diagnostics [162]. Since then most FTIR studies have ...
Colon tissue constitutes a valid model for the comparative analysis of soft tissue by Raman and Fourier transform infrared (FTIR) imaging because it contains four major tissue types such as muscle tissue, connective tissue, epithelium and... more
Colon tissue constitutes a valid model for the comparative analysis of soft tissue by Raman and Fourier transform infrared (FTIR) imaging because it contains four major tissue types such as muscle tissue, connective tissue, epithelium and nerve cells. Raman microscopic images were recorded in the mapping mode using 785 nm laser excitation and a step size of 10 microm from three regions within a thin section that encompassed mucus, mucosa, submucosa, and longitudinal and circular muscle layers. FTIR microscopic images that were composed of 4, 8 and 9 individual images of 4096 spectra each were recorded from the same regions using a FTIR spectrometer coupled to a microscope with a focal plane array detector. Furthermore, Raman microscopic images were recorded at a step size of 2.5 microm from three ganglia that belong to the myenteric plexus. The results are discussed with respect to lateral resolution, spectral resolution, acquisition time and sensitivity of both modalities.
