1,720,961 research outputs found
A modern approach to strengthening and repair of existing reinforced concrete structures using High Performance Fibre Reinforced Concrete
No full texthis work presents a critical review of current trends in strengthening and repairing of existing reinforced concrete (RC) structures using modern materials. The attention is particularly
given to the application of High Performance Fibre Reinforced Concrete (HPFRC) jackets, being in the focus of scientific community in the past few years. Based on the literature review and stateof-the art in this field, a comparison has been done with other widely used techniques, such as external bonding of Fibre Reinforced Polymer (FRP) composites or RC overlaying. Moreover,
the technique effectiveness has been discussed analysing experimental results available in the literature, not only in terms of engineering features (e.g. load capacity or fire resistance), but
also considering particular aspects in case of application to the RC heritage structures, being an important part of Europe’s modern heritage
A multidisciplinary approach for the assessment of great historical structures: Ties of “Duomo di Milano”
No full textAn investigation methodology, based on a scientific approach for historical structures, has been applied to the case study of the Duomo di Milano. In particular, a continuous process of data acquisition, analysis of structural behaviour, diagnosis and safety evaluation is followed with the aim of assessing metallic ties present in the Cathedral. Different techniques and fields of expertise were used for data acquisition: historical investigation gave important information on the ties origin, their structural purpose and the construction process of the Cathedral; the wide experimental campaign included visual inspection, material characterization, and dynamic tests on the original ties and contributed to the understanding of the structural system. The main results and considerations from such a multidisciplinary investigation are presented in the paper, providing a reference from a real case-study. Relevant aspects for the study of the Cathedral’s structural behaviour are addressed, various approaches to be used are proposed, such as limit analysis or Finite Element Modelling (FEM) and their benefits are outlined. These models, once validated through the prediction of past and present states of the structure, will be used during diagnosis and safety evaluation to predict the future behaviour, or identify potential causes of eventual observed damage, as well as to evaluate the current state of the stress in ties measured with a more refined Non-destructive testing (NDT) approach
Dynamic assessment of the axial force in the tie-rods of the Milan Cathedral
Full text linkmetallic tie-rods are installed under all naves to support a portion of the lateral thrust exerted by vaults and arches. After the recent failure of one tie-rod, an extensive research program was carried out to characterize the metallic material and to evaluate the axial forces and the tensile stresses of the tie-rods through dynamic testing and system identification. After a description of the methodology of the dynamic assessment of tie-rods in the Milan Cathedral, the paper presents the main results of the investigation in terms of fundamental frequencies and axial forces in the tie-rod
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Fatigue behaviour of the historical wrought iron tie rods in the Duomo di Milano
Full text linkLAUREA MAGISTRALELo stato attuale e la “risposta” strutturale degli edifici storici sono parametri fondamentali da comprendere se si vuole capire le loro “risposte” future e le loro vite residue. La valutazione di questi particolari edifici può essere effetuata considerando diversi aspetti come: la ricerca di documenti storici quali progetto originario,evoluzione delle fasi costruttive e dei eventuali danni nel tempo, il monitoraggio, analisi numeriche ed etc. Il caso studiato in questa tesi riguarda il Duomo di Milano, più nello specifico la risposta a fatica delle sue catene a diverse temperature. Le catene sono soggette ad una forza di trazione dovuta dalla spinta laterale delle volte e degli archi sopra di esse. La loro stabilità è essenziale al fine di garantire una buona risposta strutturale, per questo motivo la loro verifica è molto importante. Le catene sono in ferro battuto, a causa delle scarse informazioni dell’analisi storica riguardanti le loro proprietà (fisiche,chimiche e meccaniche), si è provveduto ad eseguire alcuni test su pezzi di esse come: ispezione visiva, prova a trazione, analisi con particelle magnetiche e prova di durezza. Il modello numerico usato per definire l’influenza del cambiamento di temperatura stagionale e giornaliero si basa su dati provenienti da studi effetuati in passato oltre che a quelli delle prove qui condotte. Lo scopo di questa tesi è quello di fornire informazioni sulla stima della resistenza residua a fatica delle catene con la presenza di un difetto individuate in esse usando un modello numerico basato sulla meccanica lineare elastica delle fratture. Nel presente lavoro vi sono anche alcuni suggerimenti per future approfondimenti, in maniera tale da migliorare l’analisi.When dealing with historical buildings it is very important to understand their structural behavior and present state in order to be able to predict their future performance and residual life. The assessment of this kind of buildings consists of many aspects such as historical investigation of the original design, evolution of construction and damage in time, monitoring, numerical models etc. The Cathedral of Milan (further in the text indicated as Duomo di Milano) was chosen as a case study for the present thesis for which the fatigue behavior of its iron ties due to the temperature change was assessed. Tie-rods in Duomo di Milano are active in bearing the lateral thrust from the vault and the arch above. Their stability is relevant for the overall performance of the structure, which makes their assessment of great importance. Since the ties are made of wrought iron, for which little information on the material properties is available in the literature, series of experiments were conducted on specimens, taken from the original tie – visual inspection, tensile test, magnetic particle examination, and toughness test. The data from previous studies, monitoring and investigations of the structure were used in order to create a simplified numerical model for assessing the influence of the daily and seasonal temperature variations on the elements. The aim of the thesis is to provide instructions for estimation of the residual fatigue life of the ties once a defect in them has been detected, using the results from the numerical model along with the principles of Linear Elastic Fracture Mechanics (LEFM). Some remarks on further improvements of the models are given in the present work in order to improve the obtained results
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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