1,720,961 research outputs found
CONSOLIDATION AND RESTORATION OF HISTORICAL HERITAGE: THE FLAVIAN AMPHITHEATER IN ROME
No full textThe recovery and retrofitting techniques adopted for historical structures and archaeological sites face an apparent dichotomy between conservation of constructions and the safety of users. Literatures show several examples where the current day structural safety of historical constructions, gets defined by the nature of past interventions, the compatibility of materials and elements used in retrofitting. The adopted interventions were, in their time, considered innovative, but over the years their compatibility and reversibility leave the historic constructions structurally vulnerable. For these reasons, a careful understanding of the structural systems is fundamental for the implementation of appropriate retrofitting solutions. Especially for monuments and Archaeological sites the objective to be achieved has to be clear, avoiding destructive investigation tests. In this work the instabilities caused by a consolidation intervention on some travertine columns in a sector of the Flavian Amphitheatre, better known as "Colosseum “in Rome, are critically analysed. The current consolidation operations are compared to the previous one. The restoration activity involves in-depth diagnosis process: the historical analysis of the failures and restorations of that area of the Colosseum, a survey of the crack pattern and an indirect investigation on the travertine of the columns. Subsequently the various data coming from the knowledge phase are elaborated, in order to have a correct interpretation of the causes triggering the failure and guide the choice of the most correct retrofitting techniques
Experimental Assessment of the Cyclic Behaviour of RC-DP Beam to Column Joints
No full textCorrosion represents one of the most important problems affecting the global behaviour of reinforced concrete (RC) buildings; in presence of aggressive environmental conditions reinforcing steel bars, as well as concrete, suffer from relevant modifications of the mechanical performance. Steel rebars show a high decrease of the deformation capacity, with reduction of the elongation to maximum load up to the 50% in case of TempCore® grades. This can cause unexpected brittle failures related to the premature achievement of ultimate rotation or, even worst, shear capacity of structural elements. To mitigate these problems, actual European standards for constructions foresee the adoption of specific precautions such as the increase of concrete strength class, of the concrete cover, of higher diameter; these tools allow to reduce the effects of corrosion without deleting the origin of the matter. During the last years, otherwise, another typology of reinforcing steel–characterized by a typical Dual-Phase (DP) microstructure–was developed with the aim of directly preventing corrosion initiation. Due to their microstructure, in which martensite is embedded in the ferrite matrix, Dual-Phase steels are less exposed to corrosion; on the other hand, being characterized by a not-defined yielding stress-strain plateau, specific rules need to be elaborated for their employment in civil applications. In the present paper, the experimental test campaign performed on reinforced concrete internal and external joints with Dual-Phase steel rebars is deeply described together with results’ critical discussion. The paper is preparatory for the elaboration of technical models to be used in the design of RC-DP structures
Seismic vulnerability assessment of historical urban centres: The case study of campi alto di norcia, Italy
Full text linkSeismic damage assessment is a valuable opportunity to evaluate the accuracy of vulnerability and risk methodologies applied to historic masonry buildings, giving the possibility of enhancing and optimizing mitigation and retrofit strategies. Vulnerability index methodologies are flexible and powerful tools for the seismic assessment at urban scale, able to provide a first screening of the critical issues present in masonry structural aggregates. The different structural features of the buildings, directly and indirectly influencing their structural behaviour, are measured through different weights and scores finally achieving a vulnerability indicator. In the present paper, four different vulnerability index methodologies are applied to the medieval city of Campi Alto di Norcia in Valnerina, Umbria, recently stroke by the 2016 Central Italy earthquakes. The accuracy of the adopted Iv methods is assessed based on the real damages' analysis performed in the surrounding area, comparing results achieved from the application of considered methodologies to direct in-situ observations. Data collected during the 2016 post-earthquake damage surveys and usability assessment, together with the external visual inspections carried out and with the information coming from retrofitting design interventions performed between 1979 and 1997, are used
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
An improved seismic vulnerability assessment approach for historical urban centres: The case study of campi alto di norcia, Italy
Full text linkSeismic damage assessment is an extraordinary opportunity to evaluate the reliability of vulnerability and risk methodologies applied to historic masonry buildings, giving the possibility of enhancing and optimising mitigation and retrofit strategies. Vulnerability index methodologies are flexible and powerful tools for assessing seismic vulnerability on the urban scale, providing a first screening of the critical issues present in masonry buildings and a possible priority list for the following retrofit operations. Such approaches account for the buildings’ different structural characteristics, directly or indirectly influencing their seismic behaviour and measured through different weights and classes finally providing a vulnerability index. In this paper, we show the application of three well-known methodologies to Campi Alto di Norcia’s medieval city in Valnerina (Italy) stroke by the earthquakes of 24 August and 30 October 2016. The methodologies’ reliability is assessed, based on the observation of real seismic consequences and damages on the masonry buildings, and an optimised methodology is then proposed for the considered case study
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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