1,720,959 research outputs found
Seismic vulnerability assessment of an Italian historical masonry dry dock
No full textThe paper presents the seismic vulnerability analysis of the military dry dock built in 1861 inside the Messina's harbor. The study appears very important not only for the relevance of the dry dock itself, but also for its social, military and symbolic role. As a first step, the historical documentation about the dry dock delivered by the Military Technical Office, in charge of its maintenance, was thoroughly examined. This activity was fundamental to understand the construction methods, the rehabilitation works executed after the severe earthquake of 1908 and, finally, the works carried out to increase the size of the dry dock in 1950. After this first step, numerical seismic analyses were done with some implemented finite element models (FEM) of the structure. In each FEM, the vertical loads were applied according to the “construction stages” analysis technique, in order to achieve an appropriate representation of the soil stresses around the structure. The analysis results were evaluated according to the Italian design code (NTC 2008) in order to determine the seismic vulnerability of the dry dock
2D equivalent linear analysis for the seismic vulnerability evaluation of multi-propped retaining structures
Full text linkThe evaluation of the seismic behaviour of underground structures represents one of the most actual seismic geotechnical and structural engineering research topics about the study of the complex phenomena of soil-structural interaction. In the last decades, different types of simplified and numerical approaches have been developed for the correct analysis of the seismic vulnerability of these important infrastructures and a series of laboratory tests for the seismic behaviour characterization of the soils (resonant column test, etc.) and of the coupled soil-structure system (centrifuge test, etc.) have been conducted, especially after the recent strong earthquakes where the underground structures have been subjected to significant damages. In the same way, in the last few years, the International Codes are beginning to pay attention to the concepts of the seismic design of these structures. Despite the significant development of knowledge, described above, still remain open several uncertainties of the correct reproduction of the underground structures behaviour under seismic load. In this paper, the evaluation of the seismic behaviour of a multi-propped retaining structure was conducted, considering the soil-structure interaction effects. The results of the 2D equivalent linear analysis are analysed in terms of bending moment acting on the concrete retaining walls.L‘évaluation du comportement sismique des structures souterraines représentent un des sujets de
recherche les plus courants sismique, géotechnique et de construction, qui concerne l‘étude du phénomène
complexe de l‘interaction sol-structure. Pendant les dernières décennies, différents types d‘approches simples et
numeriques ont été développés pour une analyse exacte de la vulnérabilité sismique de ces infrastructures
importantes et encore une série de tests de laboratoire pour la caractérisation du comportement sismique du sols
(test de colonne résonnante etc.) et du système couplé du sol-structure (test de centrifugation etc.) ont été menées,
après le fort tremblement de terre où les structures souterraines ont subi des dommages importants. De la même
manière, pendant les dèrnieres années, les Codes Internationales ont commencé a prêter plus d‘attention aux
concepts de désign sismique de ces structures. Malgré la considèrable connaissance, décrit ci-dessus, il y a quand
même de l‘incertitude sur la correcte reproduction du comportement des structures sous charge sismique. Dans
cet article, il a été mené l‘evaluation du comportement sismique des structures de soutenement multi-etayé,
considérant que les effets de l‘interaction sol-structure. Les resultats de l‘analyse linéaire 2D equivalente sont
analysées en termes de moment de flexion agissant sur les murs de soutènement en béton
The new foundation system of the Basilica di Collemaggio's transept
No full textIn the seismic retrofitting of historical churches, the realisation of new foundations of collapsed elements represents an important aspect for the interaction with both the underground pre-existing structures and the new structural elements to be rebuilt. For the specific case study of the Basilica di Collemaggio, after an accurate geometrical survey and onsite geotechnical tests, a specific mixed structure foundation system is proposed in order to fulfil the seismicsafety requirements and the Cultural Heritage Office's conservation prescriptions. Nonlinear analyses are performed considering the interaction between the soil and the foundation system, together with the new couple of main pillars and the triumphal arch. The analyses are aimed to verify the capabilities of the new foundation system to bear the transversal seismic actions. The analyses are also completed by some experimental tests on micropiles, which represent the main underground-to-elevation connection elements
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
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
The advantages of fly ash use in concrete structures
Full text linkIn this paper the use of fly ash for particular High Strength Concrete (HSC) realizations is investigated. The use of fly ash as a partial replacement of Portland cement in HSC seems a valid solution in particular for a sustainable construction design, considering the interesting HSC performances (in terms of strength and durability) and the economic aspects (in terms of waste material's reuse from industrial process). Fly ashes have been employed in the past especially for underground structures. Nowadays, their use is under evaluation also for elevation structures. In this paper, the most important technical regulations about the use of fly ash for the concrete mix design are discussed. The increase of the mechanical resistance, the better protection against chemical agents attacks and freezing - thawing cycles using fly ashes are also show. Moreover, in comparison to the fresh concrete, the benefits related to the minor water/cement (w/c) ratio are presented, in the same workability conditions. Additional considerations are carried out about the hydration process: the mixture produces less heat for the lowering of the C3A and C3S percentages using fly ash. Finally, a greater concrete impermeability obtained using fly ash, due to the presence of a lower hydrolysis content, which leads to an increment of the cement paste porosity, has been evidenced. All of mentioned benefits shows the fly ash use in the High Strength Concrete (HSC) is a valid solution against many problems interested negatively the concrete mix - design and the mix - production
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
- …
