1,720,956 research outputs found
An equivalent beam approach for assessing tunnelling-induced distortions of frames with infills
No full textThis paper presents an approach to evaluate the response of low- and medium-rise frames with continuous foundations, either with or without infills, to tunnelling employing an equivalent beam with a behaviour dominated by shear deformations. Simplified soil-structure interaction models, consisting of a beam resting on an elastic continuum half-space, are compared against advanced three-dimensional analyses in which the tunnel, the soil, and the building are explicitly modelled. In the simplified approach, the frame is schematised as a Timoshenko beam and reliable procedures to estimate both bending and shear stiffness are discussed. In the refined modelling strategy, an advanced elastoplastic constitute law is employed, capable of reproducing fairly well the soil response to the excavation for increasing values of volume loss, while the full geometry of the structure is considered. First, the results of the proposed numerical approaches are compared in terms of tunnelling-induced foundation displacements, bay deformations and maximum tensile strains in the infills. Then, for the infill panels, the reliability of estimating the maximum tensile strain from the angular distortion of the frame bays is assessed. Finally, a meta-model is proposed to predict the maximum angular distortion based on greenfield settlements, eccentricity, and relative soil-structure stiffness
Numerical modelling of framed structures with masonry infills affected by tunnelling-induced deformation and damage
No full textThe paper describes a numerical approach aimed at investigating the response of framed structures with masonry infills to tunnel excavation in sand. The numerical model, analysed with the Finite Element method, includes the soil, the tunnel and the framed structure with infills. It proved its capability in reproducing the soil response at different values of the volume loss and the principal soil-structure interaction mechanisms, including sliding and development of a gap at the soil-foundation interface. The results are summarised in terms of angular distortion values for each bay as well as local tensile strains in the masonry infills. Finally, the efficiency of angular distortion models in predicting the maximum tensile strain of the infills is also evaluated
Numerical modelling of framed structures with masonry infills affected by tunnelling-induced deformation and damage
No full textThe paper describes a numerical approach aimed at investigating the response of framed structures with masonry infills to tunnel excavation in sand. The numerical model, analysed with the Finite Element method, includes the soil, the tunnel and the framed structure with infills. It proved its capability in reproducing the soil response at different values of the volume loss and the principal soil-structure interaction mechanisms, including sliding and development of a gap at the soil-foundation interface. The results are summarised in terms of angular distortion values for each bay as well as local tensile strains in the masonry infills. Finally, the efficiency of angular distortion models in predicting the maximum tensile strain of the infills is also evaluated
Tunnelling-induced displacements and damage on framed structures. Comparison between numerical models
No full textThe paper focuses on the response of framed structures to tunnel excavation in sand. Standard 3D Finite Element analyses, in which the structural elements are explicitly detailed, as well as simplified equivalent beam models were adopted to simulate the influence of the frame and that of the masonry infills. Both approaches well captured the main soil-structure interaction mechanisms. The presence of stiff masonry infills was found to reduce the angular distortions of the frame bays and, as such, to reduce the tunnelling induced damage. For the first time, insights into the efficiency of two-stage models implementing equivalent Timoshenko beams for framed buildings are given
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
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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