1,720,965 research outputs found
Upgraded experimental database of uniformly FRP confined concrete columns for assessment of existing recommendations
No full textCurrent studies concerning statistical elaboration and review of existing experimental results in databases, usually include only the characteristic maximum bearing stress and corresponding strain values as well as the failure values. In cases of uniform confinement
failure values may be defined at 20% or 15% drop of maximum load or when the FRP jacket is fractured. Several recommendations include additional failure criteria related to lateral strain level or axial strain level in order to ensure the integrity of the columns or avoidance of
shear failures among else. An experimental database based on the whole stress-strain response curves is presented, providing significant data necessary for the extensive assessment of the existing design models. The experimental database contains information on: a) the failure
stress and strain values, b) on the stress and strain values at the level of 0.4% lateral strain as well as c) on the stress at the level of 1% axial strain. FRP confinement strength models recommended by existing guidelines are compared against experimental values
Peak strength and ultimate strain prediction for FRP confined square and circular concrete sections
No full textIt is widely accepted that axially loaded FRP confined concrete presents significant strength and ductility increase with reference to the unconfined case. Adequate FRP confinement provides bilinear – like and hardening stress–strain behavior to concrete up to failure. Therefore, to model the mechanical behavior of adequately confined concrete two quantities are necessary: peak strength and ultimate strain. Many studies have been published regarding confinement of circular section elements; fewer studies analyze the case of square and rectangular section. Numerous predictive expressions of peak strength and ultimate strain, suitable for circular section elements, are available. Only in recent years, complete equations have been proposed to cover both circular and square sections. The aim of this work is the assessment of the performances of significant predictive expressions published in literature. Four groups of predictive expressions have been considered; they differ by the type of the predictive quantity (peak strength or ultimate strain) and by their applicability (only circular sections or both circular and square sections). For this reason a wide database has been assembled; it collects results of more than 655 compressive tests, performed on square and circular specimens confined with FRP. This comparison has been diversified as a function of cross section shape and FRP type (CFRP, GFRP, AFRP)
Behaviour and capacity of CFRP-confined concrete cylinders subjected to monotonic and cyclic axial compressive load
No full textModelling of Deformable Polymer to be Used for Joints Between Infill Masonry Walls and R.C. Frames
No full textIn the paper an idea to use a deformable polymer material for the joint between R.C. frames and masonry infills is presented. As
an early step of testing the idea, experimental tests of the polymer in monotonic uniaxial tension at different load rates are
performed and analyzed. The load rates range from very fast (8.3 mm/s) to very slow (0.00083 mm/s). The material exhibits a
very strong strain rate effect and viscous behavior. In the second part of the paper a numerical model is developed and
implemented into a finite element to simulate the results of the tests. The model is based on a new family of strain measures,
called the Darjani-Naghdabadi strain measures and a classical viscosity formulation. Almost perfect model predictions up to
collapse at 50-150 % elongation are obtained by using calibration based on minimization of error
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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