1,720,967 research outputs found
Influence of Compressive Stresses on the Concrete Cone Breakout Capacity of Cast‐in‐Place Headed Anchors
No full texthttp://www.northeastern.edu/emi2011/
Pullout Capacity of Headed Anchors in Prestressed Concrete
No full textA combined experimental and computational study shows that the pullout capacity of anchors embedded at small depths in prestressed concrete is associated with the strongest possible (linear elastic fracture mechanics) size effect. A design formula is proposed that reflects the effects of embedment depth and the nondimensional parameters that quantify the level of prestressing and the characteristic length of the matrix
BREAKOUT CAPACITY OF HEADED ANCHORS IN CONFINED CONCRETE: EXPERIMENTAL EVIDENCE
No full textWhile provisions are available in the current design codes that account for the presence of tensile fields causing concrete cracking, no provisions are available for anchors embedded in compressively prestressed concrete. Because of this lack of information, a series of experiments were performed to evaluate the tensile breakout capacity of headed anchors embedded in confined and unconfined concrete. To simulate the confinement, uniform biaxial compression (prestress) was applied to concrete specimens in the directions orthogonal to the anchors’ stems.
This paper discusses the influence of embedment depth and confinement on the behavior of headed anchors in terms of strength, ductility, and failure pattern. A comparison between actual code provisions for unconfined concrete and the experimental results reported herein is provided. Proposals for the extension of the actual provisions to take into account for the effects of confinement are provided and are contingent upon completion of further investigation
Effect of cyclic loading protocols on the experimental seismic performance evaluation of suspended piping restraint installations
No full textSuspended non-structural elements, such as water and sprinkler piping systems, are key to the functionality of important facilities, such as hospitals and schools. Recent earthquakes have demonstrated the vulnerability of these systems, particularly for those that were inadequately restrained. Seismic qualification requirements of non-structural elements contained in recent building codes and industry standards rely on experimental procedures, such as quasi-static cyclic testing of components and sub-assemblies. When conducting such quasi-static testing, the question arises as to what proper loading protocol to use. The first part of this paper reviews and compare existing cyclic loading protocols for testing various types of components and sub-assembles and developed according to scientific methods, including two specifically developed for testing non-structural elements. These two non-structural loading protocols are then used for conducting quasi-static cyclic testing of common components part of piping restraint installations. Characteristic response parameters resulting from test results with each cyclic loading protocol are extracted and compared. Observations and recommendations are provided on the effects of using different cyclic loading protocols for the performance evaluation and seismic qualification testing of suspended piping restraint installations
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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