1,721,086 research outputs found
Strip Model Analysis for Steel Plate Shear Walls in Earthquake Resistant Structures
Full text linkUnstiffened Steel Plate Shear Walls (SPSWs) are very effective structural systems designed to resist lateral forces. SPSW systems consist of thin web plates infilled within frames of steel horizontal and vertical boundary elements. The thin unstiffened web plates are expected to buckle in shear and to develop diagonal tension field after buckling under the action of horizontal loads. For unstiffened steel plates, buckling in shear occurs in the elastic range at low stress levels. This behaviour provides strength, stiffness and ductility and allows to have an appropriate level of energy dissipation through tension yielding of the web plates. This paper assesses the inelastic structural response and behaviour of Steel Plate Shear Wall systems using both a modified strip model approach and a new simplified strip model for only beam connected SPSWs. Both models are developed with plasticity concentrated elements and the performed analyses include the nonlinear behaviour of strips, also considering the compressive forces effects over the strip model elements. This research indicates fundamental aspects of the seismic performance of Steel Plate Shear Wall systems, such as energy dissipation capacity, panel ductility demand, seismic inter-story drift and design load demands in Vertical Boundary Elements (VBE) and Horizontal Boundary Elements (HBE) of the frame. The results obtained from the use of these models are compared with selected experimental and numerical results to enrich the research conclusions.</jats:p
Ductility and Behaviour Factor of RC Frame - Perforated SPSW Dual Systems
Full text linkIn this paper the non-linear behaviour of dual seismic-resistant structures made of Reinforced Concrete Frames (RCF) and perforated Steel Plate Shear Walls (SPSWs) has been investigated. The starting point has been the numerical calibration by ABAQUS of an experimental test taken from literature on one-third scale three-storey RCF with infill SPSWs subjected to monotonically increasing horizontal loading. Based on results of the implemented FEM model, three types of perforated SPSWs with different percentages and position of holes have been numerically analysed through static non-linear analyses. On the basis of numerical results achieved, by comparing each other the values of shear strength, behaviour factor and ductility of the tested specimens, it has been observed a significant improvement of the ductile behaviour of the RCF equipped with perforated SPSWs with respect to the one obtained for the RCF provided with traditional solid SPSWs. In addition, the dual systems given by RCF and perforated SPSWs have provided a shear strength reduction of 26%, 46% and 51% in comparison to that of the original RCF - solid SPSW composite system, when holes percentage equal to 13%, 40% and 42% have been considered, respectively. Finally, it has been noticed that behaviour factors of perforated specimens have been increased with increasing adjoining distance among holes.</jats:p
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
Capacity Design Criteria of 3D Steel Lattice Beams for applications into cultural heritage constructions and archaeological sites
Full text linkThree-dimensional lattice beams are highly efficient technical solutions to cover large spans, especially when the single members do not have intermediate restraints able to prevent lateral-torsional buckling phenomena. Hence, lattice structures are widely applied in any field of civil and industrial engineering. In the present paper, in the framework of a research project funded by both the Campania Region and the European Community, a compound structure made of welded lattice beams and structural glass slabs is proposed as a structural system for valorisation and protection of monumental constructions and archaeological sites. Due to both the risk exposure of monumental heritage to be protected and the use of structural glass, the definition of an appropriate design criterion is mandatory in order to avoid development of brittle collapse mechanisms, mainly under static and dynamic vertical loads. The attention is herein paid to the design procedure, with a brief description of basic ideas behind the project itself and the main focus on the parametric capacity design of structural members. The proposed procedure, whose validity is quite general, has been subsequently verified by linear and non-linear numerical analyses calibrated on the basis of experimental investigations carried out on both the beam material and full-scale beam prototypes.</jats:p
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
Numerical Study on Moment Resisting Frames under Monotonic and Cyclic Loads
No full textMoment Resisting Frames (MRF) should ideally dissipate the seismic energy through the
development of plastic hinges in the beams and at the column bases with the purpose to pursue a
global failure mechanism. The current seismic design criteria, through hierarchy resistance and
ductility requirements, are conceived to achieve this objective. However there are still some
inaccuracies in the prediction of the structural performances, mainly under cyclic loadings, as much
important as the number of bays and stories augments.
The current paper would give a contribution for deepening key issues related to MRF seismic
behavior, presenting the numerical simulation of some literature experimental tests conducted on
simple portal MRF subjected to monotonic and cyclic loads both in presence and in absence of
vertical loads.
The refined Finite Element structural models of the study systems are developed through the
software ABAQUS (v6.13-1). The models set up provide very good replications of both monotonic
and hysteretic behaviors in terms of strength, stiffness, ductility and energy dissipation. They
represent powerful analysis instruments to perform parametric studies, aiming at detecting the main
factors affecting the seismic behavior of MRFs, thus leading towards appropriate design criteria
Numerical study on concentric braced X frames under monotonic and cyclic loads
No full textConcentric Braced Frames (CBF) are designed for dissipating the seismic energy mainly through plastic deformations of diagonals in tension, while beams and columns, designed on the basis of the hierarchy resistance criterion, should resist the design loads in elastic field without undergoing buckling and yielding phenomena. For such structural systems there are still some uncertainties on the performances under cyclic loadings, due to the degradation of the strength and stiffness under tension for the occurrence of instability problems in compression.
The current paper deepens such key issues, presenting the numerical simulation of some literature experimental tests conducted on CBX frames subjected to monotonic and cyclic loads both in presence and in absence of vertical loads.
The refined FE structural models of the study systems are developed through the software ABAQUS v6.13-1. The models set up have provided a very good replication of both monotonic and hysteretic behaviours in terms of strength, stiffness, ductility and energy dissipation. They are powerful analysis instruments to perform parametric studies, aiming at detecting the main factors affecting the cyclic structural behaviour, thus leading towards appropriate design criteria
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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