1,721,002 research outputs found
Seismic behaviour of a bracing system for LWS suspended ceilings: Preliminary experimental evaluation through cyclic tests
No full textThe results of a preliminary experimental study carried out to evaluate the seismic behaviour of a bracing system, designed to reduce the seismic vulnerabilities in lightweight steel (LWS) suspended ceilings, are presented in the current paper. The experimental investigation involved 12 cyclic tests on the bracing system carried out according to FEMA 461 loading protocol. A special test set-up for a universal testing machine was designed to test the system under two different directions of the horizontal seismic action, which could cause one or two braces of the bracing system to act as an element under tension. Test results were analysed in terms of strength, stiffness and damage phenomena. The study also demonstrates that a preliminary evaluation of the experimental cyclic response of a bracing system for LWS suspended ceilings under horizontal seismic actions can be performed by using a universal testing machine. Two case studies were developed in order to give preliminary information about the evaluation of the maximum ceiling area that a single bracing system can cover. The two case studies are residential reinforced concrete six-storey buildings located in two different geographical locations in Italy: Naples and L'Aquila, which are characterized by medium-high (0.17 g) and high (0.26 g) intensity of seismic loads, respectively. Based on the assumption of a weight for the ceilings in the range from 50 to 150 N/m2, a ceiling area ranging from 5.5 to 32 m2 was defined as the maximum area that a bracing system can cover
Behavior factor evaluation of CFS wood sheathed shear walls according to FEMA P695 for Eurocodes
No full textCold formed steel (CFS) wood sheathed shear walls are one of the most often used type of shear walls applied as the main lateral force resisting system (LFRS) in a lightweight steel (LWS) building. This paper evaluates the behavior factor used in the seismic design according to Eurocodes for buildings equipped with CFS wood sheathed shear walls as the main LFRS. FEMA P695 methodology is used to evaluate the behavior factor. A set of archetypes are selected and designed, which reflected the applicable building heights, seismic hazard and occupancies for LWS buildings in Europe. Nonlinear three-dimensional finite element (FE) models of building archetypes are developed in OpenSees software using the individual shear wall models, which are calibrated on results from tests on individual shear wall specimens. The resilience of building models against collapse is checked by analyzing the models using lateral static (pushover) and incremental dynamic analysis (IDA). Uncertainties arising from test and design information, numerical modelling and archetype response variability to different ground motions is also taken into account. Based on the collapse performance evaluation results, a value of 2.5 for behavior factor, used in the design, is found to provide appropriate level of safety against the collapse in LWS buildings equipped with CFS wood sheathed shear walls
Development and Calibration of Hysteretic Model for CFS Strap braced stud walls
No full textCold-formed steel (CFS) members in buildings are in use for decades, but their earthquake performance remained unexplored, until recently. Eurocodes, which provide common approach for the design of buildings in Europe still lack the information on seismic design of CFS structures. However, for the last few years, University of Naples “Federico II” CFS research group is dedicated in investigating their seismic performance. One of the focus areas is characterizing seismic behaviour of CFS strap braced stud walls. This paper presents a generalized approach adopted in simulating hysteretic behaviour of these walls under cyclic load in OpenSees software. Numerical models are developed and calibrated on the basis of available experimental results
Seismic design criteria for CFS steel-sheathed shear walls
No full textThe current European earthquake standard EN1998-1 does not provide the seismic design criteria for cold formed steel (CFS) steel-sheathed shear walls, limiting their use as a lateral force resisting system in lightweight steel buildings. In order to overcome this lack of guidelines, a specific study has been performed to extend the applicability of the Effective Strip Method (ESM), given in North American standard AISI S400 to EN1998-1. The method evaluates the shear resistance of steel-sheathed shear walls and it is permitted only in USA & Mexico as an alternative to tabulated shear resistance for predefined wall configurations. In order to further validate its scope of application, it was applied to additional available experimental results of walls tested in Canada. Only for some configurations, the ESM does not give acceptable predictions. Furthermore, the ESM was applied following the European approach, to make its use possible in context of European seismic design methodology. The overstrength factor for the design of non-dissipative elements was evaluated. Based on the results, it is concluded that the ESM could be appropriate for the evaluation of resistance of steel-sheathed shear walls in Eurocodes
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
NUMERICAL EVALUATION OF THE BEHAVIOUR FACTOR OF LIGHTWEIGHT STEEL LATERAL FORCE RESISTING SYSTEMS ACCORDING TO FEMA P695
No full textSeismic design regulations rely on certain factors to reduce the earthquake actions due to inherent ductility and overstrength of the lateral force resisting systems. The behaviour factors given in Eurocodes are one such example, which when applied during the design process will ensure the life safety performance level of a building. Light-Weight Steel (LWS) structures fabricated with Cold Formed Steel (CFS) profiles are increasingly widespread in earthquake prone regions, however the current in practice edition of Eurocodes fails to acknowledge their seismic performance by not providing behaviour factors for them. The study presented herein addresses this issue by evaluating behaviour factor for the two commonly used LWS systems: CFS strap braced walls and CFS shear walls with gypsum board sheathing through FEMA P695 methodology. For each type of system, a set of archetypes, which represent a range of design parameters and building configurations are designed following the capacity design approach and their response is idealized by nonlinear numerical models. The performance of archetype models is evaluated systematically through the static pushover and the incremental dynamic analysis under a suite of forty-four normalized and scaled earthquake records, representing the probable seismic hazard to the buildings. Finally, by calculating the collapse probability while also considering the uncertainties from various sources, the suitability of a trial value of the behaviour factor used in the design phase of archetypes is evaluated. Based on the results, it is concluded that a behaviour factor of 2.5 and 2.0 for CFS strap braced walls and CFS shear walls with gypsum board sheathing is appropriate
Variations on the Author
Get PDF“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
Get PDFWe 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
Seismic design criteria for CFS steel-sheathed shear walls
No full textThe current European earthquake standard EN1998-1 does not provide the seismic design criteria for cold formed steel (CFS) steel-sheathed shear walls, limiting their use as a lateral force resisting system in lightweight steel buildings. In order to overcome this lack of guidelines, a specific study has been performed to extend the applicability of the Effective Strip Method (ESM), given in North American standard AISI S400 to EN1998-1. The method evaluates the shear resistance of steel-sheathed shear walls and it is permitted only in USA & Mexico as an alternative to tabulated shear resistance for predefined wall configurations. In order to further validate its scope of application, it was applied to additional available experimental results of walls tested in Canada. Only for some configurations, the ESM does not give acceptable predictions. Furthermore, the ESM was applied following the European approach, to make its use possible in context of European seismic design methodology. The overstrength factor for the design of non-dissipative elements was evaluated. Based on the results, it is concluded that the ESM could be appropriate for the evaluation of resistance of steel-sheathed shear walls in Eurocodes
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