1,720,958 research outputs found
Influence of lateral load distribution in estimation of target displacement and capacity demand by pushover analysis
No full textTwo simplified adaptive load patterns for conservative estimation of seismic demand in 2D frames by pushover
analysis are presented. The influence of load pattern in assessment of target displacement and distribution of
demand along the height of the structure is investigated by comparing results of non linear history analysis, and non linear static analysis for eccentric braced frames. Numerical analyses show that the proposed load patterns provide safe estimation of the seismic response more accurately than load patterns proposed by seismic code
Influence of lateral load distributions on pushover analysis effectiveness
Full text linkThe effectiveness of two simple load distributions for pushover analysis recently proposed by the authors is investigated through a comparative study, involving static and dynamic analyses of seismic response of eccentrically braced frames. It is shown that in the upper floors only multimodal pushover procedures provide results close to the dynamic profile, while the proposed load patterns are always conservative in the lower floors. They over-estimate the seismic response less than the uniform distribution, representing a reliable alternative to the uniform or more sophisticated adaptive procedures proposed by seismic codes. © 2008 American Institute of Physics
Sul controllo del meccanismo di collasso di controventi eccentrici
No full textThe effectiveness of different non-linear static procedures, for the detection of the collapse mechanism of eccentric braced frames, is investigated. EBFs introduced into truss frame structures are considered. For such a typology of structures, plastic deformations are concen-trated in a single resistant element at each floor, greatly increasing the risk of the formation of soft storey mechanisms, even if the structure is designed according to the capacity design. The results of different non-linear static procedures are compared to those obtained by incremental dynamic non-linear analysis, considering a meaningful set of artificially generated stationary accelerograms, compatible with a target spectrum
Non-linear Correlation Coefficients for pushover analysis
No full textAiming to put forward an improvement on Multimodal Pushover Analysis, a modified version of the
modal correlation rule that takes into account the non-linear behavior of structures is proposed. The modification
is primarily based on using the correlation coefficients consistent with the mechanical and dynamical properties
of the hysteretic oscillators utilized in the MPA method, i.e. determined taking into account the second order
statistics pertinent to the non-linear oscillators. Initially, the new correlation coefficients are evaluated by Monte
Carlo Simulations (MCS), assuming a spectrum-compatible representation of the seismic input. The results of a
large numerical parametric analysis are shown. Moreover, analytical expressions for the proposed correlation
coefficients are derived on the basis of the stochastic linearization technique. Lastly, the results provided by the
modified MPA for a simple 2DOF system are compared with Non-linear Response History Analysi
Combination coefficients for modal pushover analysis
No full textConventional non-linear static analysis estimates the response peak value by evaluating the pushover
curve adopting a distribution of invariant forces proportional to the fundamental vibration mode. In order
to include the effect of higher modes, multi-modal push-over analysis has been proposed in literature. Nodal response peak values are obtained by combination of “modal” responses usually by the traditional CQC method, requiring cross correlation coefficients defined for linear systems. In this paper, the accuracy of correlation coefficients for linear systems in predicting the statistical correlation of hysteretic oscillator responses is investigated by the Monte Carlo Simulation conducted on non-dimensional non-linear oscillators. Furthermore, new correlation coefficients determined through a pertinent statistical linearization are introduced, and the results provided by the classical and the proposed approach for two illustrative frames are compared with non-linear time history analysis, showing the effectiveness of the new procedure
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
- …
