1,720,974 research outputs found
Strategies for structural modelling of CLT panels under cyclic loading conditions
No full textCross Laminated Timber (CLT) is an extensively used technology to build medium- and high-rise buildings, especially thanks to the rapidity of execution, environmental sustainability, and good mechanical performances. Since this material is presently employed also in seismic-prone areas, the assessment of numerical modelling strategies to reproduce the cyclic behavior of CLT-wall systems has become a relevant research topic within the structural engineering field. Two different modelling approaches can be adopted to model the seismic behavior of such systems: the phenomenological approach and the component-level one. After a comparative presentation of the two approaches, the paper focuses on the different strategies used to create reliable component-level models able to reproduce the CLT panel-connection system behavior both at the global and local level (i.e., in terms of force-displacement curve and cumulative energy, as well as uplift and slip displacements). The experimental tests carried out at CNR-IVALSA during the SOFIE project – after a preliminary phase of interpretation of the experimental dataset, necessary to identify the peculiarities of the test procedures – are used as a comparative basis to assess the quality of the numerical results. The obtained outcomes demonstrate that the component-level approach could be a feasible and reliable method to reproduce the CLT panel connection systems cyclic behavior, also at a local level, provided that the behavior of each individual component is properly calibrated
A coupled damage model for RC structures: Proposal for a frost deterioration model and enhancement of mixed tension domain
No full textThe coupled chemical-mechanical damage model developed by some of the authors was enhanced concerning both mechanical and environmental aspects. A more comprehensive representation of the mixed-tension domain was developed, together with the proposal of an innovative formulation to account for frost attack. The mechanical enhancement was validated by means of comparison with different experimental tests. Then the parameters of the proposed environmental model were calibrated by using a limited number of tests on concrete specimens under freeze-thaw-cycles. Afterwards it was used as predictive tool for simulating different series of tests and to evaluate the load-carrying capacity of a frost-damaged beam. © 2014 Elsevier Ltd. All rights reserved
Corrosion effects on the seismic response of existing rc frames designed according to different building codes
No full textDurability problems significantly affect the structural performance of reinforced concrete (RC) buildings: when exposed to aggressive environmental conditions, both steel reinforcing bars and concrete undergo relevant alterations of their mechanical performance (strength and deformation) leading to a general decrease of the bearing capacity of structural elements and, more in general, of the whole construction. Material deterioration can be responsible for the shift of the collapse mode from ductile/flexural mechanisms to brittle/shear ones in relation to the entity of corrosion attack, the materials used (both concrete strength class and reinforcement grade) and the structural details assumed according to the design. As well known, the Italian building stock is made up of structures realized, for the majority, without following specific seismic design features and to resist – mainly – gravitational vertical load combinations, until the introduction of the actual code after the dramatic earthquake event of L'Aquila 2008. For this reason, the deep knowledge of the structural performance of RC buildings realized neglecting (or simplifying) seismic action in presence of corrosion attack becomes a topic of relevant importance to determine possible solutions and improvement at section, element and whole building level. In the present paper, the effects of corrosion on two case study buildings designed following actual and past Italian codes for constructions (i.e. with and without respecting the capacity design approach) are then presented. The structural assessment in aggressive environmental conditions is performed adopting different entity and distribution scenarios of corrosion, taking into consideration the decrease of strength and deformation capacity of constitutive materials and the resulting loss of confinement affecting RC sections, allowing to determine the attainment of the ductile and brittle mechanisms and the modification of the structural performance
Enhanced N-V interaction domains for the design of CLT shear wall based on coupled connections models
No full textThe present paper proposes some enhanced models, with different levels of accuracy, for the design of monolithic CLT shear wall based on the definition of reliable N-V interaction domain. The basic assumptions and the novelty aspects of the proposed models are presented. In particular, the adoption of an elastic-perfectly-plastic constitutive law for the timber instead of an elasto-brittle one and the accounting for the coupled axial-shear behavior of the connection elements to derive N-V interaction domains are critically discussed. Moreover, two different methods are adopted for the linearization procedure of the connection load-displacement response. Four of the proposed models are design oriented, two representing a lower bound (more suitable for practitioners), and two representing an upper bound. One more model is developed, which is research oriented and based on hybrid force-displacement approach. The reliability of the different models is investigated by means of numerical analyses exploiting the ultimate failure condition of the materials both in terms of strength and displacement capacity. Finally, the N-V domains for some CLT shear walls are presented and the impact of the different basic assumptions on the results are discussed in comparison with both experimental and numerical literature results
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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