1,720,977 research outputs found
Seismic Behavior of Precast Buildings With Dissipative Connections
Full text linkRecent earthquakes in southern Europe highlighted that the connections of cladding panels to R.C. frames in precast buildings had a major role in the structural collapse. For this reason, there is an urgent need for a review of the design methods for these connections as well as for an improvement in the manufacturing technology. This article aimed to assess the efficiency of dissipative panel-to-structure and roof connections in R.C. precast buildings. A parametric study consisting of linear and non-linear analyses on one case-study building is performed. Different sensitivity analyses are performed varying their mechanical properties (i.e., stiffness, strength, and ductility) to analyze the behavior of the CP/frame connections. The study focuses on dissipative connections with an elastic–plastic behavior, placed between cladding panels (CPs) and frames in precast buildings with stacked horizontal cladding panels. The introduction of dissipative CP/frame connections implies the inclusion of panels in the global seismic resisting system. The “panels + frame” system highlights a high stiffness until the yield strength of the CP/frame connections is reached. The results, obtained from non-linear dynamic analyses (NLDAs), clearly show how the proposed connection improves the structural seismic performance. By contrast, this is no longer true for R.C. precast structures with flexible diaphragms, especially for intermediate columns, far from panels aligned to seismic action. In this case, significant and unexpected axial forces arise on out-of-plane connections between panels and columns. The integration of an efficient diaphragm is essential to prevent these critical issues both on intermediate columns and CP/column connections; it enables the dissipative capacity of the “panels + frame” system, and it significantly limits the forces and displacements of intermediate alignments. Unfortunately, the achievement of a rigid diaphragm is not always feasible in precast buildings. A possible alternative to activate dissipative capacities of the roof diaphragm with limited in-plane stiffness is the use of dissipative connections linking roof beams and main beams. The solutions described in this article can be applied both in the design of new buildings and for the seismic upgrading of existing ones with easy-to-install and low-impact applications
Applicazione delle metodologie geo-topografiche satellitari per lo studio di modelli matematici del geoide in ambito locale.
No full textUniversità di Padova, Dipartimento di Architettura, Urbanistica e Rilevamento
Caratterizzazione di un sistema per la riqualificazione integrata di edifici esistenti mediante prove sperimentali su campioni in scala reale
No full textCaratterizzazione sismica di una parete di taglio in acciaio-legno con innovativo sistema di controventamento
No full textQuesto lavoro descrive l'analisi strutturale di un nuovo telaio in legno modulare accoppiato con un pannello OSB e una lastra di gesso tamponata con tecnoprene, che conferiscono, nel piano, resistenza al taglio al telaio e permettono la realizzazione di pareti di taglio efficienti e dissipative. Il comportamento sismico previsto del sistema è stato confermato da prove sperimentali. Per definire le principali caratteristiche meccaniche del sistema sono stati condotti test di carico ciclico (quasi statico) secondo il protocollo della norma EN 12512. Infine, sulla base dei risultati di prova, è stato calibrato un modello numerico, al fine di caratterizzare il comportamento dinamico non lineare di un edificio preso come caso in studio e di stimare l'opportuno valore di fattore di struttura per questo sistema.This work discusses the structural analysis of a novel modular timber frame coupled with an OSB panel and a
tecnoprene plaster-infilled slab, which confer in-plane shear resistance to the frame and allow the realization of
efficient and dissipative shear walls. The expected seismic behaviour of the system was confirmed by experimental
tests. Quasi-static cyclic-loading tests were conduced according to EN 12512 protocol to define the main
mechanical properties of the system. Finally, a numerical model was calibrated on the basis of test results, in order
to characterize the dynamic non-linear behaviour of a case-study building and to estimate the suitable behaviour
factor value for this system
Seismic capacity of steel frames braced with cross-concentric rectangular plates: Non-linear analyses
No full textThe use of cross-concentric braced steel frames is still an effective way to realize earthquake-resistant buildings, thanks to the simplicity in the design and realization, assuring good strength, stiffness and ductility, provided that capacity design be fulfilled. Results from non-linear static and dynamic analyses of steel frames braced with cross-concentric rectangular plates are presented to discuss some significant design aspects that play a key role in the definition of the hysteretic dissipative response of such structures. Parametric cyclic analyses were performed to assess the peak- and post-buckling lateral strength and the dissipative capacity of a small- and a full-scale frame, varying the non-dimensional slendemess of the bracing plates. Then, results of incremental dynamic analyses of a one-, three-, six- and ten-storey building are discussed to evaluate the behaviour factor for this structural typology, as function of inter-storey drift. Results from the parametric and incremental analyses give the optimal range of non-dimensional slenderness of the bracing plates as a compromise between limited overstrength and good dissipative capacity and confirm the behaviour factor currently provided by Eurocode, relating it with an expected inter-storey lateral drift. (C) 2019 Elsevier Ltd. All rights reserved
Seismic and energy integrated retrofitting of existing buildings with an innovative icf-based system: Design principles and case studies
Full text linkThis work proposes an innovative integrated retrofitting system aiming to improve both the seismic and energy performance of existing reinforced concrete and masonry buildings. The system is based on engineered insulating concrete form panels, installed on the outside of existing buildings as a shell exoskeleton. A key major advantage of the proposed system is that it addresses the contemporary improvement of seismic and energy performances of existing buildings in a single installation stage, operating exclusively from outside of the building. The insulating formworks are ad hoc prefabricated in a factory on the base of the specific geometry of the existing buildings so as to greatly maximize the ratio between overall retrofitting benefits and costs and at the same time to simplify the installation procedures. The objectives of the presented research are, on one hand, to highlight the major structural issues that the system aims to address, and on the other hand to illustrate the main characteristics and combined benefits of the proposed retrofitting system. From a structural point of view, the proposed system is conceived to behave as a non-dissipative structure with regard to seismic actions, and the lateral strength and stiffness of the structural elements are designed accordingly. An analytical design approach is proposed and validated using the available data from an experimental test performed on a full-scale simple building. Moreover, numerical modeling strategies for the proposed system are illustrated for two complex case study buildings. The results of the analyses show a considerable increase in lateral stiffness of the retrofitted buildings that, considering the non-dissipative behavior of the elements, leads to a relevant reduction of seismic deformation demand on existing structural elements
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
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