1,720,992 research outputs found
In-plane flexural behavior of hollow brick masonry walls with horizontal holes
No full textRecent seismic events proved that buildings built with hollow brick masonry walls performed quite poorly when subjected to horizontal actions. To provide insights, an experimental study was conducted to evaluate the flexural behavior of existing slender masonry walls built with clay hollow bricks with horizontal holes and cement-based mortar. Two full-scale specimens were designed and built to exhibit an in-plane rocking behavior when subjected to cyclic horizontal loads such as those induced by an earthquake; the pivotal aim of the experimental test is to assess the actual ductility of such a mechanism for this specific wall typology. The test results show that, unlike other masonry wall typologies exhibiting ductility in the case of in-plane flexural mechanism, this construction typology performs quite poorly under horizontal loads also in the case of rocking, with very little deformation capacity, which reduces by increasing the compressive strength of the mortar. A sudden failure was observed for quite reduced drifts in the experimental tests; failure was associated with the brittle crushing of the pier toe, in which compressive stresses were concentrated. The brittle collapse mechanism also entails the inability of the wall to further sustain the vertical loads, once the ultimate in-plane flexural capacity is reached. A numerical study was carried out; the finite element model was validated against the experimental results. The comparative assessment showed that the finite element model accurately predicts the structural behavior, lateral strength, and failure mechanism of the specimens. Parametric analyses on the vali-dated finite element model (FEM) were carried out to further investigate the structural behavior of different wall layouts or mechanical properties. Finally, a simplified bilinear behavior-curve is proposed to model the flexural response of slender walls, which can be specifically implemented when addressing an equivalent frame approach in the seismic vulnerability assessment of existing buildings built with the analyzed construction typology
Numerical Study of a Cold Formed Steel Panel Assembly for Seismic Retrofit of RC Buildings
No full textIl presente lavoro ha l’obiettivo di approfondire il comportamento di pannelli CFS impiegati come
sistemi sismo-resistenti a partire da una campagna sperimentale condotta presso il Nagoya Institu-
te of Technology (Nagoya, Japan). In particolare, sono stati sviluppati modelli ad elementi finiti a
complessità ridotta per simulare numericamente il comportamento nonlineare di un pannello in
scala reale. Attraverso analisi parametriche sono state dedotte indicazioni utili a calibrare il mo-
dello numerico per varie configurazioni geometriche del pannello stesso; inoltre, è stato studiato il
comportamento di più pannelli accoppiati ed è stata valutata preliminarmente l’efficacia
dell’impego del pannello considerato come rinforzo sismico in un edificio esistente.Starting from an experimental campaign conducted at the Nagoya Institute of Technology (Nago- ya, Japan), this work aims to investigate the behaviour of cold formed steel (CFS) panels used as seismic force resistant systems (SFRS). Simplified finite element modelling strategies have been developed to numerically simulate the nonlinear behaviour of a full-scale panel. Parametric anal- yses were conducted to derive useful indications on how to calibrate the numerical model for dif- ferent panel layouts. The coupled behaviour of multiple panels is investigated and the effective- ness of the considered CFS panel assembly as a seismic retrofit is preliminarily addressed
Intervento di riqualificazione integrata strutturale energetica ed architettonica di edifici residenziali in ottica LCT
No full textNegli ultimi anni in Italia si sono investite ingenti risorse per riqualificare il patrimonio edilizio esistente, del quale circa l’85% è stato costruito prima degli anni ‘90 e manifesta importanti carenze energetiche, strutturali ed architettoniche. Ciononostante, come testimoniano anche i dati sugli interventi che hanno sfruttato gli incentivi nazionali, si tende sempre a adottare un approccio molto settoriale alla ristrutturazione, spesso focalizzato solo sugli aspetti energetici e architettonici, per perseguire benefici tangibili di riduzione delle spese energetiche, trascurando le carenze strutturali e quindi i benefici non tangibili legati alla sicurezza sismica. Tuttavia, sostenibilità, si- curezza e resilienza non possono essere perseguiti indipendentemente e questi sforzi per raggiungere gli ambiziosi obiettivi di decarbonizzazione entro il 2050 possono rivelarsi un’occasione persa qualora non si persegua la strada degli interventi integrati.
Nell’articolo viene presentata una soluzione di intervento integrato per la riqualificazione di un quartiere di edilizia residenziale pubblica degli anni ‘70, composto da 5 edifici con struttura in c.a. di 4 piani ciascuno.Enormous resources are invested in Italy to renovate the existing building stock; 85% of the exist-
ing building was built before the 1990s and shows significant energy, structural and architectural
deficiencies. Despite this scenario, data on interventions which exploited the national incentives,
are showing a very sectorial approach to the renovation, often focused on energy and architectural
aspects only, to pursuit tangible benefits of reduction of the energy bill, while neglecting structur-
al deficiencies and thus un-tangible benefits related to seismic safety. However, sustainability,
safety and resilience cannot be pursued independently and the relevant effort to reach ambitious
targets of decarbonization by 2050 may be a missed chance, unless a deep and systematic inte-
grated approach on the built environment is undertaken.
In this paper, an integrated retrofit solution is proposed for the deep-retrofit of a 1970s social-
housing neighborhood, made of five 4-story RC buildings
An updated multi-criteria decision-making method for the sustainable renovation of buildings including environmental, economic and social life-cycle metrics
No full textThe ambitious targets of carbon emission reduction set worldwide for the coming years entail the commitment of structural engineers towards the sustainable renovation of existing buildings. The life cycle thinking (LCT) approach offers a holistic perspective for the design of sustainable retrofitting strategies. It envisages the reduction of the environmental impact at all building life cycle phases, while also addressing economic and social issues. Multi-criteria decision-making (MCDM) approaches support the choice of optimal retrofitting solutions, thus being relevant tools for boosting the actual adoption of LCT in current practices. In this study, a previously proposed MCDM approach is enriched with additional LCT-inspired decision parameters (module D beyond-life impacts, environmental payback period, invasiveness), and is then scrutinised and discussed through its application to a case-study building. Four integrated retrofitting scenarios are investigated using state-of-art seismic loss and energy performance assessment methods, including four different types of exoskeletons, made of timber, steel, and concrete. The end-to-end integrated assessment shows that the inclusion of additional LCT-inspired decision criteria effectively favours LCT-based retrofitting interventions over more traditional ones
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
Diagrid Exoskeletons for the Retrofit of RC Buildings. Holistic sustainable solutions to renovate post world war II RC buildings in a Life-Cycle Perspective
Full text linkEnormous resources are being invested in Europe to foster environmental, economic, and social sustainability; however, such relevant effort to reach ambitious targets may be a missed chance unless a deep and systematic intervention on the built environment is undertaken to target sustainability, safety, and resilience at the same time.
This thesis contributes to the scientific debate, focusing on holistic renovation from outside of reinforced concrete buildings by embracing a life cycle perspective.
Within such a new perspective, new technology options are needed; among the possible retrofit solutions, the diagrid structures as an innovative strengthening technique from outside are investigated.
First, a design procedure for elastic diagrid is proposed; then, a parametric evaluation of the retrofitted system through a simplified 2 DOF system is conducted and a set of design spectra are defined to derive the optimal retrofit parameter for RC buildings. Finally, a reference case study is developed to assess and validate the procedure
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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