1,720,963 research outputs found
Progressive collapse of 2D framed structures: An analytical model
No full textAn analytical model for the collapse of regular 2D framed structures after column removal is presented. Under simplified conditions, we obtain closed form expressions of the upper and lower bounds of the collapse loads, which depend on the activated collapse mechanism. A quantitative geometric/mechanical parameter is also determined that, for a given initial damage, indicates what collapse mechanism is triggered. For several scenarios we evaluate the resistance against progressive collapse initiation as the ratio between the dynamic collapse load after damage and the static collapse load before damage. Our results are compared to data from dynamic nonlinear simulations. The analytical procedure developed here suggests a strategy for a preliminary robustness-oriented design, involving specific solutions in terms of redundancy, compartmentalization, and mechanical properties of columns and beams. © 2013 Elsevier Ltd
The Kent Tensegritree project
Full text linkThe development of the design of a new tree-like tensegrity sculpture, the Tensegritree, is described. The Tensegritree will provide a permanent memorial celebrating the 50th Anniversary of the University of Kent, and the 10th Anniversary of the founding of Kent School of Architecture. The tree-like conceptual form emerged from a workshop with students at the University of Kent; based on the concept, a final form was developed, simplified, optimized and realized: The final sculpture will have a height of 7 m, and a diameter of 12 m, and is due to be installed in July 2015
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
On the influence of corrosion levels in the dynamic behavior of pretensioned concrete structural elements
No full textCorrosion of internal reinforcements represents a serious issue in prestressed concrete structures, as it progressively decreases the load bearing capacity of components, hence contributing to reduce the service life of the whole structure and potentially inducing unexpected and uncontrolled cracking phenomena. A proper assessment of the health status of a structural element is the key priority of any Structural Health Monitoring (SHM) system. As SHM systems are finally getting the credits they deserve, given their relevance in keeping structures monitored and hence in contributing to people life safety, the focus has shifted towards the development of automated approaches to promptly detect incipient damages potentially jeopardizing the structural integrity of the target system. Within this context, this chapter, which describes a part of a wider research program targeted to the development of robust strategies for SHM of civil structures, aims at discussing a preliminary study carried out to identify the potential correlation between corrosion levels in pretensioned concrete elements and their dynamic behavior. Several pretensioned concrete beams of the same geometry (cross section 200 × 300 mm; total length 3700 mm) have been subjected to an artificial corrosion process that was induced through electrolytic cells by dipping the beams within a 3% saline solution, up to half of the height of the cross section. Four-point bending tests were performed up to failure. Dynamic impact tests were also performed to identify any eventual variation in terms of dynamic behavior of the beams. The chapter shows that increased corrosion induces wider changes in the dynamic behavior of the structural elements
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
Exploring Bridge Structural Response similarities: Data-Driven SHM Through MEMS Clinometer Clustering over a Network of 25+ Reinforced Concrete Bridges
No full textStructural Health Monitoring (SHM) employs a combination of mechanism analysis, monitoring technology, and data analytics to identify, classify, and assess the significance of structural conditions such as sudden or cumulative damages. In recent years, the spread of IoT-based continuous SHM systems has enhanced the control of the functionality and operational integrity of bridges supporting an informed proactive maintenance, management, and decision-making processes associated with bridges. With the growing availability of big data across a network of similarly monitored structures, there is an increased interest and possibility of conducting a more in-depth analysis to identify commonalities or differences between homogeneous structural schemes and typologies. This interest arises from the dual need to optimize the utilization of monitoring systems over a widespread network and to address the challenge that in-service bridges often lack data from damage scenarios, with existing methods struggling to achieve real-time detection. This goal, along with optimizing the monitoring strategy, could be achieved by grouping similar structures in the network into macro-classes, with a 'master' structure serving as a model for the others. This paper explores the feasibility of this approach and aims to establish a valid criterion for identifying macro-classes within an infrastructure network. The study involves the analysis of the static response of over 25 reinforced concrete and prestressed bridges/viaducts built in Italy, sharing similarities in static schemes and construction methods. The analysis relies on data gathered from the execution of static load tests, proposing a tool for optimizing the monitoring strategy across a network of bridges
Concrete Bridges Continuous SHM Using MEMS Sensors: Anomaly Detection for Preventive Maintenance
No full textBridge infrastructures in Europe are facing ageing, progressive damaging processes, change of traffic loads as well as climate change effects; as such, a sound diagnostics process based on the analysis of accurate information acquired from monitoring systems is a key enabler to support the application of preventive maintenance plans and to guide efficient decisions on repairs or strengthening. The fast-paced development of cheaper but reliable devices has allowed to collect a huge amount of data to deepen the knowledge of the structural behavior over time of existing structures under service conditions. This paper shows the use of MEMS sensors, both clinometers and accelerometers, for continuous structural health monitoring on concrete bridges. A dense sensing monitoring approach is applied, and data are analyzed and compared in near-real time with a threshold set based on an updated reference FE model of the bridges. A case study is presented, where anomaly detection algorithms based on key performance indicator evolution in time have efficiently identified and localized damages triggering repeated proactive maintenance interventions. Attention is given to the seasonal influence on both the static and dynamic response of the bridges, and on the misleading effects on the damage detection and diagnostics processes. This approach is part of a wider framework aimed at an industrial application of SHM, in which the specific aspects covered in this paper have been identified and analyzed on multiple similar concrete bridges under continuous monitoring, of which evidence is provided
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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