1,720,997 research outputs found
Linear and Not-linear Models for the S. Francis Basilica in Assisi Under the Seismic Events of the 26th September 1997
No full textSPALLING AND TENSION STIFFENING IN HEAT-EXPOSED MEMBERS MADE OF SELF-COMPACTING CONCRETE
No full textHeat-induced damage, surface scaling and cover cracking always occur ??? with different severity - in R/C members subjected to a fire. Hence, bar-concrete bond in general and cover integrity in particular are at risk in fire, with consequences that can span from the loss of anchoring ability and tension stiffening to cover spalling, followed by the exposure of the reinforcement to the flames. In this research project, concrete spalling and tension stiffening are addressed, the attention being focused on corner spalling in reinforced and unreinforced prismatic specimens in the former case, and on reinforced tension members in the latter case. An experimental procedure to assess concrete sensitivity to spalling is proposed as well. Though very different in their nature, concrete spalling and tension stiffening are investigated within the same project, because (a) the same prismatic specimens are firstly subjected to a rather severe temperature-time ramp to provoke spalling and later to sustained high temperature to induce a generalized damage in the concrete; and (b) the bars placed in the corners are the most exposed to the risk of spalling and to the loss of bond, to the detriment of tension stiffening. Twenty one prisms made of SCC (target strength fc = 50, 80 and 90 MPa) were
put inside an electric furnace at 750°C to investigate spalling (9 unreinforced and 11 reinforced with a single bar totally embedded in the concrete). Later, the reinforced prisms were cleared of the concrete at their extremities, to allow the application of opposite tensile forces and to investigate tension stiffening. On the whole, the spalling tendency was rather weak, with 10% (20%) of the specimens exhibiting severe (light) spalling, while residual tension stiffening appeared to be still effective in only 50% of the reinforced specimens, where bond stiffness exhibited a roughly linear relationship with the residual compressive strength of the concrete
STRUCTURAL VIBRATION CONTROL BY TMD'S USE
Full text linkThe paper refers the use of Tuned Mass Dumper (TMD) in different constructions recently built in Italy to improve their serviceability structural performances. In two footbridges and a new tall building the dynamic behaviors are analyzed in the two conditions: without and with TMD. The structural analysis show the improvements in the Serviceability Limit State (SLS).
In the footbridge cases the use of the TMD allows the control of the deck vibrancy, either in the daily use and in extreme overcrowding case; in the tall building case the improvements are appreciated in relation to a greater comfort for the occupants due a better wind structural response
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
State of the art and recent applications of self-healing concrete
No full textSustainability in the field of civil engineering is becoming increasingly relevant. The sustainability of buildings and structures is strongly influenced by the decision-making process during the design phase, so it is becoming of the utmost importance the need to start coping with sustainability issues from the design stage. This with the aim of obtaining a final product of featuring high quality, preserving both the environment and people. Building performances should be maintained over time in order to avoid interventions of repair or demolition, which represent a “bunder” to the society, both in economic terms and environmental impact. In the field of construction, the concept of durability is closely related to sustainability.
The use of materials with the ability to repair themselves (self-healing materials) without outside intervention reduces the need for repair, which leads to extend the building and structure service life. Moreover, even though the initial costs are generally higher, these materials are an interesting option in the world of engineering construction since the future life cycle cost very strongly benefit from their use.
Concerning reinforced concrete structures, it well-known that they are subject to various damages (natural or accidental) that lead to concrete cracks. This type of damage if not repaired can lead to corrosion problems leading to a rapid deterioration. Therefore, self-healing concrete of the structure performance as a whole can be very useful in any type of structures. Moreover, self-healing concretes could be used also in combination with fibers to enhance their effectiveness.
Notably researches of self-healing concretes are still very recent. In fact, significant developments were observed in this field only in the last 10-15 years. Therefore, there is a strong need to address further studies and research in this area to better understand the potential that these materials can offer to the construction sector. A good starting point to address new research is to make a deep literature review on this subject in order to clarify what is known and what gaps still require further studies
A TMD APPLICATION IN THE SEISMIC IMPROVEMENTS OF AN HISTORICAL CHIMNEY
Full text linkThe paper analyzes the seismic improvement of an historical masonry chimney by the tuned mass dumper (TMD) application.
The chimney was built at the beginning of XX century in the northern region in Italy and the mechanical characteristics of the masonry, in terms of elastic modulus and compressive strength, used in the finite element models (FEMs) has been determined by a set of experimental tests. A first FEM is implemented by element beam (FEM 1) a second FEM is implemented by solid elements (FEM 2); in both, two configurations are studied: the chimney without TMD and the chimney with TMD. By a time history analysis the main characteristic of the TMD in the terms of mass, stiffness and damper values are valued and optimized for different positioning of the oscillating mass. Finally, a structural solution for the support of the TMD is proposed
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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