1,722,335 research outputs found
A simplified displacement-based hybrid approach for the design of geosynthetic-reinforced earth walls
No full textDesign criteria for geosynthetic-reinforced earth walls are usually based on simplified limit equilibrium approaches, taking into account ultimate conditions both with respect to soil strength and reinforcements’ resistance (tensile and pull-out). Convenient values of partial safety factors are then introduced to get a safe structural dimensioning. The stability of internal failure mechanisms is however based on the mobilization of soilgeosynthetic interface shear stresses and the reinforcement action should rather be computed as a function of the current internal displacements within the wall. In the paper a simplified displacement-based hybrid approach is introduced, combining traditional limit equilibrium analyses of internal failure mechanisms together with displacement controlled non-linear pull-out analyses of the reinforcements. A consistent relationship between the safety factor and the performance of the wall (i.e. façade displacement) can then be derived, providing the designers of an objective tool to optimize the design choices and to run consistent structural safety checks
The Role of Geotechnical Engineers in Sustainable Construction Processes: A Regard to Soil-Structure Interaction Problems
No full textSustainability-related issues became more and more important in these last decades owing to the increasing awareness in modern societies of the limitedness of the resources at the global planetary scale. Environmental resources, in particular, play a key role in this perspective since (i) they are hardly recoverable and (ii) their uncontrolled consumption may trigger complex chains of events, with potentially catastrophic consequences. In technological advanced societies like ours, the Engineering contribution is essential to correctly deal with these problems, and engineers (both scientists and practitioners) cannot disregard these topics. With reference to Built Environment, the contribution of Geotechnical Engineers can in particular give relevant positive benefits, since Geotechnical works very often involve large (or very large) soil volumes, and are in general conceived as long-lasting (if not permanent) interventions. In the paper, with specific reference to soil-structure interaction problems, some general considerations are presented, by putting in evidence the contribution that Geotechnical Engineers can give to the design process, since its early stages. Several examples of recent case studies will be reviewed, with reference to the protection of historic and cultural heritage, to slope stabilizing interventions, to the protection of strategic infrastructures like buried pipelines, in particular by employing innovative upscaling approaches based on the “macroelement” concept
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
Experiments and modelling of horizontal loading tests on small-scale foundations in sand
No full textThe accurate prediction of settlements of shallow foundations under operational conditions is still an open issue for both scientists and engineers, in particular in the case of complex loading conditions (e.g. combined vertical and horizontal loads). The complexity of the soil mechanical response and the difficulty in managing a multiscale problem (ranging from the local scale of the soil representative elementary volume to the macro-scale of the structure) makes a rigorous modelling of such problems particularly demanding for standard numerical tools such as three-dimensional finite-element codes. In this perspective, the well-known macroelement approach may represent a valid simplified approach, capable of overcoming these limitations and allowing a comprehensive description of both serviceability limit state and ultimate limit state of such systems, particularly useful even for practitioners. In the paper, based on a small-scale 1g experimental campaign on a strip foundation, the effect of embedment is investigated over horizontal loading paths at a constant vertical load. In particular, relatively low vertical stress values are considered for the foundations, as it often happens in real structures under usual working conditions. A simple macroelement plastic model, based on a strain hardening law with non-associated flow rule is then proposed and validated over the available experimental data
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
Studio sperimentale in piccola scala del ribaltamento di apparati radicali semplificati in condizioni di parziale saturazione
Full text linkUn approccio numerico semplificato per la stima dell’azione di sostegno di pali in pendii potenzialmente instabili
No full textAn innovative “geo-carpet” system as a countermeasure against local scour at bridge piers: small-scale test results
No full textLocal scour around bridge piers is one of the most diffused causes of failure for river bridges since it considerably modifies the geometry of the riverbed around the foundation. Countermeasures have been proposed in terms of both bed armoring and flowaltering devices. In this field, the use of Geosynthetics can provide innovative solutions, with environmental, economic and technological benefits compared to more traditional approaches. In the paper some flume experiments, run in clear-water flow conditions on a circular pier in a homogeneous granular riverbed, are described. The tests included four runs where the area around the pier was covered with innovative “Geo-carpet” systems made by plastic nets with different mesh size, and one reference test on an unprotected pier. The results, at least for a single hydro-dynamic condition, showed the efficiency of the Geo-carpets on the reduction of the scour depth and volume, and pave the way to future experiments investigating different geometries and flow conditions (including live-bed scour)
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