1,721,016 research outputs found
Special issue on building and infrastructure response to ground movement: Bridging the gap between geotechnical and structural modelling of SSI
No full textIl ruolo dei fattori geomorfologici nell'innesco e propagazione delle frane del 30 aprile 2006 sul Monte di Vezzi (Ischia, Italia) - The geomorphic control on the initiation and propagation of the Mt. di Vezzi landslides (Ischia island, Italy) occurred on 30th april 2006.
No full textThis paper summarises the first results of a geomorphological study we carried out in the area struck by the 30th April 2006 landslides, in Ischia island. This study aimed at the documentation of the landslide traces, and at providing new evidences on the role played by the pre-existing landforms in the location of the source areas, in landslide propagation and motion, and in the distribution of localized and distal accumulation. This was done through field surveys (started soon after the events), and by analyses of aerial photographs, topographic maps and of DTM. Besides the reconstruction of the main stages of landscape evolution of the Ischia sector including the area struck by the landslides, a detailed landscape analysis of the latter area was carried out. This allowed classification of the study area in terms of dip values and land systems, and identification of minor geomorphic elements which compose each unit. Afterwards, the relationships among the features of the single units/elements and landslide initiation, propagation and accumulation were investigated. Although the Ischia case provided a small population of phenomena, it they may be considered as a representative study case for the pyroclastic earth slides which have been affecting the Campania region in the last decennia. The integration of the collected evidences with those deriving from the pre-existing record of cases highlights, above others, the important control exerted by steep elements breaking the hillslopes not only on initiation, but also on propagation of the landslides. The recognised role of subvertical elements suggests the crucial importance of their detection in landsliding susceptibility assessment. As a consequence, in cases where the presence of such elements is not proved but only inferred, the susceptibility threshold slope angle should be prudentially lowered
Tunnel–framed building interaction. Comparison between raft and separate footing foundations
Full text linkIn this paper, the influence of the foundation configuration (raft or separate footings) on tunnel–soil–framed building interaction is investigated using geotechnical centrifuge testing. Tunnelling-induced soil movements and deformation fields, framed building displacements and structure shear distortions (with associated modification factors) are illustrated. Framed building stiffness and footing bearing capacity are also evaluated experimentally. Results show that the foundation configuration plays an important role in determining the ground response to tunnelling, affecting soil displacement fields, as well as the distribution of soil shear and volumetric strains. In particular, foundation settlements and differential horizontal displacements are larger for separate footings compared to raft foundations. The effects of building width, weight and eccentricity (with respect to the tunnel) on foundation settlements and structural distortions are quantified for separate footings and contrasted against results for raft foundations. The modification factor of the maximum building shear distortion is linked to the relative soil–building shear stiffness; interestingly, for buildings with similar values of relative stiffness, the level of shear distortion within framed buildings is lower for separate footings than rafts
Role of Footing Embedment on Tunnel-Foundation Interaction
No full textThis technical note investigates the effect of footing embedment depth on tunnel-structure interaction using geotechnical centrifuge testing. A 2-story framed building on separate footings, either resting directly on the surface or embedded in the soil, and subjected to tunneling-induced displacements is modeled. Measurements of the displacements of the footings and underlying soil, ground deformations, and structural distortions are presented. Results show that footing embedment increases foundation differential settlements and horizontal displacements, thereby causing a greater level of distortion within the frame. Furthermore, the embedded footings result in a larger magnitude of ground displacements and shear strains of the soil. Finally, modification factors and relative stiffness parameters are presented, indicating a greater effect of the embedment on horizontal deformations than the angular distortion of the bays
An equivalent beam approach for assessing tunnelling-induced distortions of frames with infills
No full textThis paper presents an approach to evaluate the response of low- and medium-rise frames with continuous foundations, either with or without infills, to tunnelling employing an equivalent beam with a behaviour dominated by shear deformations. Simplified soil-structure interaction models, consisting of a beam resting on an elastic continuum half-space, are compared against advanced three-dimensional analyses in which the tunnel, the soil, and the building are explicitly modelled. In the simplified approach, the frame is schematised as a Timoshenko beam and reliable procedures to estimate both bending and shear stiffness are discussed. In the refined modelling strategy, an advanced elastoplastic constitute law is employed, capable of reproducing fairly well the soil response to the excavation for increasing values of volume loss, while the full geometry of the structure is considered. First, the results of the proposed numerical approaches are compared in terms of tunnelling-induced foundation displacements, bay deformations and maximum tensile strains in the infills. Then, for the infill panels, the reliability of estimating the maximum tensile strain from the angular distortion of the frame bays is assessed. Finally, a meta-model is proposed to predict the maximum angular distortion based on greenfield settlements, eccentricity, and relative soil-structure stiffness
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
Numerical modelling of framed structures with masonry infills affected by tunnelling-induced deformation and damage
No full textThe paper describes a numerical approach aimed at investigating the response of framed structures with masonry infills to tunnel excavation in sand. The numerical model, analysed with the Finite Element method, includes the soil, the tunnel and the framed structure with infills. It proved its capability in reproducing the soil response at different values of the volume loss and the principal soil-structure interaction mechanisms, including sliding and development of a gap at the soil-foundation interface. The results are summarised in terms of angular distortion values for each bay as well as local tensile strains in the masonry infills. Finally, the efficiency of angular distortion models in predicting the maximum tensile strain of the infills is also evaluated
- …
