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Correction to: A probabilistic investigation on the dynamic behaviour of pile foundations in homogeneous soils
No full textDue to proofing error, author surnames were reversed and should correctly read as: Lucia Minnucci, Michele Morici, Sandro Carbonari, Francesca Dezi, Fabrizio Gara, Graziano Leoni Original article has been updated
The Fragility of Link Slab Viaducts: Analysis of a Case Study in Central Italy
No full textRecent seismic events occurred in Central Italy drew the attention towards the resilience of the Italian road network, which is characterised by a significant number of old reinforced concrete bridges and viaducts. In this context, the fragility assessment of existing bridges is crucial, since their collapse or loss in functionality after earthquakes may lead to significant economic and social consequences. As a part of a more general study oriented to characterize the fragility level of the Central Italy bridge stock, this work focuses on the real case study of the Chiaravalle viaduct, which may be representative of a widespread class of reinforced concrete bridges in Italy: the viaduct is a continuous multispan bridge consisting of precast simply supported V-shaped beams connected by a continuous slab. A numerical model is developed in order to capture the failure mechanisms most likely to occur for this bridge typology subjected to seismic actions. A probabilistic assessment of the seismic response of the bridge is carried out by performing multiple stripe analysis, considering a seismic scenario consistent with the Chiaravalle site. Fragility curves, built by accounting for the main demand parameters and the relative limit states, provide useful insights about structural deficiencies of the system at hand
Innovative Fragility-Based Method for Failure Mechanisms and Damage Extension Analysis of Bridges
Full text linkThe seismic assessment of existing bridges is of the utmost importance to characterise the main structural deficiencies, estimate the risk, prioritise retrofit interventions, or estimate losses and repair costs in case of earthquakes. The above tasks require information on the damage mechanisms likely to occur as well as on the damage extent over the structure. Such types of information are generally not provided by classical fragility analysis, which is mainly focused on the evaluation of the global performance of the bridge. In this paper, a systematic probabilistic methodology for the evaluation of bridge fragility is proposed. The methodology aims at offering insight into the failure mechanisms most likely to occur and the evolution and extent of damage within the bridge structure. First, a mathematical description of the proposed analysis methods is given, then an application to a realistic case study—a reinforced concrete multi-span simply supported deck link-slab bridge—is provided to illustrate the applicability of the tool. A nonlinear 3D finite element model is developed, and a multiple-stripe (nonlinear dynamic) analysis is performed by using a stochastic bidirectional seismic input. The results highlight the suitability of the proposed methodology to reveal the main structural deficiencies, the relations among different failure mechanisms (involving piers, bearings, abutments, etc.), and the expected damage extent
Influence of the piers' height on the fragility assessment of Italian R.C. Link slab bridges
No full textRecent seismic events occurred in Central Italy drew the attention towards the resilience of the Italian road network, which is characterized by a significant number of old reinforced concrete bridges and viaducts. In this context, the fragility assessment of existing bridges is crucial, since their collapse or loss in functionality after earthquakes may lead to significant economic and social consequences. This work focuses on the fragility assessment of reinforced concrete multi-span continuous bridges, which is a widespread structural typology in Italy. The study aims to individuate fragilities relevant to both local and global mechanisms, considering bridge components such as piers, bearings and deck members, in order to highlight the most vulnerable ones compromising the whole structural response under the seismic action. A probabilistic framework is developed considering both the site-dependent seismic hazard and the most important Engineering Demand Parameters (EDPs) characterizing the structural response. The first one accounts for the record-to-record variability as well as the parameters governing the seismic scenario in which the structure is located, while the latter ones are individuated depending on the structural typology and the identified vulnerabilities. Multiple Stripe Analyses are performed with the aim of providing insights about the seismic response of the bridge class at hand and of furnishing the fragility curves for all the response parameters relevant for the structural system. Starting from a real case study located in Centre Italy, a couple of reinforced concrete bridge models is developed in order to consider the influence of different heights for the piers and to provide a forecast for the structural behaviour of the selected bridge class. The models are able to capture the failure mechanisms most likely to occur. Performance thresholds are chosen for each bridge component considering the relevant limit state demands according to the current codes and literature. As a result, fragility curves provide useful insights about the main structural deficiencies of the system at hand
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
A probabilistic study on impedances and kinematic response factors of square pile groups in homogeneous soils
Full text linkThe complexity of the Soil-Structure Interaction (SSI) problem is mainly due to difficulties related to the modelling of the soil-foundation behaviour, which is not only frequency-dependent, but is also largely influenced by uncertainties related to soil properties and stratigraphic conditions. According to a sub-structuring scheme for the analysis of SSI problems, a deterministic approach is usually adopted for the analysis of the soil-foundation system assuming properties and geotechnical models based on the expert judgment, despite the fact that uncertainties related to the intrinsic variability of soil parameters are widely recognised and confirmed by experimental campaigns and laboratory tests.
This paper presents a probabilistic study on the dynamic behaviour of square pile group foundations in homogeneous soils, focusing on the effects of the uncertainties related to (i) the frequency-dependent impedance functions and (ii) the kinematic response factors. Above quantities are required to define compliant restraints for the modelling of the soil-foundation system in performing inertial soil-structure interaction analysis, and for the definition of the foundation input motion starting from the free-field motion. Square pile groups are considered, and uncertainties are described through probabilistic distributions of parameters governing the soil-foundation dynamic response. The probabilistic analyses are performed through a numerical model developed by the Authors and some results are presented to show and discuss the variability of the results. In addition, a sensitivity analysis is performed to assess the influence of each variable uncertainty on the system response. Overall, response quantities are found to be very sensitive to shear wave velocity, although soil density and pile elastic modulus may often play a significant role
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
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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