1,720,999 research outputs found
Value of information of static and modal data for a concrete bridge exposed to reinforcement corrosion
No full textMeasurements performed on ageing bridges can provide information on the remaining capacity of these structures. Nevertheless, these measurements come at a cost, whereas the budgets for maintenance are limited. Based on pre-posterior analyses, the Value of Information (VoI) of these measurements can be determined on beforehand and the most optimal measuring strategy can be chosen. However, applying these VoI analyses to real-world structures, considering the time-dependent and spatial character of degradation, can be challenging. In this work, a case study is considered where the VoI analysis is applied to a reinforced concrete girder bridge subjected to corrosion, considering two situations: one with corrosion due to carbonation and one with corrosion due to chlorides. The influence of different assumptions in the VoI analysis is investigated
Probabilistic assessment of the moment-curvature response of PC beams with different corrosion scenarios
No full textCorrosion of the reinforcement significantly affects the resistance and ductility of concrete members. While various approaches have been proposed to study the sectional response of corroded reinforced concrete structures, the effects of corrosion on prestressed concrete (PC) members still poses significant challenges. Therefore, this study focuses on investigating the bending resistance of prestressed concrete sections with different corrosion scenarios through probabilistic assessment using Monte Carlo simulations based on preliminary results of previous work. First, the mechanical properties of the materials and the investigated pit depths have been established as input parameters of the cross-sectional model. To account for corrosion in the constitutive behaviour of the prestressing strands, the Simplified Model for Corroded Prestressing Strands (SCPS model) has been adopted. Furthermore, different statistical distributions of the pit depths are derived to represent different corrosion scenarios. Subsequently, Monte-Carlo simulations are utilized to capture the inherent randomness associated with the mechanical properties and pit depths in the sectional response of PC elements. Based on the outcome of these simulations, the influence of corrosion on the moment-curvature response as well as the expected failure mode are assessed. Finally, the latter results are investigated for different scenarios of corrosion, providing a comprehensive understanding of the effects of corrosion in PC elements and the associated uncertainties. These findings are relevant to researchers, engineers, and practitioners involved in the design, assessment, and maintenance of prestressed concrete structure
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
Partial safety factor for the design strength prediction of naturally corroded prestressing strands
No full textExisting reinforced and prestressed concrete structures are often affected by corrosion triggering high annual maintenance costs and impairing their safety, durability and serviceability. Although scientific studies have been devoted to the development of reliable methods for determining the residual resistance of such structures, the daily engineering practice is hindered by the lack of simplified models that consider all relevant uncertainties. The present contribution defines a partial factor for the calculation of the design tensile strength of corroded prestressing strands. To this aim, uncertainties related to material properties and geometry are defined according to the latest draft of the future fib Model Code 2020 prescriptions, whereas the model uncertainty is evaluated for a novel model, which derives the tensile strength based on the maximum penetration depth of the most corroded wire. First, the spatial variability of pitting corrosion of several naturally corroded prestressing strands is investigated by means of a 3D scanning technique. Second, a procedure for the estimation of the maximum penetration depth of a corroded prestressing strand is introduced. Finally, a simplified stressstrain relationship, named SCPS-model, is adopted for the prediction of the residual ultimate strength of prestressing strands. The obtained outcomes provide a useful tool for the assessment of existing prestressed concrete structures subjected to corrosion deterioration in everyday engineering practice
Probabilistic assessment of the moment-curvature response of PC beams subjected to corrosion.
No full textIn recent literature, several approaches have been proposed for the sectional response of corroded rein-forced concrete structures. However, the lack of knowledge on corroded prestressed concrete (PC) members is still present. The present work focuses on the probabilistic assessment of the sectional response of a PC member by considering the influence of chloride-induced corrosion. First, the proba-bility distributions of the mechanical properties and the maximum pit depth are established. Second, the SCPS-model is then adopted to derive the residual stress-strain relations of corroded strands. Third, the effect of the random nature of the mechanical properties is investigated via Monte-Carlo simula-tions. Finally, the main outcomes enable to: (i) quantify the expected failure mode in a probabilistic way, and (ii) assess the influence of the selected random variables on the moment-curvature response
Numerical assessment of the load-bearing capacity and reliability of existing bridges with dapped-end beams
No full textThe aim of this work is to evaluate the structural reliability of a corroded dapped-end beam belonging to an existing 70-year-old reinforced concrete bridge, by comparing the results obtained from a semi-probabilistic method with those provided by a fully probabilistic approach using Monte Carlo simula-tions. The resistance of the element was evaluated through a strut-and-tie model where corrosion was applied, considering both the initiation and propagation periods. The study highlights the potential of semi-probabilistic analyses while recognising the superior accuracy of full-probabilistic methods
- …
