This study focuses on the characterization of low-velocity (lower than 100 km/h) rockfall impact loads transferring to a thick steel-reinforced concrete (SRC) slab through a protective sand layer. A ...full-scale experimental tests campaign was performed, each test consisting in releasing a concrete block which, after a vertical free-fall, impacts a sand protective layer placed over a SRC slab, in order to represent an isolated rockfall impact to which an actual SRC structure could be exposed. During the impact, the vertical pressure distribution was observed using several pressure cells installed at the sand-slab interface. A total of 35 tests were carried out, systematically combining sand layer thickness (D), block's equivalent diameter (B), and free-fall drop height (H), related to impact velocity. The masses of the released blocks were in the range of 117 to 7399 kg, corresponding to diameters in the range of 0.42 to 1.79 m. Five free-fall drop heights, up to 33 m, were considered, to reach impact velocities up to 90 km/h, covering the range of most velocities observed in actual rockfall studies. Three thicknesses of the sand layer protecting the thick SRC slab were considered: 1, 1.5 or 2 m. Data reduction from this full-scale impact tests program makes it possible to characterize, for a given thickness of protective sand layer, the time-space pressure pulse distribution applied to the protected structure during the impact for a large range of rock boulder masses and speeds actually observed in the field.
Forum papers are thought-provoking opinion pieces or essays founded in fact, sometimes containing speculation, on a civil engineering topic of general interest and relevance to the readership of the ...journal. The views expressed in this Forum article do not necessarily reflect the views of ASCE or the Editorial Board of the journal.
This volume brings together state-of-the-art research on the development of infrastructure management, assessment, and rehabilitation techniques. It sheds light on pioneering work on innovative ...3D-printed concrete, novel methods for assessment of bridge decks, and advanced computer vision-based maintenance of civil infrastructure. The book is essential reading for infrastructure owners, engineers, and contractors, allowing them to gain insights into groundbreaking research that is paving the way toward sustainable and resilient infrastructure.
Selected peer-reviewed full text papers from the 21st Conference on the Rehabilitation and Reconstruction of Buildings (CRRB)Selected, peer-reviewed papers from the 21st Conference on the ...Rehabilitation and Reconstruction of Buildings (CRRB), November 28-29, 2019, Prague, Czech Republic.
Abstract To determine the water vapour permeability of porous building materials, the wet cup and dry cup tests are frequently performed. Those tests have shown to present high discrepancy. The water ...vapour permeability of building materials is an essential parameter to determine the hygrothermal behaviour of the material and its impact on indoor comfort. Several previous studies have aimed to improve the reproducibility of the tests, by improving the protocol, the analysis of the results, notably by taking into account the surface film resistance. Yet, it is commonly accepted with no evidence that this surface film resistance can be neglected for an air velocity above 2 m/s over the cup. This study aims at experimentally testing the influence of either the flow regime or the flow velocity on the robustness of the measured water vapour permeability. For this purpose, two mini wind tunnels were designed to produce a laminar or a turbulent flow above the cups with variable air velocity. Water vapour permeability tests were performed in the tunnels with varying air velocity and flow regime on earth plasters with different compositions. The results have shown that regardless of the air velocity and flow regime, the surface film resistance should not be neglected. Based on the presented results, to reach an optimal repeatability, the use of wind tunnels should be considered as they allow to precisely control the air flow above the samples.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
RationaleEngineered nanomaterials (ENMs) induce groundbreaking impacts by endowing unique properties to materials. However, uncertainties remain on their biological aftereffects. Entrusted by health ...and labour ministries, the French Public Health Institute launched since 2014 the EpiNano epidemiological surveillance program of workers potentially exposed to ENMs. The 2016–2020 national occupational health (OH) action plan inscribed the ENMs topic as of priority, with an enlargement to the construction and civil-engineering (CCE) sector. A scientific consortium was therefore established in order elaborate a standardised methodology to identify ENMs-exposed CCE workers.MethodsA comprehensive, structured PubMed review and web-search of technical documents was undertaken, complemented by in-depth experts’ interviews to collect contextual information regarding CCE nanoproducts.ResultsSeveral methodological challenges were primarily revealed, pertaining primarily to : (i) Demarcating the target population: Involvement of a large number of companies (400,000) of all sizes and activities; Massive delegation to subcontractors; Heterogeneity of socioprofessional categories (from engineers to operators) and occupations (around 22); (ii) Unknown exposures’ circumstances: no CCE nanoproducts inventories neither detailed composition information; Unawareness of CCE actors of nanoproducts’ use; Heterogeneity of ENMs incorporated in various matrices (cement, coatings, paints…) with unknown ENM release/exposure potential; Potentially passive occupational exposures; Myriad of confusion factors with interactions with other risks at workplace; (iii) Capturing and following the eligible population: a complex topic to be addressed with a lot of pedagogy for adhering workers; epidemiological follow-up hampered by high turnovers, duration of construction sites and language barrier. Discussions are ongoing to overcome these methodological challenges. As a first step, an awareness campaign and the establishment of CCE nanoproducts’ inventory will be launched soon.ConclusionsAn increase in CCE nanoproducts’ use is expected in the context of sustainable development and energy saving. This underscores the urgency to implement a specific surveillance system, by circumventing designing complexity.
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BFBNIB, CMK, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
•We present a methodology based on Factor Analysis and MDS for literature reviews.•We introduce the notion of research factor related to the presented methodology.•We summarize the state of the art ...about RE through 5 research factors.•We suggest future multi-disciplinary research directions for RE.
This paper offers an extensive literature review on the field of Resilience Engineering (RE), encompassing 472 contributions, including journal articles, conference proceedings and book chapters. Adopting the numbers of co-citations as a metric of conceptual proximity, this paper details the application of Factor Analysis and Multi-Dimensional Scaling, as groundbreaking means to extract relevant research factors. A temporal analysis in a multi-variate two-dimensional space confirms the significance and relevance of the identified research factors. An in-depth analysis of the five research factors, labeled as the need of RE, RE for modelling, defining and exploring RE, reflecting on RE, RE and improvisation, guides the definition of future research paths and open research questions within the field and across several domains, suggesting the need for multi-disciplinary future studies.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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