1,721,149 research outputs found
Developments Relating to Seismic Action in the Eurocode 8 of Next Generation
No full textThe purpose of this paper is to present the main changes introduced by CEN-TC250-SC8 concerning seismic action in the next revision of Eurocode 8, consisting principally of:- Introducing the concept of seismic action class in place of seismicity level.- Anchoring the standard spectrum by its plateau value, S-alpha, and its value at 1 s spectral period, S-beta, instead of the PGA.- Introducing, in an informative annex, two European hazard maps, one for S-alpha, and one for S-beta, both defined for 475 years return period, based on the ESHM20 hazard model.- Revising the site categorization by introducing the bed rock depth in addition to the shear wave velocity.- Introducing new site amplification factors based on this site categorisation and dependent on input motion level.- Introducing a new spatial model of input motion for bridges and pipelines.- Providing miscellaneous specifications on conventional values of magnitude and strong motion duration, dependence of spectra to damping, ..
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
Numerical modeling of the interaction of pressurized large diameter gas buried pipelines with normal fault ruptures
Full text linkProcedura automatica per il calcolo delle interferenze elettromagnetiche fra sistemi di diversa natura
No full textLa necessità di alimentare grandi agglomerati di utenze civili ed industriali comporta la coesistenza, sullo stesso territorio, di linee di trasmissione e distribuzione dell'energia elettrica, di sistemi di trazione ferrotranviaria, di reti di telecomunicazione e di strutture metalliche continue e ramificate come acquedotti e gasdotti. Tra questi diversi "sistemi di conduttori" spesso si presentano intersezioni e parallelismi che possono originare interferenze elettromagnetiche con conseguenti azioni di reciproco disturbo e/o aspetti riguardanti la sicurezza. Questo tipo di problemi si sono particolarmente acuiti, da una parte con l'estendersi delle reti elettriche e con l’aumento delle correnti di guasto, dall'altra con la diffusione sempre più spinta di apparecchiature elettroniche ad elevata suscettibilità elettromagnetica. Sempre più spesso quindi, nella tecnica impiantistica, ci si trova nella necessità di affrontare, sia a livello di predeterminazione che di verifica, il calcolo delle grandezze elettriche in gioco nelle interferenze di sistemi complessi. A questo fine è stata sviluppata una procedura, facilmente implementabile su normali Personal Computer tramite programmi di calcolo matematico di tipo commerciale. Questa consente, con gli usuali metodi dell’analisi circuitale in regime sinusoidale, la determinazione accurata delle tensioni nei vari punti del sistema e la ripartizione delle correnti nei relativi conduttori
Seismic displacement based design of structures: relevance of soil structure interaction.
No full textIn this paper a brief summary of the seismic design method known as “direct displacement – based design” (DDBD) is presented, with some discussion of the appropriate seismic design input to be used, on the applicability to retaining structures and on the relevance of including nonlinear soil-structure interaction in the DDBD and the tools to account for it, with reference to shallow foundations
Application of neural networks and statistical pattern recognition algorithms to earthquake risk evaluation
No full textThis paper reports the experimental results on the application of different pattern recognition algorithms to the evaluation of earthquake risk for real geological structures. The study area used for the experiments is related to a well-known geological structure representing a "triangular valley over bedrock". Performances obtained by two neural networks and two statistical classifiers are reported and compared. The advantages provided by the use of methods for combining multiple classifiers are also discussed and the related results reported. (C) 1997 Elsevier Science B.V
The older the better? The strange case of empirical ground motion models in the near-source of moderate-to-large magnitude earthquakes
Full text linkThis paper aims at providing a quantitative evaluation of the performance of a set of empirical ground motion models (GMMs), by testing them in a magnitude and distance range (Mw = 5.5 ÷ 7.0 and Joyner-Boore source-to-site distance Rjb ≤ 20 km) which dominates hazard in the highest seismicity areas of Italy for the return periods of upmost interest for seismic design. To this end, we made use of the very recent release of the NESS2.0 dataset (Sgobba et al. NESS2.0: an updated version of the worldwide dataset for calibrating and adjusting ground motion models in near-source. Istituto Nazionale di Geofisica e Vulcanologia (INGV), 2021. https://doi.org/10.13127/NESS.2.0), that collects worldwide near-source strong motion records with detailed metadata. After selection of an ample set of GMMs, based on either their application in past seismic hazard assessment (SHA) studies or for their recent introduction, a quantification of between- and within-event residuals of predictions with respect to records was performed, with the final aim of shedding light on the performance of existing GMMs in the near-source of moderate-to-large earthquakes, also in view of their potential improvement by taking advantage of results from 3D physics-based numerical simulations
Foreword to the Special Issue on the ITACA Strong Motion Database
No full textThe Special Issue of the Bulletin of Earthquake Engineering devoted to the new Italian strong motion database ITACA (ITalian ACelerometric Archive) is introduced in this foreword. An overview of the papers published in this issue is presented, providing an idea of the number of problems encountered in the compilation of a database as rich of information as ITACA, of the solutions adopted and of the possible research and practical applications. Most of the contents, though specifically addressed to ITACA and to its accelerograms, can be usefully thought of as an exemplification of approaches and methods that can be used for, and extended to, similar databases in other countries
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
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