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41.
An index is proposed for the quantitative evaluation of topographical effects, as may be required in seismic microzoning and structural design applications. This topographical effects index (TEI) is defined as the relative Arias intensity for a given position. As an example, the TEI is calculated for a semicircular canyon excited by an earthquake signal that consists of plane elastic SH waves and is characterized by a theoretical spectrum of accelerations. The analytical solution by Trifunac15 provides the transfer functions for this problem. The behaviour and spacial distribution of the calculated TEI values are illustrated for different incidence angles and spectral parameters. The proposed index appears useful for generating quantitative criteria which, after proper confirmation by instrumental recordings, could be considered in earthquake code provisions. 相似文献
42.
Dr. Ignazio Dagnino 《Pure and Applied Geophysics》1952,21(1):43-48
Riassunto Per 52 località del Bacino del Mediterraneo ed adiacenze sono state calcolate le prime tre componenti armoniche dell'andamento annuo della pressione atmosferica in base alle rispettive medie mensili. La distribuzione dei valori della prima armonica permette di dedurre che dal punto di vista climatico il Bacino del Mediterraneo può venir distinto in cinque parti, aventi ciascuna caratteristiche diverse nei confronti dell'andamento considerato.
Summary The first three harmonic components of the annual variation of the atmospheric pressure have been calculated on the basis of their respective monthly averages for 52 localities on the basin of the Mediterranean and adjoining regions. The repartition of the values of the first harmonic component allows the deduction that from the climatic point of view, the basin of the Mediterranean can be divided into five parts, each one having different characteristics compared to the movement under consideration.相似文献
43.
Dr. Ignazio Dagnino 《Pure and Applied Geophysics》1948,12(3-4):162-167
Riassunto L'A. riferisce sulla livellazione di precisione da lui eseguita per determinare le quote assolute dei caposaldi esterni ed
interni dell'Istituto Geofisico e Geodetico dell'Università di Genova, con collegamento allo zero mareografico locale.
Zusammenfassung Der Verf. berichtet über das von ihm durchgeführte Feinnivellement um die vertikale Lage einiger Festpunkten des Geophysikalisch-Geod?tischen Instituts der Universit?t Genua genau zu bestimmen und zwar mit Verbindung an die dortige mareographische Station.相似文献
44.
Lili Cafarella Stefano Urbini Cesidio Bianchi Achille Zirizzotti Ignazio E. Tabacco Alessandro Forieri 《Polar research》2006,25(1):69-73
Radio echo sounding (RES) measurements were collected from 1995 to 2003 during Italian Antarctic expeditions over the Vostok-Dome C region. The data collected allow for the reconstruction of a bedrock elevation map between the Belgica Highlands and the Aurora Subglacial Basin (112.0ø - 124.0ø E; 74.0ø - 78.0ø S). Moreover, analysis of the RES data has revealed one of the thickest ice covers in Antarctica (4755 Ø 16 m; 118.321ø E, 76.059ø S) as well as five new subglacial lakes. 相似文献
45.
Alessandra Marini Ezio Giuriani Andrea Belleri Stefania Cominelli 《Bulletin of Earthquake Engineering》2018,16(9):4001-4025
In the seismic retrofit of existing masonry constructions, global interventions are often needed to inhibit the onset of local mechanisms and to engage the whole building box-like structural behaviour. Such interventions are represented by perimeter ties and roof and floor diaphragms. This paper considers the roof diaphragm strengthening solution and investigates the use of stud connections securing the roof thin-folded shell to the perimeter walls. Stud connections serve the dual purpose of collecting and transferring the out-of-plane inertia forces of the masonry walls to the roof diaphragm, as well as transferring the diaphragm reaction forces to the shear walls. Specific detailing of the stud connection and the adoption of an improved lime-mortar overlay on the top of the masonry walls are proposed to improve the connection strength; without such improvements, the connection capacity would be jeopardised by the reduced shear resistance of the masonry wall due to the absence of significant vertical confining action at the roof level. The intervention entirely changes the behaviour of the connection and significantly reduces shear stresses on the masonry wall. The structural behaviour of the connection is analysed and discussed. Emphasis is made on the conceptual design of laboratory and in-field test procedures and testing frames in order to replicate the boundary conditions in real applications. In-situ tests may help during the design of the roof thin-folded shell system and allow for the efficiency assessment of the connections prior to the final intervention, thereby proving the actual feasibility of the retrofit solution. 相似文献
46.
Paolo Augliera Ezio D’Alema Simone Marzorati Marco Massa 《Bulletin of Earthquake Engineering》2010,8(5):1091-1104
The necessity of a dense network in Northern Italy started from the lack of available data after the occurrence of the 24th
November 2004, Ml 5.2, Salò earthquake. Since 2006, many efforts have been made by the INGV (Italian National Institute for Geophysic and Vulcanology), Department of Milano-Pavia (hereinafter INGV MI-PV), to improve the strong-motion monitoring of the Northern Italy regions.
This activity led to the installation of a strong-motion network composed by 20 accelerometers, 4 coupled with 20-bits Lennartz
Mars88 recorders, 12 coupled with 24-bits Reftek 130 recorders and 4 coupled with 24-bits Gaia2 recorders. The network allow
us to reduce, in the area under study, the average inter-distances between strong-motion stations from about 40 km (at November
2004) to 15 km. At present the network includes nine 6-channels stations where velocity sensors work together the strong-motion
ones. The data transmission is assured by modem-gsm, with the exception of four stations that send data in real time through
a TCP/IP protocol. In order to evaluate different site responses, the stations have been installed both in free field and
near (or inside) public buildings, located in the center of small villages. From June 2006 to December 2008 a dataset of 94
events with local magnitude range from 0.7 to 5.1 has been collected. An ad hoc data-processing system have been created in
order to provide, after each recorded event, engineering parameters such as peak ground acceleration (PGA) and velocity (PGV),
response spectra (SA and PSV), Arias and Housner intensities. Data dissemination is achieved through the web site , while the waveforms are distributed through the Italian strong motion database (). 相似文献
47.
3D Response analysis of an instrumented hill at Matsuzaki, Japan, by a spectral method 总被引:2,自引:0,他引:2
Strong ground motion observed at an instrumented hill site is first analysed through the standard (SSR) and the horizontal-to-vertical (HVSR) spectral ratio techniques. A reasonable agreement is found between these approaches. The observations are then compared with 3D numerical simulations, performed with a highly efficient numerical code based on a spectral method, that allowed for reasonable computer times also on a PC. The observed amplification is significantly higher than that computed with a 3D homogeneous model of the mountain, suggesting that local response is governed by large-scale and small-scale soil heterogeneities rather than by topographic site effects. The introduction of a local near-surface inclusion of nonhomogeneous soil material under one of the recording stations has not significantly improved the numerical results. The observed data are also compared with the results of simplified simulations, either using 2D homogeneous models or coupling the 3D response with a 1D local soil profile. The results of such simplified approaches are discussed and their usefulness is emphasised. 相似文献
48.
Toward a ground-motion logic tree for probabilistic seismic hazard assessment in Europe 总被引:9,自引:2,他引:7
Elise Delavaud Fabrice Cotton Sinan Akkar Frank Scherbaum Laurentiu Danciu Céline Beauval Stéphane Drouet John Douglas Roberto Basili M. Abdullah Sandikkaya Margaret Segou Ezio Faccioli Nikos Theodoulidis 《Journal of Seismology》2012,16(3):451-473
The Seismic Hazard Harmonization in Europe (SHARE) project, which began in June 2009, aims at establishing new standards for probabilistic seismic hazard assessment in the Euro-Mediterranean region. In this context, a logic tree for ground-motion prediction in Europe has been constructed. Ground-motion prediction equations (GMPEs) and weights have been determined so that the logic tree captures epistemic uncertainty in ground-motion prediction for six different tectonic regimes in Europe. Here we present the strategy that we adopted to build such a logic tree. This strategy has the particularity of combining two complementary and independent approaches: expert judgment and data testing. A set of six experts was asked to weight pre-selected GMPEs while the ability of these GMPEs to predict available data was evaluated with the method of Scherbaum et al. (Bull Seismol Soc Am 99:3234?C3247, 2009). Results of both approaches were taken into account to commonly select the smallest set of GMPEs to capture the uncertainty in ground-motion prediction in Europe. For stable continental regions, two models, both from eastern North America, have been selected for shields, and three GMPEs from active shallow crustal regions have been added for continental crust. For subduction zones, four models, all non-European, have been chosen. Finally, for active shallow crustal regions, we selected four models, each of them from a different host region but only two of them were kept for long periods. In most cases, a common agreement has been also reached for the weights. In case of divergence, a sensitivity analysis of the weights on the seismic hazard has been conducted, showing that once the GMPEs have been selected, the associated set of weights has a smaller influence on the hazard. 相似文献
49.
50.
Ignazio Maria Viola 《Ocean Engineering》2009,36(12-13):974-984
A computational fluid dynamics (CFD) code was applied to an America's Cup Class Yacht to investigate sailing performance in a downwind configuration. Apparent wind angles at 45°, 105° and 120° are reported, sailed with mainsail and asymmetrical spinnakers. Numerical results are in good agreement with wind tunnel data. A large mesh investigation was performed, ranging from 60,000 elements up to 37 million elements, which shows a converging trend to the experimental values with differences smaller than 3% in both lift and drag. The most commonly used turbulence models in sail applications were tested and the results are presented here in two meshes with 1 million elements and 6.5 millions, respectively. All turbulence models over-estimate forces more than solving the Navier–Stokes system without any additional equations, hence turbulence models do not increase solution accuracy according to these results. 相似文献