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621.
GPS measurements were collected within the framework of the VLNDEF (Victoria Land Network for DEFormation control) project, which was started in 1999 with the aim of detecting crustal deformation in Northern Victoria Land (Antarctica). The network was established in 1999 and is composed of one permanent station (TNB1), which has been observing since 1998, and 28 periodically surveyed control points. Three complete campaigns and some partial surveying of the network have been carried out to date.Data processing and analysis have been performed using an undifferenced approach for the network position within the ITRF. A double-differences-based strategy has been applied for movement detection. The data processing and analysis of results have been carried out for all available data, both periodically acquired and long time series.GPS measurements collected between December 1999 and February 2006 indicate a mean “absolute” motion of the region of ve = 11.3 mm/yr and vn = − 11.1 mm/yr and rock uplift rates of vu = 2.8 mm/yr. These values are consistent with Antarctic plate motion and the general postglacial rebound models of the region. The relative motions within VLNDEF are small and only few points show velocities greater than the confidence levels. 相似文献
622.
Masoud Moghaddasi Gregory A. MacRae J. G. Chase Misko Cubrinovski Stefano Pampanin 《地震工程与结构动力学》2015,44(11):1805-1821
This paper introduces a simple method to consider the effects of inertial soil–structure interaction (SSI) on the seismic demands of a yielding single‐degree‐of‐freedom structure. This involves idealizing the yielding soil–structure system as an effective substitute oscillator having a modified period, damping ratio, and ductility. A parametric study is conducted to obtain the ratio between the displacement ductility demand of a flexible‐base system and that of the corresponding fixed‐base system. It is shown that while additional foundation damping can reduce the overall response, the effects of SSI may also increase the ductility demand of some structures, mostly being ductile and having large structural aspect ratio, up to 15%. Finally, a design procedure is provided for incorporation of the SSI effects on structural response. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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624.
Seismic Modal Contribution Factors 总被引:1,自引:0,他引:1
Michele Palermo Stefano Silvestri Giada Gasparini Tomaso Trombetti 《Bulletin of Earthquake Engineering》2015,13(10):2867-2891
625.
The study of two motion control-based seismic retrofit solutions for a low-rise reinforced concrete school building is presented in this paper. The building was assumed as a benchmark structure for a Research Project financed by the Italian Department of Civil Protection, and is representative of several similar public edifices designed with earlier Technical Standards editions, in Italy as well as in other earthquake-prone European countries. The two solutions refer to the alternative earthquake protection strategies based on the concepts of supplemental damping and seismic isolation, respectively. Namely, they consist in the installation of: (1) a dissipative bracing system incorporating pressurized fluid viscous spring-dampers; and (2) a base isolation system including double friction pendulum sliding bearings. The structural characteristics of the building, and a synthesis of the investigation campaigns developed on it, are initially presented. The mechanical parameters, dimensions, locations and installation details of the constituting elements of the two protective systems are then illustrated, along with the performance assessment analyses carried out in original and rehabilitated conditions according to a full non-linear dynamic approach. The results of the analyses show a remarkable enhancement of the seismic response capacities of the structure for both retrofit hypotheses. This allows reaching the mutual high performance levels postulated in the two rehabilitation designs with remarkably lower costs and architectural intrusion as compared to traditional rehabilitation interventions designed for the same objectives. 相似文献
626.
627.
V. Mariani M. Tanganelli S. Viti M. De Stefano 《Bulletin of Earthquake Engineering》2016,14(3):805-819
It is well known that the axial load plays an important role in the evaluation of the structural capacity of RC columns. In existing buildings this problem can be even more significant than in new ones, since the material can easily present poor mechanical properties. The paper is aimed at the investigation of the role of the axial load variation on the seismic performance of RC columns of a case-study, i.e. a doubly symmetric 4-storey RC building. The effects of the axial load variation have been checked on the first storey columns, by comparing the seismic response, measured in terms of chord rotation and shear force, with the corresponding capacity. The sensitivity of the seismic performance to the axial load is evaluated with special attention on the type of analysis adopted to determine the seismic response and on considering a wide range of values for the concrete strength. The study points out a non-negligible effect of the axial load variation on the seismic response of the case-study building, especially when combined to concrete strength variability. 相似文献
628.
Rajesh P. Dhakal Atefeh Pourali Ali Sahin Tasligedik Trevor Yeow Andrew Baird Gregory MacRae Stefano Pampanin Alessandro Palermo 《地震工程与工程振动(英文版)》2016,15(1):1-17
This paper summarizes the research on non-structural elements and building contents being conducted at University of Canterbury in New Zealand. Since the 2010-2011 series of Canterbury earthquakes, in which damage to non-structural components and contents contributed heavily to downtime and overall financial loss, attention to seismic performance and design of non-structural components and contents in buildings has increased exponentially in NZ. This has resulted in an increased allocation of resources to research leading to development of more resilient non-structural systems in buildings that would incur substantially less damage and cause little downtime during earthquakes. In the last few years, NZ researchers have made important developments in understanding and improving the seismic performance of secondary building elements such as partitions, facades, ceilings and contents. 相似文献
629.
630.
Francesco G. Carollo Costanza Di Stefano Vito Ferro Vincenzo Pampalone Francesco Sanzone 《地球表面变化过程与地形》2016,41(7):867-874
In order to measure soil loss in equipped plots the estimate of the weight of solid material intercepted at their lower end is required. At the experimental area of Sparacia, Sicily, the runoff produced by an erosive event is collected within storage tanks with a capacity of about 1 m3. In this paper, the use of a new sampler is proposed to measure easily the weight of solid material eroded from an experimental plot and collected into a storage tank. The sampler is a cylinder having a closing valve at the bottom. Two different series of runs were carried out both to test the reliability of the sampler and to establish a sampling procedure, respectively. An analysis of various sampling configurations usable in the field differentiated by the number and location of sampling verticals in the tank cross‐section was finally carried out. The results of the present investigation are that the concentration measurement by the sampler was more accurate than that obtained by other methods involving a collection tank, agitation and sampling of the suspension. This sampler is cheap and usable in combination with a quick field sampling procedure which is particularly advisable when the number of plots equipped at an experimental area is large. The sampler was tested using a clay soil contained within cylinders and a cubic tank, but it appeared also to be usable with coarser sediment than clay and in combination with tanks having a different shape. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献