The damped cable system for seismic protection of frame structures — Part I: General concepts,testing and modeling     

Stefano Sorace  Gloria Terenzi 《地震工程与结构动力学》2012,41(5):915-928

Research studies on the damped cable system (DCS) for seismic protection of frame structures are presented in this paper and the accompanying one. This technology includes prestressed steel cables linked to pressurized fluid viscous spring‐dampers fixed to the foundation at their lower ends, and to the top floor, or one of the upper floors, at their upper ends. The cables have sliding contacts with the floor slabs, to which they are joined by steel deviators. The general characteristics of the system, as well as of the constituting spring‐dampers and cables, are initially discussed. The results of a laboratory testing campaign developed on a DCS prototype are examined, and transferred into the formulation of the finite element model of the system, conceived to be easily generated by commercial structural analysis programs. A second dynamic experimental investigation follows, concerning a pilot installation of the system on a full‐scale mock‐up building. The benefits of the protective technology are evaluated in terms of maximum displacements and accelerations, as well as of equivalent viscous damping coefficient and MDOF transmissibility ratio. Further sections of the study, including a preliminary sizing criterion of DCS, additional numerical enquiries aimed at optimizing its geometrical layout, and the application to a real case study building, are offered in the companion paper. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Land subsidence along the Ionian coast of SE Sicily (Italy), detection and analysis via Small Baseline Subset (SBAS) multitemporal differential SAR interferometry     

Fabio Canova  Cristiano Tolomei  Stefano Salvi  Giovanni Toscani  Silvio Seno 《地球表面变化过程与地形》2012,37(3):273-286

The paper presents the results of a multi‐temporal, differential interferometric synthetic aperture radar (DInSAR) analysis aiming to identify active surface deformation phenomena in south‐eastern Sicily. The study area has been chosen because of its strong seismicity, high concentration of industrial and agricultural activities, and high density of people living in the coastal area. Furthermore, the morphology, lithology and climatic features of this sector of the Hyblean foreland are suitable for an interferometric analysis, providing a high coherence over the area. The Small BAseline Subset (SBAS) multitemporal DInSAR technique was used to calculate mean ground velocity maps and displacement time series from a large data set of European Remote Sensing Satellites (ERS 1–2) images spanning the time period 1992–2000. The reliability of the DInSAR results was tested calculating the East_SAR and Up_SAR values over two permanent global positioning system (GPS) stations in the area, and comparing them with the East_GPS and Up_GPS values. The residuals between GPS and DInSAR velocities were 1 and 0.6 mm/yr for the Up and East components, respectively. Four main subsiding areas, previously undetected, have been identified, corresponding with the towns of Augusta, Siracusa, Priolo, and Villasmundo. The observed deformation phenomena are located within coastal structural basins, filled with Pleistocene and Holocence deposits, except the Villasmundo land subsidence, which is located on the Hyblean plateau. The measured deformation rates reach values up to ?18 mm/yr in Augusta, –6 mm/yr in Siracusa, –5 mm/yr in Villasmundo and ?4.5 mm/yr in Priolo. The examination of velocity profiles, time series, and geological data allows us to relate all the detected deformation patterns primarily to groundwater over‐exploitation. A multi‐dimensional interpolation with kriging was performed to obtain a field subsidence map. A first‐order elastic deformation model was used to simulate the peculiar features of the Villasmundo subsidence. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Geodetic GPS-based analysis of recent crustal motions in Victoria Land (Antarctica)   总被引：1，自引：0，他引：1  

Antonio Zanutta  Luca Vittuari  Stefano Gandolfi   《Global and Planetary Change》2008,62(1-2):115-131

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 v_e = 11.3 mm/yr and v_n = − 11.1 mm/yr and rock uplift rates of v_u = 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   

Seismic design of yielding structures on flexible foundations          下载免费PDF全文

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   

Effects of the filtering action exerted by piles on the seismic response of RC frame buildings     

Luca de Sanctis  Raffaele Di Laora  Nicola Caterino  Giuseppe Maddaloni  Stefano Aversa  Alessandro Mandolini  Antonio Occhiuzzi 《Bulletin of Earthquake Engineering》2015,13(11):3259-3275

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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

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Motion control-based seismic retrofit solutions for a R/C school building designed with earlier Technical Standards     

Stefano Sorace  Gloria Terenzi 《Bulletin of Earthquake Engineering》2014,12(6):2723-2744

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   

Erratum to: Peak velocities estimation for a direct five-step design procedure of inter-storey viscous dampers     

Michele Palermo  Stefano Silvestri  Luca Landi  Giada Gasparini  Tomaso Trombetti 《Bulletin of Earthquake Engineering》2016,14(2):621-621

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Combined effects of axial load and concrete strength variation on the seismic performance of existing RC buildings     

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   

Seismic performance of non-structural components and contents in buildings: an overview of NZ research     

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