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Fabio Mazza 《地震工程与结构动力学》2019,48(4):432-453
The out-of-plane (OOP) behaviour of masonry infills (MIs), inserted in reinforced concrete (r.c.)–framed buildings, is recognized as one of the most important failure modes of this nonstructural element during an earthquake, which may be a consequence of simultaneous or prior in-plane (IP) damage. A five-element macro-model, with four diagonal OOP non-linear beams and one horizontal IP non-linear truss, with an equivalent mass of the infill panel divided between two central nodes, takes into account the IP and OOP failure modes occurring in the event of seismic loading. Pivot hysteretic models predict the non-linear IP and OOP force-displacement laws of the infill panel, based on geometrical rules defining loading and unloading branches. Firstly, a calibration of the proposed IP-OOP interaction model of MIs is carried out considering full-scale experimental results of traditional masonry typologies. Each specimen is initially subjected to in-plane quasi-static cyclic loading, until a maximum drift is reached, and then one-sided OOP cycles are imposed pushing in the horizontal direction and back to zero force. Then a numerical investigation considers masonry infills of an existing six-storey r.c.-framed building designed in compliance with a former Italian seismic code. To evaluate the interaction, the results of simultaneous IP and OOP cyclic tests on MIs at the top, intermediate, and lowest levels of the test structure are presented, assuming different displacement histories: (1) OOP loading faster than IP, at the sixth storey; (2) equal IP and OOP loading, at the third storey; (3) IP loading faster than OOP, at the first storey. Finally, attention is focused on the contribution of masonry infills to the IP and OOP energy dissipation of r.c.-framed structures. 相似文献
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The study of magnetization of the ceramic material from 21 archeological monuments of Portugal (the Evora province), dated archeologically from the Bronze Age to the end of the Iron Age has been carried out. For the purpose of more detailed timing of the material from the monuments the method of ceramic age dating on the basis of its porosity has been used. In order to take into account the distorted factors in the determination of the parameters of the ancient geomagnetic field with the aim of the maximal approximation to the actual values the diagnostic features of magnetite weathering have been considered and the level of weathering of the magnetic fraction in the ceramics from archeological monuments has been determined. The data of geomagnetic field-strength variation in the time interval of the 12th century BC to the beginning of the Common Era have been obtained. The field-strength at this time interval varied in the range of 60–90 micro Tesla with the maximal values in the 9th, 8th, and the second half of the 5th to the beginning of the 4th century BC. In addition, the timing of the ceramic material from the urns of the megalithic complex Monte de Tera of the Evora province has been clarified. 相似文献
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V. V. Shcherbakova G. V. Zhidkov V. P. Shcherbakov 《Izvestiya Physics of the Solid Earth》2008,44(10):816-821
A large volume of data on the paleointensity H an obtained by A.S. Bol’shakov and G.M. Solodovnikov is ignored in modern reconstructions because the authors did not indicate whether they used the check-point procedure for the detection of chemical alterations in rocks associated with determination of H an. The paper presents new values of H an determined by the Thellier-Coe method with the use of the checkpoint procedure from samples of the Armenian collection of Cretaceous rocks used in published studies of Bol’shakov and Solodovnikov. The new results are close to the published ones and point to a small value of the geomagnetic field in the Cretaceous, thereby corroborating Bol’shakov-Solodovnikov’s hypothesis on a low paleofield in the Mesozoic. Our study of samples of the collection studied confirms the reliability of Bol’shakov-Solodovnikov’s determinations of H an. 相似文献
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An earthquake is regarded as a fracture from the viewpoint of continuum mechanics, in which stress and strain play key roles in understanding the nature of a seismic source. This review briefly outlines the mechanics of a seismic source in terms of the dislocation model and crack model. The introduction includes the Coulomb failure criterion, static stress drop, dynamic stress drop, the Griffith criterion, and the scaling of source parameters. The selection of topics in the introduction emphasizes the application of seismic data, i.e., in practice, the mechanical parameters introduced here are measurable in the interpretation and analysis of seismic waveform data. 相似文献
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《国际泥沙研究》2002,(4)
I. Soil erosion and sediment yield Upland Erosion Modeling with CASC2D-SED Pierre JULIEN and Rosal韆 ROJAS (No. 4, pp. 265-274) Effects of Soil Crusting on Soil Moisture, Runoff and Erosion: Field Observations Tongxin ZHU (No. 4, pp. 298-303) II. Environmental and ecological sedimentation Numerical Study on Environmental Impacts of the Third Shanghai Sewerage Project Cheng LIU, Huiran WANG, Y… 相似文献
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《国际泥沙研究》2001,16(4)
I. Soil erosion and sediment yieldDevelopment of Soil Erosion Index Model in Taiwan WatershedsVol. 16, No. 1, pp. 80-90 Modeling of Sediment Yield and Nonpoint Source Pollutant YieldVol. 16, No. 3, pp. 416-420 Runoff Generation Characteristics in Typical Erosion Regions on the Loess PlateauVol. 16, No. 4, pp. 473-485II. Environmental and ecological sedimentationLong Term Effects of Rehabilitation Measures on Bed Load Transport at the Salzach River Vol. 16, No. 2, pp. 95-102 Th… 相似文献
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《国际泥沙研究》2004,(4)
1. Soil erosion and sediment yieldAssessment of Soil Loss on Uncultivated Slope Land by Using 137Cs Techniquein the Upper Yangtze River Basin of China Mingyi FENG, Xinbao ZHANG, Anbang WEN and Xiubin HE (No. 1, pp. 60-65)Evaluation of Erosion Productivity Impact Calculator (EDIC) Model forMIDDLE Mountain Region of Nepal Sohan Kumar GHIMRE and Mukand Singh BABEL (No. 2, pp. 106-122)Rill Ero… 相似文献
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《国际泥沙研究》2005,20(4):366-367
I. Soil Erosion and Sediment Yield Downslope Erosion Process under Upslope Runoff and Sediment Using a Dual-Box System Peiqing Xiao, Fenli Zheng and Wenyi Yao (No. 2, pp. 136-142) Modeling Ephemeral Gully Erosion for Conservation Planning George R. FOSTER (No. 3, pp. 157-175) Hydrologically Driven Mechanisms of Headcut Development M. J. M. R?MKENS and S. N. PRASAD (No. 3, pp. 176-184) Numerical Simulation of Head-cut with a Two-layered Bed Yafei JIA, Tadanori KITAM… 相似文献
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The statistical mechanics of earthquakes adopts the concepts and methodology of statistical mechanics, especially the theory of critical phenomena, in studying the preparation, initiation, propagation and healing of earthquake rupture, which forms a new branch in the physics of seismic source in recent years. This article introduces to the fundamental concepts of the statistical mechanics of earthquakes. The introduction includes the seismic Hamiltonian, percolation model, earthquake rupture nucleation, and Burridge-Knopoff spring-block model. It is pointed out that some of the statistical mechanical models of earthquakes have a sound seismological basis. There is a smooth "transition" from the "classical" theory to the "modern" theory of seismic source. 相似文献
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NUCTECH is a worldwide leading company specialized in research & development of x-ray inspection technology, as well as system design, manufacture, engineering and customer service. With the radiation imaging technology as its core competence, NUCTECH founded in July 1997, is a prestigious high-tech company originated from Tsinghua University. NUCTECH has developed and produced the THSCANTM Container/Vehicle Inspection Systems with linear accelerators, the Air Cargo/Vehicle Sec… 相似文献
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Reconstruction of the Production Rate of Cosmogenic 14C in the Earth’s Atmosphere for 17 000–5000 BC
Kudryavtsev I. V. Volobuev D. M. Dergachev V. A. Nagovitsyn Yu. A. Ogurtsov M. G. 《Geomagnetism and Aeronomy》2018,58(7):925-929
Geomagnetism and Aeronomy - Carbon isotope 14С is produced in the Earth’s atmosphere by energetic cosmic-ray (CR) particles. The data on its atmospheric abundance are used to... 相似文献
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Water Resources - The article considers an estimate of the effect of positive feedback in the mechanism of level oscillations in the Caspian Sea on the long-term level regime. The study was based... 相似文献
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L. I. Abalkin 《Water Resources》2006,33(6):713-714