平面不规则基础隔震结构抗扭设计研究   总被引：1，自引：0，他引：1       下载免费PDF全文

黄小宁  王威  王宁  杜永峰 《地震工程学报》2020,42(5):1283-1288

针对平面不规则结构在水平地震作用下的振动特性，通过调整隔震层隔震支座的布置，得到3种不同工况的隔震层刚心与上部结构质心、刚心相对位置关系，分别以楼层位移和层间位移为指标的扭转位移比，作为平面不规则基础隔震结构扭转响应指标，利用弹塑性时程分析方法，通过对3种不同工况的扭转指标对比分析研究，提出适用于平面不规则基础隔震结构的抗扭设计方法。结果表明：对于平面不规则结构，应在保证隔震层扭转位移比小于1.2的基础上，使隔震层的刚心和上部结构的刚心分别位于上部结构质心的两侧，可有效控制上部结构的扭转。  相似文献   

Cryosphere evapotranspiration in the Tibetan Plateau: A review     

KunXin Wang  YinSheng Zhang  Ning Ma  YanHong Guo  YaoHui Qiang 《寒旱区科学》2020,12(6):355-370

Land surface actual evapotranspiration is an important process that influences the Earth's energy and water cycles and determines the water and heat transfer in the soil-vegetation-atmosphere system. Meanwhile, the cryosphere's hydrological process is receiving extensive attention, and its water problem needs to be understood from multiple perspectives. As the main part of the Chinese cryosphere, the Tibetan Plateau faces significant climate and environmental change. There are active interaction and pronounced feedback between the environment and ET_a in the cryosphere. This article mainly focuses on the research progress of ET_a in the Tibetan Plateau. It first reviews the ET_a process, characteristics, and impact factors of typical underlying surfaces in the Tibetan Plateau (alpine meadows, alpine steppes, alpine wetlands, alpine forests, lakes). Then it compares the temporal and spatial variations of ET_a at different scales. In addition, considering the current greening of cryosphere vegetation due to climate change, it discusses the relationship between vegetation greening and transpiration to help clarify how vegetation activities are related to the regional water cycle and surface energy budget.  相似文献   

Structure-specific selection of earthquake ground motions for the reliable design and assessment of structures   总被引：1，自引：1，他引：0  

E. I. Katsanos  A. G. Sextos 《Bulletin of Earthquake Engineering》2018,16(2):583-611

A decision support process is presented to accommodate selecting and scaling of earthquake motions as required for the time domain analysis of structures. Code-compatible suites of seismic motions are provided being, at the same time, prequalified through a multi-criterion approach to induce response parameters with reduced variability. The latter is imperative to increase the reliability of the average response values, normally required for the code-prescribed design verification of structures. Structural attributes like the dynamic characteristics as well as criteria related to variability of seismic motions and their compliance with a target spectrum are quantified through a newly introduced index, δ _sv–sc , which aims to prioritize motions suites for response history analysis. To demonstrate the applicability of the procedure presented, the structural model of a multi-story building was subjected to numerous suites of motions that were highly ranked according to both the proposed approach (δ _sv–sc ) and the conventional one (δ _conv ), that is commonly used for earthquake records selection and scaling. The findings from numerous linear response history analyses reveal the superiority of the proposed multi-criterion approach, as it extensively reduces the intra-suite structural response variability and consequently, increases the reliability of the design values. The relation between the target reliability in assessing structural response and the size of the suite of motions selected was also investigated, further demonstrating the efficiency of the proposed selection procedure to achieve higher response reliability levels with smaller samples of ground motion.  相似文献   

The 2014 Earthquake Model of the Middle East: seismogenic sources     

Laurentiu Danciu  Karin Şeşetyan  Mine Demircioglu  Levent Gülen  Mehdi Zare  Roberto Basili  Ata Elias  Shota Adamia  Nino Tsereteli  Hilal Yalçın  Murat Utkucu  Muhammad Asif Khan  Mohammad Sayab  Khaled Hessami  Andrea N. Rovida  Massimiliano Stucchi  Jean-Pierre Burg  Arkady Karakhanian  Hektor Babayan  Mher Avanesyan  Tahir Mammadli  Mahmood Al-Qaryouti  Doğan Kalafat  Otar Varazanashvili  Mustafa Erdik  Domenico Giardini 《Bulletin of Earthquake Engineering》2018,16(8):3465-3496

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Quantification of the amplitude variability of the ground motion in Argostoli,Greece. Variability of linear and non-linear structural response of a single degree of freedom system.     

E. Koufoudi  C. Cornou  S. Grange  F. Dufour  A. Imtiaz 《Bulletin of Earthquake Engineering》2018,16(9):3675-3685

The term “spatial variability of seismic ground motions” denotes the differences in the amplitude and phase content of seismic motions. The effect of such spatial variability on the structural response is still an open issue. In-situ experiments may be helpful in order to answer the questions regarding both the quantification of the spatial variability of the ground motion within the dimensions of a structure as well as the effect on its dynamic response. The goal of the present study is to quantify the variability of the seismic ground motion accelerations in the shallow sedimentary basin of Argostoli, Greece, and thereafter to identify its effect on the linear and non-linear elasto-plastic response of a single degree of freedom system in terms of spectral displacements. Around 400 earthquakes are used, recorded by the 21-element very dense seismological array deployed in Argostoli with inter-station spacing ranging from 5 to 160 meters. The seismic motion variability, evaluated in terms of spectral accelerations, is found to be significant and to increase with inter-station distance and frequency. Thereafter, the amplitude variability in terms of spectral displacements, which is indeed the linear response of a single degree of freedom (SDOF) system with various fundamental periods, is compared with the amplitude variability of a SDOF with non-linear elasto-plastic response. The variability of the maximum top displacement of the linear single degree of freedom system is estimated to be on average 12% with larger variabilities to be observed within two narrow frequency ranges (between 1.5 and 1.7 Hz and between 3 and 4 Hz). Such high variabilities are caused by locally edge-generated diffracted surface waves. The non-linear perfectly elasto-platic structural response of the SDOF system shows that although the variability has the same trends as in the case of linear response, it is almost constantly increased by 5%.  相似文献   

Experimental study on seismic behavior of Un-Reinforced Masonry (URM) brick walls strengthened with shotcrete     

M. Shabdin  Nader K. A. Attari  M. Zargaran 《Bulletin of Earthquake Engineering》2018,16(9):3931-3956

In this study, the efficiency of conventional shotcrete technique for strengthening of Un-Reinforced Masonry (URM) walls was shown using an experimental program. In addition, in this program the possible benefit of using anchors for connecting the shotcrete reinforcement layer to the R/C foundation was studied. The experimental program consisted of testing five full scale specimens with two different height-to-length aspect ratios and so different failure modes, under in-plane cyclic loading conditions. Two specimens were tested as reference and others were strengthened on a single-face using shotcrete layer. According to the results, strengthening of URM walls using traditional shotcrete approach created a completely stiff panel and prevented the formation of cracks. The failure mode in both reference and strengthened short length walls was rocking and the shotcrete layer could increase the strength capacity, energy dissipation, and stiffness of wall due to yielding and rupture of steel bars anchored to the foundation. On the other hand, in strengthened long length walls, shotcrete layer increased the shear sliding capacity with no or small increasing in their rocking capacity. Therefore, the failure mode of strengthened walls converted from shear sliding to rocking, even in the specimen with anchorage system. The distributed type of anchorage system could not improve the strength capacity of long length wall. Anchorage system was able to improve the out-of-plane performance of strengthened walls.  相似文献   

Evolution of seismic hazard maps in Turkey     

S. Akkar  T. Azak  T. Çan  U. Çeken  M. B. Demircioğlu Tümsa  T. Y. Duman  M. Erdik  S. Ergintav  F. T. Kadirioğlu  D. Kalafat  Ö. Kale  R. F. Kartal  K. Kekovalı  T. Kılıç  S. Özalp  S. Altuncu Poyraz  K. Şeşetyan  S. Tekin  A. Yakut  M. T. Yılmaz  M. S. Yücemen  Ö. Zülfikar 《Bulletin of Earthquake Engineering》2018,16(8):3197-3228

A review on the historical evolution of seismic hazard maps in Turkey is followed by summarizing the important aspects of the updated national probabilistic seismic hazard maps. Comparisons with the predecessor probabilistic seismic hazard maps as well as the implications on the national design codes conclude the paper.  相似文献   

Damage classification and derivation of damage probability matrices from L’Aquila (2009) post-earthquake survey data     

A. Rosti  M. Rota  A. Penna 《Bulletin of Earthquake Engineering》2018,16(9):3687-3720

Post-earthquake damage data represent an invaluable source of information for the seismic vulnerability assessment of the exposed building stock, as they are a direct evidence of the actual buildings’ performance under real seismic events. This paper exploits a robust and homogeneous database of damage data collected after the 2009 L’Aquila (Italy) earthquake, to derive damage probability matrices for several building typologies representative of the Italian building stock. To this aim, the first part of the work investigates several issues related to the definition of damage to be associated with each inspected building. Different approaches and damage conversion rules are applied, pointing out advantages and weaknesses of each one. Considering the widespread seismic damage observed on masonry infill panels and partitions of reinforced concrete constructions, the impact of this type of non-structural damage on empirical damage and functional loss distributions is explored. The second part of the study proposes different possible interpretations of the repartition of the observed damage in the different damage levels, showing in some cases a bimodal trend. Two novel hybrid procedures are outlined and compared with the classical binomial approach for predicting the subdivision of damage in the different levels. The application of the proposed methodologies to the different building typologies allows the selection, for each one, of the method providing the best fit to empirical results. The parameters required for the application of the optimal approach are reported in the paper, so that results can be used for forecasting the expected seismic damage in sites with similar seismic hazard and exposed buildings.  相似文献   

Cyclic testing of a full-scale two-storey reinforced precast concrete wall-slab-wall structure     

E. Brunesi  S. Peloso  R. Pinho  R. Nascimbene 《Bulletin of Earthquake Engineering》2018,16(11):5309-5339

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Two uncertainties in simulating spatially varying seismic ground motions: incoherency coefficient and apparent propagation velocity     

M. R. Falamarz-Sheikhabadi  A. Zerva 《Bulletin of Earthquake Engineering》2018,16(10):4427-4441

The main focus of this paper is on uncertainties associated with the selection of the incoherency coefficient and apparent propagation velocity in the simulation of asynchronous seismic excitations based on the provisions of CEN [Comité Européen de Normalisation] (Eurocode 8: Design of structures for earthquake resistance—part 2: bridges, BS EN 1998-2:2005, Brussels, Belgium 2005). To this effect, the importance of utilizing appropriate values of these two parameters in the simulation of spatially varying seismic excitations is highlighted, and practice-oriented recommendations are provided for their selection. In addition, preliminary probability distributions are proposed for the consideration of the effect of uncertainty in the selection of the apparent propagation velocity for reliability (fragility) analyses. The effect of multi-support input motions on the seismic response of bridges is also discussed.  相似文献