共查询到18条相似文献，搜索用时 109 毫秒
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综合考虑远场类谐和地震动、近断层向前方向性地震动与近断层滑冲型地震动三类长周期地震动,对比分析不同类型长周期地震动的峰值与持时特征、低频特性、脉冲特性及反应谱特征,并探讨中、美、日、欧抗震设计谱在考虑长周期地震动影响方面的适用性。结果表明:长周期地震动的峰值、持时及反应谱特征明显区别于普通地震动,且三种长周期地震动之间亦存在显著差异;长周期地震动均具有低频脉冲特性,但不同类型长周期地震动在频域与时域内的能量分布规律不同;现行中、美、日、欧抗震设计谱均未综合考虑三类长周期地震动的影响,亟需开展综合考虑三类长周期地震动影响的抗震设计谱研究。 相似文献
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本文针对现行的抗震规范中设计反应谱应用范围只能到结构自振周期Ｔ≤３秒一现实问题，提出应用长周期地脉动的傅立叶振幅谱比值直接推算概率一地表长周期反应谱的方法。 相似文献
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介绍了沈阳金融中心超高层写字楼项目如何确定不同阻尼比的长周期设计地震动反应谱，从而避免在周期10s前出现反超现象。反应谱参数确定的原则是新设计反应谱外包或略高于原规范形式的设计反应谱。以“GB50011—2010《建筑抗震设计规范》”为基础，从两方面入手调整不同阻尼比的反应谱参数。一是修改反应谱下降段的形状，去掉直角坐标系下的直线下降段，将曲线下降段延长到原直线下降部分；二是修改下降段衰减指数。这样确定的反应谱在长周期部分不会过于保守，且调整参数的难度和工作量都大大降低。对于高于阻尼比5%和低于阻尼比5%的反应谱，在参数确定上也有不同考虑。 相似文献
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SMART-1台阵记录的长周期反应谱特性 总被引：3，自引：0，他引：3
利用台湾SMART－1台阵的数字强震仪加速度记录分析了同类场地上的地震动长周期分量特性，结果表明：同一次地震震中距基本相同的同类场地加速度反应谱短周期部分有较明显的差别，长周期部分则基本相同；震级和震中距对短周期反应谱影响明显，对长周期反应谱也有一定影响。最后将SMART－1台阳场地的平均谱与新的建筑抗震设计规范修订稿中提出的设计反应谱作了比较。 相似文献
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现有的设定地震方法主要有两种：加权平均法和最大概率法。本文首先简要介绍了这两种方法,然后以烟台地区一高层建筑为研究对象,分别采用加权平均法和最大概率法进行地震危险性分析,确定出设定地震震级、震中距以及具体空间位置,给出了两种方法的设定地震反应谱,最后对这两种方法所得结果的差异进行了对比和分析。结果表明：加权平均法所得反应谱将长周期处的安全性考虑在内,适用于中长周期建（构）筑物;最大概率法由于其长周期处谱值偏低,会增加长周期工程的危险性,不宜用于长周期工程,但对短周期建（构）筑物应用合理;对于自振周期不同的建筑工程应选用不同的地震危险性分析方法进行设计反应谱的确定。 相似文献
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基于日本KiK-Net、K-Net地震台网和太平洋地震工程中心（PEER）的14 713条地震动记录,比较了俯冲带地区浅壳上地幔地震、板内地震和板间地震的水平向地震动加速度反应谱阻尼修正系数（DMF）和位移反应谱阻尼修正系数（DMF）的差异,并进行了5%置信水平下的假设检验,探究了俯冲带地区不同地震类型对DMF的影响。结果显示:在大多数谱周期,不同地震类型的DMF存在统计意义上的显著差异;在低阻尼比中短周期时,加速度谱DMF和位移谱DMF基本相同;在高阻尼比长周期时,不同地震类型的加速度谱DMF差异大于位移谱DMF差异。研究表明:俯冲带地震水平向地震动DMF需要考虑不同地震类型的影响。 相似文献
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计算地震动长周期反应谱的转换模型和方法 总被引：1，自引：0，他引：1
为减小长周期反应谱的计算误差，本文提出一个计算长周期反应谱的转换模型和与之相应的精确计算方法。该模型以地震动的速度和位移为输入荷载，有利于对荷载信号中的长周期噪声进行有效的控制，能够有效提升长周期地震动反应谱的计算精度和可靠性。 相似文献
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为研究液化场地上建筑物承受地震作用的特性，本文利用11组液化场地实测记录，对液化场地的地震动特征进行了分析。结果显示，场地液化后，地表加速度幅值减小，长周期成分显著增多，记录中出现明显的 “尖刺” 。对比国内外抗震规范设计反应谱与液化场地实测加速度反应谱，分析得出:在短周期T＜0.3 s，规范设计反应谱值与实测记录反应谱基本一致；在中长周期段0.3 s＜T＜1.5 s，规范反应谱值明显低于实测记录反应谱值；在长周期段T＞1.5 s，规范设计谱较实测记录反应谱值略低。基于5种数值方法模拟的液化场地地震动结果显示:周期T＜1.0 s时，数值计算的反应谱值基本高于液化场地实测反应谱值，或与之吻合；而周期T＞1.0 s时，数值计算的反应谱值均低于液化场地实测反应谱值。 相似文献
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Gian Michele Calvi 《地震工程与结构动力学》2018,47(13):2627-2643
For several decades, seismologists and engineers have been struggling to perfect the shape of design spectra, analyzing recorded signals, and speculating on probabilities. This research effort produced several improvements, for example, suggesting to adopt more than one period to define a spectral shape or proposing different spectral shapes as a function of the return period of the design ground motion. The spectral shapes recommended in most modern codes are driven by considerations on uniform hazard; however, the basic assumption of adopting essentially three fundamental criteria, ie, constant acceleration at low periods, constant displacement at long periods, and constant velocity in an intermediate period range, has never been really questioned. In this opinion paper, the grounds of a constant velocity assumption is discussed and shown to be disputable and not physically based. Spectral shape based on different logics are shown to be potentially consistent with the experimental evidence and to lead to possible differences of 100% in terms of displacement and acceleration demand in the wide intermediate period range that characterizes the vast majority of structures. In this framework, the historical development of linear and nonlinear spectra is critically revisited, proposing a novel original way of defining seismic demand. 相似文献
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本文收集了从南北地震带川滇甘陕地区263个有详细场地资料的强震台站获得的802组强震动记录，按照场地、震级和震中距等因素统计分析了竖向与水平向加速度反应谱比的形状以及不同场地、震级和震中距下不同周期段内的谱比平均值，并与建筑抗震规范GB50011—2010规定的0.65进行了比较。结果表明:竖向与水平向加速度反应谱比受场地、震级和震中距等因素的影响； Ⅰ类和Ⅱ类场地在全周期段的谱比均值基本上大于0.65；无论何种分组情况谱比均值在0.1—1.0 s周期范围内基本低于定值0.65，周期大于1.0 s的谱比均值基本上远高于0.65。因此对于大部分抗震规范直接把竖向地震作用取为水平向地震作用的0.65倍，有待商榷。本文建议根据水平向反应谱的标定方式来确定现有竖向强震动记录的竖向地震作用。 相似文献
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为考查远场地震动的场地相关性并评价一些场地特性分析方法的适用性,采用不同方法对汶川地震山东省12个远场台站的强震记录进行了分析.选取台站分别位于按建筑抗震设计规范(CBC)场地划分中的Ⅰ—Ⅲ类场地上.地震动记录的分析方法包括傅里叶幅值谱法,地震反应谱法,水平与竖向谱比率法,参考点谱比率法,以及尾波分析等.结果表明,按傅里叶幅值谱法,地震反应谱法,水平与竖向谱比法计算得到的卓越周期均远大于台站场地的卓越周期,不同方法得到的结果之间也有较大差别,且主要反映长周期地震动的卓越频率;参考点谱比率法的结果未反映地震动的卓越周期,也与场地的卓越周期差别较大;对完整记录尾波分析所得的结果比较接近场地的卓越周期.希望本文能为考虑远场地震作用时设计谱的建立,以及场地特性估计时地震动分析方法的选取提供参考依据. 相似文献
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The next generation of seismic design codes, especially those adopting the framework of performance‐based design, will include the option of design based on displacements rather than forces. For direct displacement‐based design using the substitute structure approach, the spectral ordinates of displacement need to be specified for a wide range of response periods and for several levels of damping. The code displacement spectra for damping values higher than the nominal value of 5% of critical will generally be obtained, as is the case in Eurocode 8 and other design codes, by applying scaling factors to the 5% damped ordinates. These scaling factors are defined as functions of the damping ratio and, in some cases, the response period, but are independent of the nature of the expected ground shaking. Using both predictive equations for spectral ordinates at several damping levels and stochastic simulations, it is shown that the scaling factors for different damping levels vary with magnitude and distance, reflecting a dependence of the scaling on the duration of shaking that increases with the damping ratio. The options for incorporating the influence of this factor into design code specifications of displacement response spectra are discussed. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
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Anibal Ojeda Samuel Martinez Maria Bermudez Kuvvet Atakan 《Soil Dynamics and Earthquake Engineering》2002,22(9-12):791-797
The new accelerographic network of Santa Fe de Bogotá is composed of 29 three-component stations with sensors at the surface and three additional six-component borehole stations with three sensors at the surface and three at depth (115, 126 and 184 m). In total, 32 stations have been operative in the metropolitan area of Bogotá since 1999. During this period of time, a significant number of weak motion are recorded and used for a preliminary analysis of local site effects. Using the SH-wave response spectra we verify the behavior of the different seismic zones proposed by the previous microzonation study of the city. A comparison between normalized SH-wave response spectra and the normalized design spectra for each zone clearly depicts that parts of the design spectra should be revised, as well as the boundaries between different zones may require some changes. The spectral amplification levels reach up to a factor of 5. The predominant periods obtained by the amplification spectra in different stations in the city, show variability from 0.3 to 3.0 s. A comparison is also made between the predominant periods obtained using H/V spectral ratios of microtremors and those using weak motion. In general, microtremors tend to predict slightly lower values of dominant periods than those calculated by the weak motion spectra. However, there is a general correlation between the two data sets. Using the data recorded by one of the borehole station, an equivalent linear seismic response analysis was conducted. The modeled and recorded response spectra show similarities in period peaks, however, the modeled soil amplification is underestimated for periods less than 0.8 s. Since the available record is weak motion which represents mostly the linear response of the soils, further analysis is required. 相似文献
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The characterisation of the seismic hazard input is a critical element of any seismic design code, not only in terms of the absolute levels of ground motion considered but also of the shape of the design spectrum. In the case of Europe, future revisions of the seismic design provisions, both at a national and a pan‐European level, may implement considerable modifications to the existing provisions in light of recent seismic hazard models, such as the 2013 European Seismic Hazard Model. Constraint of the shape of the long‐period design spectrum from seismic hazard estimates on such a scale has not been possible, however, owing to the limited spectral period range of existing ground motion models. Building upon recent developments in ground motion modelling, the 2013 European Seismic Hazard Model is adapted here with a new ground motion logic tree to provide a broadband Probabilistic Seismic Hazard Analysis for rock sites across a spectral period range from 0.05 seconds to 10.0 seconds. The resulting uniform hazard spectra (UHS) are compared against existing results for European and broadband Probabilistic Seismic Hazard Analysis and against a proposed formulation of a generalised design spectrum in which controlling parameters can be optimised to best fit the uniform hazard spectra in order to demonstrate their variability on a European scale. Significant variations in the controlling parameters of the design spectrum are seen both across and within stable and active regions. These trends can help guide recalibrations of the code spectra in future revisions to seismic design codes, particularly for the longer‐period displacement spectrum. 相似文献
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Luis D. Decanini Laura Liberatore Fabrizio Mollaioli 《Soil Dynamics and Earthquake Engineering》2003,23(6):455-471
The results of a research concerning the characterization of elastic and inelastic displacement spectral demand as a function of magnitude, source-to-site distance, and soil type are presented. The displacement spectra were computed for single degree of freedom systems subjected to a large set of strong ground motion records.In the elastic case, design displacement spectra, modeled in a simplified way with a bilinear shape in the period range 0–4 s, are then proposed for the estimation of the displacement demand to structures located on different local soil condition, at different distance from the causative fault, and for different levels of magnitude. In order to evaluate the reliability of the proposed design displacement spectra, probabilistic displacement spectra corresponding to different levels of probability of non-exceedance were also carried out.The inelastic displacement demand to elasto-plastic systems was analyzed through the ratio between inelastic and elastic spectral displacements. Simplified relationships of the inelastic displacement ratio are then proposed as a function of displacement ductility, soil condition and period of vibration. Finally, as a comparison, the inelastic displacement ratios were also estimated considering other constitutive models. 相似文献