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本文描述强震地面运动持续时间的几个经验模型。我们将运动函数ｆ（ｔ）的持续时间定义和积分∫＾１０ｆ＾２（τ）ｄτ达到其最终数值的重要部分的时间间隔的总和。此外ｆ（ｔ）为加速速度、速度或位移。所有记录均通过１２个窄滤波器进行带通滤波，而强震地面运动的持续时间系在这些频带分别进行研究。除子震级、震中距等传统参数之外，还考虑其他三个参数，这些参描述围绕着记录台站的沉积盆地的几何形状。文中说明沉积物的存在怎 相似文献
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修建于地震区的核电站,在进行设计时如何确定设计地震参数是很重要的。 众所周知,为了工程抗震设计,必须以某种形式给出预测的地震地面运动。实际上这应当是一个统计学问题,因为地震地面运动是震源特性、地震波传播途经介质特性以及场地条件等一系列因素综合影响的结果,不可能预先唯一确定,世界上找不到两条完全相同的强震加速度记录就是明证。因此,在设计建筑物时预测未来可能产生的地震地面运动,就不能不借助于已有的强震记录:或利用它们的统计特征,或利用一组有代表性的强震记录再加上对于其它参与条件的分析判断来解决。 相似文献
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《地震研究》1982,(3)
强震观测可以记录复杂的地震破环作用的全过程,提取强地面运动和结构物破环的信息,是研究地震工程、地震破裂过程和地壳构造等有关问题的基础。因此,加强地震观测工作,在主要地震区布设强震加速度仪是当前首要而迫切的任务。另外,某一给定地点的地面运动记录,不仅取决于震源机制的特性,还取决于从震源到该地点影响地面运动特性的各种因素,如地震波传播途径的特征、局部地形、土壤条件以及土壤液化等。单个的地面运动记录虽然也能提供与这些因素有关的资料,但它不能给出地面运动局部变化的充分资料。因此选择有利地点,布设密集台阵是强震仪台阵的发展趋势。本文在确定布设强震仪台阵必须遵循的一般原则和近场强地面运动研究内容的前提下,以云南滇西实验场(25°—27°30＇N,99°—101°E)作为布设强震仪台阵的地区,采用了主台阵和局部效应台阵两种型式,阐述了不同类型台阵的设计目的并给出了各类台阵结构的布设图。 相似文献
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本文通过对1976年唐山地震及其7.1级强余震宏观现象的分析,指出强震引起地面运动及建筑物的倒塌具有一定的优势方向。但同一地区不同强震引起的地面运动及建筑物的倒塌方向常不相同。发现强震高烈度区存在许多震害轻重相间的异常条带,其延伸方向大体上与地震断层平行。这种规律,给地震危险区内的各类工程、土木建筑的抗震设计提供了一些新的依据。 相似文献
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以反应谱和功率谱密度函数表征的强震运动的统计特性 总被引：1，自引：0，他引：1
文中利用我国海城和唐山地震１９０条强震记录和美国西部１３８条强震记录研究了以反应谱和功率谱密度函数表征的强震运动的统计特性。反应谱用最大地面加速度归一化，即表为谱放大系数，功率谱密度函数用金井清谱描述。文中研究了参数的统计值和依赖性，以及谱放大系数和金井清谱参数与场地条件、震源和震中距等之间的相关性，分析比较了中美两国强震运动谱的统计特性，并对我国地震工程应用的强震运动谱的统计参数值的选取提出了建议。 相似文献
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地震工程界对随机地震动已进行了40多年的研究，提出了多种较好的随机过程模型，其中最具代表性的是日本学者金井清(Kanai)(1961)提出的过滤白噪声模型．进一步，欧进萍等(1991)在评述既往随机模型基础上，提出了地震地面运动的过滤有色噪声模型．然而，这些模型都存在一个最大的问题，就是不能合理确定模型中反映地震强度的参数————谱强度因子S0.
随机地震动研究的基础是强震记录，基于地面强震记录，人们对地震地面运动随机模型进行了大量的研究，其中对基岩地震动的模拟还有很多需要解决的问题．本文在基岩强震记录统计基础上，研究基岩地震动的随机模型和模型参数，为建立工程抗震的合理地震动模型奠定基础． 相似文献
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《地震地磁观测与研究》2016,(2)
通过使用Iprocess等软件,分析浙江省强震台网获取的2014年度浙江省震级最大的温州市文成、泰顺交界M 4.2地震的地面运动数据,发现各强震台站地面运动加速度峰值等数据在一致性、准确性、时效性方面取得较好结果,因台站土层结构等场地环境及地震计等设备参数的不同等因素,加速度峰值等数据也存在一定差异。本次震例的地面运动波形数据的分析结果也说明,浙江省地震局较好地完成了本省强震台网的建设任务。 相似文献
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根据第一作多年来从事用断裂动力学的解析解来表示强震地面运动的振幅、速度、加速度,所得的结果与两次名强震地面运动的记录进行了比较,二符合较好,故提出应用断裂动力学的研究成果来制定确定性的地震烈度区划方法的初步探讨意见。 相似文献
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根据新疆喀什地区两次地震中新疆强震台网记录的加速度数据,分析介绍了强震观测资料的常规处理和使用,并简介了强震观测资料在研究地面运动特征中的作用。 相似文献
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Nikos Gerolymos Marios Apostolot George Gazetas 《地震工程与工程振动(英文版)》2005,4(2):213-228
Under strong seismic excitation, a rigid block will uplift from its support and undergo rocking oscillations which may lead to （complete） overturning. Numerical and analytical solutions to this highly nonlinear vibration problem are first highlighted in the paper and then utilized to demonstrate how sensitive the overturning behavior is not only to the intensity and frequency content of the base motion, but also to thc presence of strong pulses, to their detailed sequence, and even to their asymnletry. Five idealised pulses capable of representing ＂rupture-directivity＂ and ＂fling＂ affected ground motions near the fault, are utilized to this end ： the one-cycle sinus, the one-cycle cosinus, the Ricker wavelet, the truncated （T）-Ricker wavelet, and the rectangular pulse ＂Overturning-Acceleration Amplification＂ and ＂Rotation＂ spectra are introduced and presented. Artificial neural network modeling is then developed as an alternative numerical solution. The neural network analysis leads to closed-form expressions for predicting the overturning failure or survival of a rigid block, as a function of its geometric properties and the characteristics of the excitation time history. The capability of the developed neural network modeling is validated through comparisons with the numerical solution. The derived analytical expressions could also serve as a tool for assessing the destructiveness of near-fault ground motions, for structures sensitive to rocking with foundation uplift. 相似文献
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Influence of time‐varying frequency content in earthquake ground motions on seismic response of linear elastic systems 
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下载免费PDF全文 Earthquake ground motion records are nonstationary in both amplitude and frequency content. However, the latter nonstationarity is typically neglected mainly for the sake of mathematical simplicity. To study the stochastic effects of the time‐varying frequency content of earthquake ground motions on the seismic response of structural systems, a pair of closely related stochastic ground motion models is adopted here. The first model (referred to as ground motion model I) corresponds to a fully nonstationary stochastic earthquake ground motion model previously developed by the authors. The second model (referred to as ground motion model II) is nonstationary in amplitude only and is derived from the first model. Ground motion models I and II have the same mean‐square function and global frequency content but different features of time variation in the frequency content, in that no time variation of the frequency content exists in ground motion model II. New explicit closed‐form solutions are derived for the response of linear elastic SDOF and MDOF systems subjected to stochastic ground motion model II. New analytical solutions for the evolutionary cross‐correlation and cross‐PSD functions between the ground motion input and the structural response are also derived for linear systems subjected to ground motion model I. Comparative analytical results are presented to quantify the effects of the time‐varying frequency content of earthquake ground motions on the structural response of linear elastic systems. It is found that the time‐varying frequency content in the seismic input can have significant effects on the stochastic properties of system response. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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Characterization of Earthquake Strong Ground Motion 总被引：1，自引：0，他引：1
— Some underwater landslides are triggered by strong ground motions caused by earthquakes. This paper reviews current concepts and trends in the characterization of strong ground motion. Improved empirical ground motion models have been derived from a strong motion data set that has grown markedly over the past decade. However, these empirical models have a large degree of uncertainty because the magnitude-distance-soil category parameterization of these models often oversimplifies reality. This reflects the fact that other conditions that are known to have an important influence on strong ground motions, such as near-fault rupture directivity effects, crustal waveguide effects, and basin response effects, are not treated as parameters of these simple models. Numerical ground motion models based on seismological theory that include these additional effects have been developed and extensively validated against recorded ground motions, and used to estimate the ground motions of past earthquakes and predict the ground motions of future scenario earthquakes. 相似文献
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A new spatial coherence model and analytical coefficients for multi-support response spectrum combination 总被引：1，自引：0，他引：1
In this paper, a new spatial coherence model of seismic ground motions is proposed by a fi tting procedure. The analytical expressions of modal combination (correlation) coeffi cients of structural response are developed for multi-support seismic excitations. The coeffi cients from both the numerical integration and analytical solutions are compared to verify the accuracy of the solutions. It is shown that the analytical expressions of numerical modal combination coeffi cients are of high accuracy. The results of random responses of an example bridge show that the analytical modal combination coeff icients developed in this paper are accurate enough to meet the requirements needed in practice. In addition, the computational effi ciency of the analytical solutions of the modal combination coeff icients is demonstrated by the response computation of the example bridge. It is found that the time required for the structural response analysis by using the analytical modal combination coeffi cients is less than 1/20 of that using numerical integral methods. 相似文献
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海域地震动是海洋工程建设必须考虑的因素,近年来学者们对海域地震动做了大量研究,这些研究涵盖海域地震动的各方面。为总结对海域地震动特性的研究成果并分析存在的问题,分类阐述了不同学者对海域地震的研究结果。根据采用的研究方法可分为解析方法、数值模拟方法和统计方法。在此基础上,归纳了不同研究方法得出的海域地震动场地影响与传播规律的结论:解析方法与数值方法得出的结论侧重于分析海域地震动受海水、淤泥沉积层与地形等场地条件的影响;统计方法得出的结论集中在海域地震动与陆地地震动在地震动特性与传播规律方面的差异,这些结论可以为采用相同方法的研究提供参考。最后,对当前研究中存在的问题进行探讨,由于数据相对匮乏,导致缺少对海域地震动与陆域地震动差异的定量分析,也缺少对海域地震动不确定性的分析。 相似文献
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How to select the adequate real strong earthquake ground motion for seismic analysis and design of trucures is an essential problem in earthquake engineering research and practice.In the paper the concept of the severest design ground motion is proposed and a method is developed for comparing the severity of the recorded strong ground motions.By using this method the severest earthquake ground motions are selected out as seismic inputs to the structures to be designed from a database that consists of more than five thousand significant strong ground moton records collected over the world.The selected severest ground motions are very likely to be able to drive the structures to their critical response and thereby result in the highest damage potential.It is noted that for different structures with diffferent predominant natural periods and at different sites where structures are located the severest design ground motions are usually different.Finally.two examples are illustrated to demonstrate the rationality of the concept and the reliability of the selected design motion. 相似文献
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A model for investigations of ground motions due to continuously moving loads with constant and time-varying amplitudes is presented. The vertical displacements excited by moving load areas are obtained at a fixed observation point at the surface of the three-dimensional halfspace in time domain. The load is moving along a straight line with constant speed. To solve this nonaxisymmetric, initial boundary value problem a semi-analytical, discretized model is developed. It is based on Green's functions for a suddenly applied, stationary surface point load with Heaviside time dependency. These functions, also called influence functions of the halfspace, are valid for any homogeneous, isotropic and linear-elastic medium. The principle of superposition is used. Results are shown for the transient and the steady-state ground motions, and they are compared with analytical solutions. The load speed is varied in the subcritical range up to the propagation velocity of Rayleigh-waves. 相似文献
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实际记录到的真实地震动在工程结构的抗震研究、分析和设计中往往作为一种施加到结构上使结构振动，直至破坏的地震荷载．如何合理选择真实的地震动记录作为研究结构地震反应的输入，一直是国内外抗震研究和设计中引人关注的重要问题．本文首先提出了最不利设计地震动的概念；然后在收集到的国内外5000余条被认为有重要意义的地震动记录基础上，利用综合估计地震动潜在破坏势的方法，对４种场地类型分别给出了长周期、短周期和中周期结构的国内外最不利设计地震动；最后通过几类不同结构的地震反应分析，初步验证了本文所确定的最不利设计地震动的可靠性和合理性． 相似文献
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近年来的强震地震观测资料研究显示,近断层地面运动具有区别于远场地震动的显著特征。在收集世界范围内近断层观测记录的基础上,按场地和震级进行分类,采用统计分析的方法研究了近断层地震动的峰值、反应谱谱值和持时特征。研究结果表明,由于方向性效应的影响,两个水平分量的峰值存在显著差异,反应谱的谱值更显著,震级对地震动持时的影响比断层距的影响要大得多,在此基础上,建立了近断层地震动水平向和竖向分量持时的回归关系式,并与其他研究者进行对比,说明了其合理性,为进一步研究提供参考。 相似文献
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At present, dense strong motion observation networks have been established in Japan. One of the important findings based on these networks is that strong ground motions are quite site-dependent. Characteristics of observed ground motions at nearby stations can exhibit a significant variation, even when the stations are within several hundreds of meters. These observations raise one important question; if characteristics of strong ground motions exhibit large variations even for smaller regions, we should be concerned about the application of observed or predicted ground motions for the assessment of structures. In particular, if ground-motion parameters such as PGA, PGV, Spectral Intensity, etc., exhibit large variations for smaller regions, their use for the seismic design and practice will be subject to restriction. In other words, the evaluation of variation of these parameters is an important issue. From such a point of view, the authors investigated the variation of observed ground motions within a very small distance in this study. First of all, fifteen couples of adjacent strong motion stations in Japan, where the distance is within 100 m, were listed up based on our field reconnaissance. Then, microtremor measurements were carried out at each of the station pairs. Next, variation of recorded earthquake ground motions for the station pairs was examined based on various ground motion parameters and response spectra. Moreover, we investigated the key factor which is affecting the variation of observed ground motions. 相似文献