共查询到19条相似文献，搜索用时 203 毫秒
1.
利用复合震源模型和人工合成地震图的算法， 以1679年三河——平谷Ms8.0地震为例，计算了北京地区的宽频带强地面运动. 其结果可为今后该地区的地震危险性评估和工程抗震提供一定的物理参数. 通过考察该地区的地质与地球物理区域背景， 利用计算机数值模拟的方法, 对北纬39.3deg;~41.1deg;东经115.35deg;~117.55deg;所围限的北京范围进行了设定地震的仿真模拟，并合成了强地面运动. 通过分析影响强地面运动的几个关键因素，给出了北京地区强地面运动峰值加速度和速度分布特征，比较了合成强地面运动记录与通过衰减关系计算所得的结果. 同时，还对复合震源模型的优点和局限性给出了充分的讨论. 利用数值模拟方法所得的较为真实的强地面运动参数，即加速度、速度、位移和时程特征，可为北京地区工程建设的抗震设计、救援设施的选址、以及金融及保险部门的风险性评估提供一定的依据. 相似文献
2.
与建筑抗震设计规范相对应的地面地震动随机模型参数研究 总被引：4，自引：0，他引：4
根据《建筑抗震设计规范(GB50011—2001)》的反应谱曲线,确定了基于Clough-Penzien修正过滤白噪声模型的参数取值。采用时间包络函数考虑地震的非平稳特性,根据加速度峰值等效原则迭代计算得到地面的加速度功率谱密度曲线,然后通过曲线拟合得到与规范各种地震烈度、场地类别和设计地震分组相对应的谱参数。计算结果表明,与规范相对应的加速度功率谱密度曲线呈双峰型,Clough-Penzien谱能较好地拟合其曲线形状。最后给出了规范各种工况下的地面加速度功率谱参数值,为随机抗震计算分析提供了依据。 相似文献
3.
场地类型对反应谱平台值的影响 总被引：2，自引：1，他引：1
文中在总结一些学者研究基础上,利用土层地震反应分析的一维等效线性化波动方法,以建筑抗震设计规范规定的反应谱为目标谱,合成不同加速度峰值和特征周期加速度时程曲线共28条,将其作为土层地震反应分析的输入地震动,选取和构造了四种场地类型的225个土层剖面,计算了不同土层剖面在不同地震动输入下的设计反应谱的平台值.基于统计分析... 相似文献
4.
本文以二滩地区为例,介绍如何结合地震危险性分析的结果,采用理论模拟方法估计工作地区近场强地面运动情况,为工程抗震设计提供必需的地面运动动力学参数。 文中采用理论方法计算剪切位错点源的格林函数;根据断裂动力学模型、近场地面峰值加速度衰减曲线和场地附近的加速度谱来标定震源模型;计算了若在坝区附近发生Ms=6.2级地震时场地的综合地震图、加速度傅氏谱和反应谱等。由理论模拟计算的峰值加速度衰减曲线和观测结果符合较好。在震中距为20km处的加速度谱的截止频率fmax与观测值相吻合（约为8 Hz左右）,相应的峰值加速度为211cm/s2,振动持续时间为3.4秒。 相似文献
5.
为对具有传统文化的仿古建筑在不破坏其原有建筑风貌的基础上进行抗震加固,将隔震技术应用于仿古建筑。采用数值模拟的方法研究仿古建筑隔震,建立隔震与非隔震两种有限元计算分析模型,并对加固前、后模型进行动力时程分析。通过输入不同频谱的El Centro Site波、Taft波和RH1TG055波,对比分析两种模型在地震作用下的位移、加速度时程曲线。结果表明：采用隔震技术加固方案后,结构的地震响应得到明显的降低,从而显著地提高了结构的抗震能力。利用该方法加固,节约造价,施工方便,可供同类工程参考。 相似文献
6.
关于上海市<建筑抗震设计规程>中长周期设计反应谱的讨论 总被引：11，自引：1，他引：10
在上海市地方标准《建筑抗震设计规程》（ＤＢＪ０８－９－９２）及其１９９６年局部修订增补版本中、对上海市类场地建筑结构的地震影响系数进行了特殊规定,并将结构自振 周期延长到１０ｓ,同时给出了三条加速度时程用于时程分析。本文主要针对《建筑抗震设计规程》中有关长周期反应谱部分的规定,根据国内外的研究现状,进行一些探讨,指出所提供的一条人造地震动时程和两条国外加速度记录用于上海市ＩＶ类场地长周期建筑结构的 相似文献
7.
为了研究地震时地面运动加速度作用下高层房屋建筑深基坑支护承压结构的局部抗震性能,针对高层房屋建筑深基坑支护承压结构进行局部抗震性试验分析.采用有限元软件对某高层房屋建筑深基坑工程进行分析,构建高层房屋建筑深基坑支护承压结构有限元计算模型.利用地震模拟振动台,分别输入0.4g、0.5g、0.6g的地震时地面运动加速度,测... 相似文献
8.
本文利用Ｍｏｎｔｅ－Ｃａｒｌｏ数字模拟原理，以同一集系的多条地震加速度时程为输入，利用作者提出的考虑结构低周疲劳特性，首超破坏与累积损伤破坏合一的地震破坏准则，通过时程反应分析，直接统计反应量的随机特征来寻求结构的抗震可靠度，避免了建立地面运动简化模型和求解强非线性随机振动问题带来的近似与误差，在可靠度分析中采用了一次二阶矩的验算点法，将结构抗震可靠性统一到可靠指标β上来分析，便于在工程中实际运用 相似文献
9.
根据强震动观测、实验研究与数值模拟结果表明,山脊地形对地震动具有显著影响.文章基于汶川地震主震及余震的三个地形效应观测台阵记录的三分量地震动加速度时程,经基线校正后计算得到各观测点的地面峰值加速度、峰值加速度比和反应谱比,分析山脊地形对地震地面运动的影响.结果表明:山脊地形对地震地面运动的影响显著,其地形地震效应随山脊地形的不同而变化,且地形效应具有方向性;水平向地形效应显著于垂直向;谱比是周期相关的,在所分析的周期范围内谱比不总是大于1．0. 相似文献
10.
邢台地区设定地震事件烈度影响 总被引：1，自引：1，他引：0
通过邢台地区历史地震烈度资料分析,得到该地区烈度—频率灾害曲线及地震风险。以地震地质资料理论为基础,结合河北省城市活断层探测成果、地壳结构等资料,确定2个设定地震事件。采用复合震源模型,模拟合成强地面运动,并基于强地面运动模拟结果,分析邢台地区地震影响烈度,为今后该地区建筑物抗震设防、避难场所选址、震后救援以及地震保险风险评估提供参考依据。 相似文献
11.
计算机仿真模拟设定地震断层动态破裂传播和近断层强地表运动响应的结果表明， 对于特征地震而言，近断层附近的地表运动特征与断层破裂传播的方向性有着强烈的依赖关系. 当场地（观测点）至断层的距离给定时，正向于破裂传播方向的场地（场地A）的地表质点运动（位移、速度、加速度），远远大于震中附近（场地B）和反向于破裂传播方向的场地（场地C）的地表质点运动，而且沿断层垂直分量所辐射的SH波的传播起到了主导作用. 对应于场地A，B和C，统计分析结果表明，峰值加速度的几何平均值之比为2.15:1.5:1， 而且各自的均方差分别为0.12, 0.11和0.13. 如果将所得的研究结果应用于概率地震危险性分析中，对于较低的年超越频度，近断层附近的地表峰值加速度的估算值可下降15%~30%. 因此，考虑到断层破裂传播方向性对地表运动的影响，区域衰减曲线的回归分析模型应该给予恰当的修正. 相似文献
12.
Ludovica Elefante Fatemeh JalayerIunio Iervolino Gaetano Manfredi 《Soil Dynamics and Earthquake Engineering》2010
The results of seismic hazard disaggregation can be used to assign relative weights to a given ground motion record based on its corresponding magnitude, distance and deviation from the ground motion prediction model (epsilon) in order to make probability-based seismic assessments using non-linear dynamic analysis. In this paper, the implications of using the weighted ground motion records are investigated in terms of the mean annual frequency of exceedance of the critical component-based demand to capacity ratio in an existing reinforced concrete structure using both the peak ground acceleration and the first-mode spectral acceleration as intensity measures. It is demonstrated how site-specific seismic hazard disaggregation can be used in order to obtain the conditional probability distribution for a relevant ground motion characteristic given the chosen intensity measure. Distinguished by the amount of structural analysis required, two alternative non-linear dynamic analysis procedures, namely the cloud and the stripes method are implemented. The weighted cloud and the weighted stripes methods are then introduced as analysis procedures which modify the structural response to the selected ground motion records by employing the information provided from the seismic hazard analysis. It is demonstrated that the resulting annual frequencies based on weighted records are comparable to those obtained by using vector-valued intensity measures, while requiring less computational effort. 相似文献
13.
The conditional spectrum (CS, with mean and variability) is a target response spectrum that links nonlinear dynamic analysis back to probabilistic seismic hazard analysis for ground motion selection. The CS is computed on the basis of a specified conditioning period, whereas structures under consideration may be sensitive to response spectral amplitudes at multiple periods of excitation. Questions remain regarding the appropriate choice of conditioning period when utilizing the CS as the target spectrum. This paper focuses on risk‐based assessments, which estimate the annual rate of exceeding a specified structural response amplitude. Seismic hazard analysis, ground motion selection, and nonlinear dynamic analysis are performed, using the conditional spectra with varying conditioning periods, to assess the performance of a 20‐story reinforced concrete frame structure. It is shown here that risk‐based assessments are relatively insensitive to the choice of conditioning period when the ground motions are carefully selected to ensure hazard consistency. This observed insensitivity to the conditioning period comes from the fact that, when CS‐based ground motion selection is used, the distributions of response spectra of the selected ground motions are consistent with the site ground motion hazard curves at all relevant periods; this consistency with the site hazard curves is independent of the conditioning period. The importance of an exact CS (which incorporates multiple causal earthquakes and ground motion prediction models) to achieve the appropriate spectral variability at periods away from the conditioning period is also highlighted. The findings of this paper are expected theoretically but have not been empirically demonstrated previously. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
14.
A probabilistic representation of the entire ground‐motion time history can be constructed based on a stochastic model that depends on seismic source parameters. An advanced stochastic simulation scheme known as Subset Simulation can then be used to efficiently compute the small failure probabilities corresponding to structural limit states. Alternatively, the uncertainty in the ground motion can be represented by adopting a parameter (or a vector of parameters) known as the intensity measure (IM) that captures the dominant features of the ground shaking. Structural performance assessment based on this representation can be broken down into two parts, namely, the structure‐specific part requiring performance assessment for a given value of the IM, and the site‐specific part requiring estimation of the likelihood that ground shaking with a given value of the IM takes place. The effect of these two alternative representations of ground‐motion uncertainty on probabilistic structural response is investigated for two hazard cases. In the first case, these two approaches are compared for a scenario earthquake event with a given magnitude and distance. In the second case, they are compared using a probabilistic seismic hazard analysis to take into account the potential of the surrounding faults to produce events with a range of possible magnitudes and distances. The two approaches are compared on the basis of the probabilistic response of an existing reinforced‐concrete frame structure, which is known to have suffered shear failure in its columns during the 1994 Northridge Earthquake in Los Angeles, California. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
15.
工程场地的设计地震动参数,目前多用概率地震危险性分析的方法给出。场地的地震基本烈度以设计基准期T=50年、加速度超越概率P=0.1的标准确定。本文根据广东省数地地震危险性分析结果结合我国常见的砖混结构的地震动参数的优化决策,认为上述标准宜取为T=50年、P=0.05—0.1。 相似文献
16.
R. M. W. Musson 《Bulletin of Earthquake Engineering》2009,7(3):575-589
It might be thought that an empirical ground motion prediction model has only to describe the variations in the input data
set as accurately as possible in order to be useful, with the proviso that the data set is reasonably extensive and well-selected.
If the model is to be used in probabilistic seismic hazard assessment, however, the model will probably be subject to extrapolation
beyond the parameter space within which it was constructed, especially for hazard at low annual probabilities. In this case,
features of the model, especially its functional form, may turn out to have unexpected and undesirable implications. The end
result can be conclusions about the hazard that are clearly not in accordance with commonsense. In this study, two test cases
are used to examine the application of some recent ground motion models to probabilistic hazard studies. Problems are found
that suggest that, although a ground motion model may be a correct representation of its data set, the effects of the functional
form applied can be such that it becomes doubtful whether the model should be used for probabilistic hazard purposes. 相似文献
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为研究黏滞阻尼器对高层钢结构地震易损性的影响,基于Open SEES有限元分析平台,建立一个25层钢框架结构以及同尺寸附着黏滞阻尼器的钢框架结构,对两个钢框架结构以地震动峰值加速度(PGA)作为地震动强度指标,以结构最大层间位移角θmax为工程需求参数,从太平洋地震工程研究中心(PEER)中选取了15条地震动记录,分别对两个结构进行增量动力分析(Incremental Dynamic Analysis,IDA),建立结构的IDA曲线簇。结合地震易损性分析,对分析结果进行对数拟合,构筑两个结构的连续易损性曲线,并进一步提出用贝塔分布函数将结果转化为地震动参数-震害指数概率密度函数的概率表达方式,可以更加直观简便地观察到黏滞阻尼器显著的减震效果。该表达方法具有直观性,研究成果可为既有结构的地震灾害风险评估等提供简明且有力的分析方法。 相似文献