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1.
Tsuneo Katayama 《地震工程与结构动力学》1982,10(1):149-163
A regression analysis was made on 277 acceleration response spectra computed from Japanese accelerograms by subdividing the data into discrete categories. Five magnitude and distance categories, and four ground condition categories were used. The maximum absolute acceleration amplitude is predicted as a product of three factors, each representing a weighting factor for magnitude, distance and ground condition category at each of the 18 response spectrum periods from 0·1 s to 4 s at a damping value of 5 per cent of critical. A method was then developed to evaluate seismic hazard in terms of acceleration response spectrum by using the prediction model and the seismicity data, and it was applied to obtain seismic macro-zoning maps of Japan which are dependent on the natural period of a structure. The results of the analysis indicated that a single seismic zoning map may not be sufficient to cover a variety of structures with a wide range of periods because the expected spectral shape differs according to the seismicity of the area. 相似文献
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本文用数值积分法,对RDZ1-12-66型自动触发电流计记录式强震仪的幅频响应失真进行校正。并采用高通数字滤波的方法,修正加速度图的零线.为此编制了计算机程序,绘制了修正后的加速度、速度和位移时程曲线.计算了修正前后加速度图的傅氏谱。同时,对这些结果加以讨论。 修正后的加速度图,精确地表示了仪器基本频带在0.09HZ和25HZ之间的绝对地面加速度。 相似文献
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Representation of near-fault pulse-type ground motions 总被引：7，自引：3，他引：4
Near-fault ground motions with long-period pulses have been identified as critical in the design of structures. To aid in the representation of this special type of motion, eight simple pulses that characterize the effects of either the fling-step or forward-directivity are considered. Relationships between pulse amplitudes and velocity pulse period for different pulses are discussed. Representative ratios and peak acceleration amplification can exhibit distinctive features depending on variations in pulse duration, amplitude and the selected acceleration pulse shape. Additionally, response spectral characteristics for the equivalent pulses are identified and compared in terms of fixed PGA and PGV, respectively. Response spectra are strongly affected by the duration of pulses and the shape of the basic pulses. Finally, dynamic time history response features of a damped SDOF system subjected to pulse excitations are examined. These special aspects of pulse waveforms and their response spectra should be taken into account in the estimation of ground motions for a project site close to a fault. 相似文献
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为了评价4种等效线性场地响应软件的适用性,选取深厚场地作为研究对象,将基岩地震波作为地震输入,根据土层剪切波波速和容重确定初始剪切模量并设置对应的模量衰减和阻尼比曲线,分别用SHAKE 2000、 DEEPSOIL、EERA和Strata 4种等效线性场地响应程序计算得到地表的加速度时程及相应的加速度反应谱和傅里叶幅值谱\,场地的最大剪应变和峰值加速度随深度的变化曲线。计算结果表明,由4种场地响应软件得到的地表加速度时程对应的加速度反应谱和傅里叶幅值谱一致,由于土层划分方式不同,Strata软件得到的峰值加速度和最大剪应变深度曲线不同。总结4种软件的不同,DEEPSOIL可以较全面考虑土的动力特性,Strata提供随机振动理论进行场地响应分析并可以考虑土层参数的变异性。 相似文献
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The nonlinear response of structures is usually evaluated by considering two accelerograms acting simultaneously along the orthogonal directions. In this study, the infl uence of the earthquake direction on the seismic response of building structures is examined. Three multi-story RC buildings, representing a very common structural typology in Italy, are used as case studies for the evaluation. They are, respectively, a rectangular plan shape, an L plan shape and a rectangular plan shape with courtyard buildings. Nonlinear static and dynamic analyses are performed by considering different seismic levels, characterized by peak ground acceleration on stiff soil equal to 0.35 g, 0.25 g and 0.15 g. Nonlinear dynamic analyses are carried out by considering twelve different earthquake directions, and rotating the direction of both the orthogonal components by 30° for each analysis(from 0° to 330°). The survey is carried out on the L plan shape structure. The results show that the angle of the seismic input motion signifi cantly infl uences the response of RC structures; the critical seismic angle, i.e., the incidence angle that produces the maximum demand, provides an increase of up to 37% in terms of both roof displacements and plastic hinge rotations. 相似文献
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Decoupled seismic analysis of an earth dam 总被引：2，自引：0，他引：2
The seismic stability of an earth dam is evaluated via the decoupled displacement analysis using the accelerograms obtained by ground response analysis to compute the earthquake-induced displacements. The response analysis of the dam is carried out under both 1D and 2D conditions, incorporating the non-linear soil behaviour through the equivalent linear method. Ten artificial and five real accelerograms were used as input motions and four different depths were assumed for the bedrock.1D and 2D response analyses were in a fair agreement with the exception of the top third of the dam where only a 2D modelling of the problem could ensure that the acceleration field is properly described. The acceleration amplification ratio obtained in the 2D analyses was equal to about 2 in all the cases considered, consistently with data from real case histories.The maximum permanent displacements computed by the sliding block analysis were small, being less than 10% of the service freeboard; a satisfactory performance of the dam can then be envisaged for any of the seismic scenarios considered in the analyses. 相似文献
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设计反应谱长周期区段的研究 总被引：24，自引：7，他引：17
本文利用近20年国内外大地震时获得的数字强震仪记录分析强震动的长周期分量特性,给出了不同场地上的平均加速度反应谱及其拟合曲线。结果表明,现行抗震设计规范中设计谱的特征周期和长周期谱值明显偏小。在此基础上提出了长周期设计反应谱的修正建议。文中还根据统计分析提出了不同阻尼比的反应谱修正公式。 相似文献
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利用基于动力学拐角频率的随机有限断层法,针对2013年3月29日和8月30日乌鲁木齐发生的MS5.6和MS5.1两次地震,选择不同机构的震源参数对23个台站的45条强震记录进行强地震动模拟,对比分析加速度时程和反应谱,并计算模型偏差.通过与实际场点记录进行对比的结果显示:选取的不同机构震源参数模型得到的模拟加速度时程在持时和形状上与实际记录有一定差距,对于近震源的台站,模拟结果的峰值加速度(PGA)比观测结果小,对于稍远的台站,结果基本能够保持一致;而加速度反应谱,模拟结果与观测结果具有较好一致性; 随机有限断层模型的误差在±0.5以内,拟合效果较好,而且高频段的拟合效果要好于低频段;采用不同机构震源参数模型得到的模拟结果与观测结果得到的PGA分布特征较为一致,但模拟结果的峰值加速度要低于观测结果. 相似文献
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以巨-子结构抗震体系、隔震体系以及智能隔震体系为研究对象,选择4组具有速度脉冲特性的实际地震动加速度记录及人工模拟的具有相同加速度反应谱而无速度脉冲的地震动时程分别作为地震动输入,采用数值分析方法分别计算在有、无速度脉冲的地震动激励下三种结构体系的地震响应,探讨地震动的速度脉冲对巨型结构体系在不同控制策略下地震响应的影响。研究结果表明:三种结构体系在速度脉冲型地震动作用下的地震响应大部分要大于无速度脉冲型的地震响应,近断层地震动的速度脉冲对巨-子结构抗震体系、隔震体系以及智能隔震体系的地震响应均有一定的不利影响。智能隔震体系对速度脉冲地震动较为敏感,但能有效地减小隔震层位移。 相似文献
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A study of floor response spectra for a base-isolated multi-storey structure under sinusoidal and seismic ground excitations is carried out. Several base isolation systems including the laminated rubber bearing, the pure-friction, the resilient-friction, the Électricité de France and the sliding resilient-friction systems are considered. A sinusoidal ground acceleration and several earthquake accelerograms (including those of El Centro 1940, Pacoima Dam 1971 and Mexico City 1985) are used to evaluate the floor response spectra. The characteristics of the spectra generated by different base isolation systems are studied, and the results are compared with those for the fixed-base structure. It is shown that the structural contents can be protected against earthquakes by the use of properly designed base isolation systems. In particular, the laminated rubber bearing system appears to be remarkably effective in protecting the secondary systems under a variety of conditions. 相似文献
13.
P. Triantafyllidis P. Suhadolc P. M. Hatzidimitriou A. Anastasiadis N. Theodulidis 《Pure and Applied Geophysics》2004,161(5-6):1185-1203
— We estimate the theoretical site response along seven cross sections located in the city of Thessaloniki (Greece). For this purpose the 2-D structural models used are based on the known geometry and the dynamic soil properties derived from borehole measurements and other geophysical techniques. Several double-couple sources have been employed to generate the seismic wavefield, and a hybrid method that combines the modal summation with finite differences, has been deployed to produce synthetic accelerograms to a maximum frequency of 6 Hz for all components of motion. The ratios between the response spectra of signals derived for the 2-D local model and the corresponding spectra of signals derived for the 1-D bedrock reference model at the same site, allow us to estimate the site response due to lateral heterogeneities. We interpret the results in terms of both geological and geometrical features of the models and of the characteristics of the wave propagation. The cases discussed confirm that the geometry and depth of the rock basement, along with the impedance contrast, are responsible for ground amplification phenomena such as edge effects and generation and entrapment of local surface waves. Our analysis also confirms that the peak ground acceleration is not well correlated with damage and that a substantially better estimator for possible damage is the spectral amplification. 相似文献
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Linear Amplification of Horizontal Strong Ground Motion in Zagreb (Croatia) for a Realistic Range of Scaled Point Sources 总被引：2，自引：0，他引：2
Marijan Herak Ivan Lokmer Franco Vaccari Giuliano F. Panza 《Pure and Applied Geophysics》2004,161(5-6):1021-1040
— The linear amplification of the larger horizontal component of strong ground motion along a selected profile in the city of Zagreb is estimated by examining the synthetic waveforms corresponding to a suite of 16 realistically chosen scaled point sources. The accelerograms, computed for the average bedrock model by modal summation, are propagated through local laterally heterogeneous anelastic models by the finite-difference algorithm. The ratio of peak ground acceleration (PGA) and of the response spectra (RS), obtained by using local and bedrock models, define the PGA and RS amplification AMP(PGA) and AMP(RS), respectively. Even variations of the order of commonly observed uncertainties of only dip and rake angles of the causative fault show that both AMP(PGA) and AMP(RS) vary at some sites by more than a factor of two. It follows that, especially for strongly laterally heterogeneous structures, local effects must be determined for each of the relevant sources considering all associated uncertainties as completely as possible. Such a conclusion certainly holds for the case of the microzonation of Zagreb, where the local geology is quite complex, and the seismicity is not confined to a single seismic source zone. 相似文献
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以安徽省滁州市地震小区划场地为研究对象,基于ABAQUS显式有限元并行计算平台,采用大尺度二维精细化有限元非线性分析方法,研究了局部地质条件差异对场地地震效应的影响。结果表明：该场地地震动放大效应明显,河漫滩地表PGA放大效应尤为显著;相比一级阶地,河漫滩地表加速度反应谱谱形加宽,谱峰向长周期方向移动,移动幅度约为0．05～0．25S,相应的特征周期增大。地表加速度反应谱呈双峰甚至多峰特征,大尺度场地非线性有限元分析能定性反映出局部地质条件对场地地震效应特性的影响,可为城市地震小区划提供更为合理的科学依据。 相似文献
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沈阳2×200兆瓦低温核供热站厂址基准地面运动参数的确定 总被引：2，自引：0，他引：2
本文在综合厂址、近区域及区域地震地质资料的基础上,根据有关规范的要求,采用地震构造法、最大历史地震法和概率法分别计算了沈阳2×200兆瓦低温核供热站厂址的极限安全地震动SL-2,计算结果分别为200Gal、125Gal和170Gal。取三者最大值,厂址SL-2应当是200gal。厂址基岩地面运动SL-2水平向加速度反应谱取确定性法和概率法计算曲线的外包线作为用于厂址的基岩加速度反应谱。 相似文献
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The modeling of seismic load is a major topic that has to be addressed thoroughly in the framework of performance based seismic analysis and design. In this paper, a simple procedure for simulating artificial earthquake accelerograms matching the statistical distribution of response spectra, as given by median ground motion prediction equations, the standard deviation and correlation coefficients, is proposed. The approach follows the general ideas of the (natural) ground motion selection algorithms proposed by Baker [4] and Wang [43] but using simulated (artificial) “spectrum-compatible” accelerograms. This allows to simulate spectrum-compatible accelerograms featuring variability similar to the one of recorded accelerograms when the match of median and ±1 standard-deviation response spectra is imposed by the regulator. The procedure is illustrated by an application to the NGA ground motion data and models. 相似文献
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The rocking response of large flexible structures to earthquakes 总被引：1，自引：0，他引：1
The rocking response of structures subjected to strong ground motions is a problem of ‘several scales’. While small structures are sensitive to acceleration pulses acting successively, large structures are more significantly affected by coherent low frequency components of ground motion. As a result, the rocking response of large structures is more stable and orderly, allowing effective isolation from the ground without imminent danger of overturning. This paper aims to characterize and predict the maximum rocking response of large and flexible structures to earthquakes using an idealized structural model. To achieve this, the maximum rocking demand caused by different earthquake records was evaluated using several ground motion intensity measures. Pulse-type records which typically have high peak ground velocity and lower frequency content caused large rocking amplitudes, whereas non-pulse type records caused random rocking motion confined to small rocking amplitudes. Coherent velocity pulses were therefore identified as the primary cause of significant rocking motion. Using a suite of pulse-type ground motions, it was observed that idealized wavelets fitted to velocity pulses can adequately describe the rocking response of large structures. Further, a parametric analysis demonstrates that pulse shape parameters affect the maximum rocking response significantly. Based on these two findings, a probabilistic analysis method is proposed for estimating the maximum rocking demand to pulse-type earthquakes. The dimensionless demand maps, produced using these methods, have predictive power in the near-field provided that pulse period and amplitude can be estimated a priori. Use of this method within a probabilistic seismic demand analysis framework is briefly discussed. 相似文献
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In this paper, the method presented by Lee and Trifunac (1985) for generating synthetic torsional accelerograms has been extended to the estimation of synthetic rocking accelerograms and of their response spectra. Results from our previous regression analyses for the characterization of strong shaking in terms of (1) earthquake magnitude and epicentral distance, or (2) Modified Mercalli Intensity at the site are utilized here again. The effects of geologic environment, in terms of site parameters or the representative depth of sediments, which influence amplification, and the dispersive properties of ground motion are also included. The synthetic rocking accelerogram is then constructed from the horizontal and vertical acceleration components. 相似文献
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Identification of acceleration pulses in near-fault ground motion using the EMD method 总被引：2，自引：0，他引：2
In this paper, response spectral characteristics of one-, two-, and three-lobe sinusoidal acceleration pulses are investigated, and some of their basic properties are derived. Furthermore, the empirical mode decomposition （EMD） method is utilized as an adaptive filter to decompose the near-fault pulse-like ground motions, which were recorded during the September 20, 1999, Chi-Chi earthquake. These ground motions contain distinct velocity pulses, and were decomposed into high-frequency （HF） and low-frequency （LF） components, from which the corresponding HF acceleration pulse （if existing） and LF acceleration pulse could be easily identified and detected. Finally, the identified acceleration pulses are modeled by simplified sinusoidal approximations, whose dynamic behaviors are compared to those of the original acceleration pulses as well as to those of the original HF and LF acceleration components in the context of elastic response spectra. It was demonstrated that it is just the acceleration pulses contained in the near-fault pulse-like ground motion that fundamentally dominate the special impulsive dynamic behaviors of such motion in an engineering sense. The motion thus has a greater potential to cause severe damage than the far-field ground motions, i.e. they impose high base shear demands on engineering structures as well as placing very high deformation demands on long-period structures. 相似文献