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竖向地震动加速度反应谱特性 总被引：3，自引：0，他引：3
以33次地震中的地表地震动记录为数据基础,考虑场地条件、震级和距离的影响,分别对竖向地震动的加速度规准化反应谱和双规准化反应谱进行了研究。结果表明,规准反应谱明显受到场地条件、震级和震中距的影响,不同场地、距离和震级的平均规准反应谱之间差别显著;相比较而言,不依赖于场地、距离和震级的平均双规准反应谱之间却表现出良好的规律性和一致性。双规准反应谱的统一特性可以为竖向地震动设计谱的预测提供参考依据。 相似文献
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To develop uniform and seismic environment-dependent design spectrum, common acceleration response spectral characteristics need to be identified. In this paper, a bi-normalized response spectrum (BNRS) is proposed, which is defined as a spectrum of peak response acceleration normalized with respect to peak acceleration of the excitation plotted vs. the natural period of the system normalized with respect to the spectrum predominant period, Tp. Based on a statistical analysis of records from the 1999 Chi-Chi earthquake, the conventionally normalized response spectrum(NRS) and the BNRS are examined to account for the effects of soil conditions, epicentral distance, hanging wall and damping. It is found that compared to the NRS, the BNRS is much less dependent on these factors. Finally, some simple relationships between the BNRS for a specified damping ratio and that for a damping ratio of 5%, and between the spectra predominant period and epicentral distance for different soil types are provided. 相似文献
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本文在统计了大量强震记录的基础上,分别研究了双规准加速度反应谱和双规准速度反应谱的特性,进行了对比分析,并分别得出了定量分析的结果。研究结果表明,双规准加速度反应谱在短周期段有很好的统一性,而双规准速度反应谱在长周期段的统一性较好,这种规律性对于认识地震动的特性、改进抗震设计反应谱具有重要的意义。 相似文献
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双规准化地震动加速度反应谱研究 总被引：3，自引：3，他引：0
本文提出了双规准反应谱的概念。在统计了美国西部大量强震记录的基础上,分别研究了规准反应谱和双规准反应谱的特性,并进行了详细的对比分析。研究结果表明,双规准反应谱比通常的规准反应谱有更好的规律性,这不仅有利于认识地震动的特性,还可使基于场地的抗震设计反应谱大大简化,更便于广大工程设计人员应用。 相似文献
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This paper presents a methodology for constructing seismic design spectra in near-fault regions.By analyzing the characteristics of near-fault pulse-type ground motions,an equivalent pulse model is proposed,which can well represent the characteristics of the near-fault forward-directivity and fling-step pulse-type ground motions.The normalized horizontal seismic design spectra for near-fault regions are presented using recorded near-fault pulse-type ground motions and equivalent pulse-type ground motions,which are derived based on the equivalent pulse model coupled with ground motion parameter attenuation relations.The normalized vertical seismic design spectra for near-fault regions are obtained by scaling the corresponding horizontal spectra with the vertical-to-horizontal acceleration spectral ratios of near-fault pulse-type ground motions.The proposed seismic design spectra appear to have relatively small dispersion in a statistical sense.The seismic design spectra for both horizontal and vertical directions can provide alternative spectral shapes for seismic design codes. 相似文献
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Modern seismic design allows a structure to develop inelastic response during moderate to severe earthquakes. The emerging performance-based design requires more clearly defined levels of inelastic response, or damage, to be targeted for different earthquake hazard levels. While there are a range of factors that could influence the level of damage and hence the performance, the design strength remains to be a fundamental design parameter that is inherently related to the structural performance. In this paper, the response reduction factor, which is a normalized form of the design strength, is investigated on a direct damage basis. The implications of the damage-based strength reduction factor (SRF), denoted as RD factor, on multiple performance targets are discussed. A series of RD spectra are generated from a large set of ground motions in different groupings to examine the effects of local site condition, earthquake magnitude and distance to rupture on the RD spectra. The overall mean and standard deviation of the RD spectra for different levels of damage are obtained, and simple empirical formulas are proposed. 相似文献
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In this paper, ground motion during six past devastating earthquakes and one possible future event in the northeastern part
of India is estimated by seismological approaches. Considering uncertainty in the input source parameters, a series of ground
motions have been simulated. The peak ground acceleration (PGA) and response spectra at important cities and towns in the
epicentral regions of these events are obtained. The PGA distribution over the entire northeastern region of India, encompassing
the epicenter, is presented in the form of contours. The obtained results can be used for the seismic analysis and design
of structures in this region. 相似文献
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—?The mapping of the seismic ground motion in Bucharest, due to the strong Vrancea earthquakes, is carried out using a complex hybrid waveform modeling method that allows easy parametric tests. Starting from the actually available strong motion database, we can make realistic predictions for the possible ground motion. The basic information necessary for the modeling consists of: (a) The representative mechanisms for the strong subcrustal events, (b) the average regional structural model, and (c) the local structure for Bucharest. Two scenario earthquakes are considered and the source influence on the local response is analyzed in order to define generally valid ground motion parameters, to be used in the seismic hazard estimations. The source has its own (detectable) contribution on the ground motion and its effects on the local response in Bucharest are quite stable on the transversal component (T), while the radial (R) and vertical (V) components are sensitive to the scenario earthquake. Although the strongest local effects affect the T component, both observed and synthetic, a complete determination of the seismic input for the built environment requires the knowledge of all three components of motion (R, V, T). The damage observed in Bucharest for the March 4, 1977 Vrancea event, the strongest earthquake to strike the city in modern times, is in agreement with the synthetic signals and local response. 相似文献
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Andrei Bala Bogdan Grecu Viorica Ciugudean Victor Raileanu 《Soil Dynamics and Earthquake Engineering》2009
Bucharest is one of the cities most affected by earthquakes in Europe. Situated at 150–170 km distance from Vrancea epicentral zone, Bucharest had suffered many damages due to high energy Vrancea intermediate-depth earthquakes. For example, the 4 March 1977 event produced the collapse of 32 buildings with 8–12 levels, while more than 150 old buildings with 6–9 levels were seriously damaged. The studies done after this earthquake had shown the importance of the surface geological structure upon ground motion parameters. New seismic measurements are performed in Bucharest area aiming at defining better elastic and dynamic properties of the shallow sedimentary rocks. Down-hole seismic measurements were performed in a number of 10 cased boreholes drilled in the Bucharest City area. Processing and interpretation of the data lead to the conclusion that shallow sedimentary rocks can be considered weak in the area, down to 150–200 m depth. Seismic wave velocity values and bulk density values presented in the paper associated with local geology are useful primary data in the seismic microzonation of Bucharest City. They are used as 1D models to derive transfer functions and response spectra for the stack of sedimentary rocks in several parts of Bucharest area, leading to a better knowledge of the local site amplification and associated frequency spectra. In a recent study the H/V spectral ratio using Nakamura’s method was applied on the seismic noise measurements in 22 sites in Bucharest City in order to derive the fundamental period associated with these sites. The values confirm the previous results, showing a dominant resonance in the period range of 1.25–1.75 s. The fundamental periods obtained with Nakamura’s method are in good agreement with those computed on the basis of geological and geotechnical data in boreholes, which show an increase of the fundamental period in the Bucharest area from south to north, in the same direction as the increase of the thickness of the Quaternary deposits above the Fratesti layer which is considered the bedrock in the area. 相似文献
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Kusnowidjaja Megawati Tso-Chien Pan Kazuki Koketsu 《Soil Dynamics and Earthquake Engineering》2005,25(1):11-25
Singapore and Kuala Lumpur, the capital of Malaysia, may well represent the classic examples of area with low seismic hazard but with high consequence. Both cities are located in a low-seismicity region of Southeast Asia, where active seismic sources are located more than 300 km away. Seismic designs have not been implemented in this seemingly low-hazard region though distant earthquakes in Sumatra had frequently shaken high-rise structures in the two cities. Several studies have been conducted to systematically assess the seismic hazards of Singapore and the Malay Peninsula. The present research particularly addresses issues in deriving a new set of attenuation relationships of peak ground acceleration (PGA), peak ground velocity (PGV) and response spectral acceleration (RSA) for the Sumatran-subduction earthquakes. To be relevant for the seismic hazard assessment of the remote metropolises, the derived attenuation relationships cover a long distance range from 150 to 1500 km. The attenuation relationships are derived using synthetic seismograms that account for source and path effects. The uncertainties in rupture parameters, such as stress drop, strike, dip and rake angles, have been defined according to the regional geological and tectonic settings as well as the ruptures of previous earthquakes. The seismic potential of the Sumatran subduction zone are high in the region from 2°N to 5°S as there has been no recurrence of great thrust events since 1861. A large event with Mw greater than 7.8 in this particular subduction zone may be capable of generating destructive ground motions in Singapore and Kuala Lumpur, even at a distance of 700 km. 相似文献
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Intensity measures for probabilistic assessment of non‐structural components acceleration demand 
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下载免费PDF全文 Marco De Biasio Stephane Grange Frederic Dufour Frederic Allain Ilie Petre‐Lazar 《地震工程与结构动力学》2015,44(13):2261-2280
A fundamental issue in the framework of seismic probabilistic risk analysis is the choice of ground motion intensity measures (IMs). Based on the floor response spectrum method, the present contribution focuses on the ability of IMs to predict non‐structural components (NSCs) horizontal acceleration demand. A large panel of IMs is examined and a new IM, namely equipment relative average spectral acceleration (E‐ASAR), is proposed for the purpose of NSCs acceleration demand prediction. The IMs efficiency and sufficiency comparisons are based on (i) the use of a large dataset of recorded earthquake ground motions; (ii) numerical analyses performed on three‐dimensional numerical models, representing actual structural wall and frame buildings; and (iii) systematic statistical analysis of the results. From the comparative study, the herein introduced E‐ASAR shows high efficiency with respect to the estimation of maximum floor response spectra ordinates. Such efficiency is particularly remarkable in the case of structural wall buildings. Besides, the sufficiency and the simple formulation allowing the use of existing ground motion prediction models make the E‐ASAR a promising IMs for seismic probabilistic risk assessment. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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This short article evaluates the stochastic method of ground motion simulation for Bucharest area using both the single-corner frequency model and recently introduced double-corner frequency models. A dedicated Q model is derived using ground motions obtained during the largest Vrancea earthquakes from the past 30 years. The simulated ground motions are tested against the observed data from the Vrancea earthquakes of August 1986 and May 1990. Moreover, the observed data are also compared against simulations obtained using the Q model derived by Oth et al. (2008). Finally, the results of the simulations show that the derived Q model is better suited for larger magnitude events, while the Q model of Oth et al. (2008) provides better results for smaller earthquakes. 相似文献
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C. O. Cioflan B. F. Apostol C. L. Moldoveanu G. F. Panza GH. Marmureanu 《Pure and Applied Geophysics》2004,161(5-6):1149-1164
— The mapping of the seismic ground motion in Bucharest, due to the strong Vrancea earthquakes is carried out using a complex hybrid waveform modeling method which combines the modal summation technique, valid for laterally homogeneous anelastic media, with finite-differences technique, and optimizes the advantages of both methods. For recent earthquakes, it is possible to validate the modeling by comparing the synthetic seismograms with the records. We consider for our computations the frequency range from 0.05 to 1.0 Hz and control the synthetic signals against the accelerograms of the Magurele station, low-pass filtered with a cut-off frequency of 1.0 Hz of the 3 last major strong (Mw > 6) Vrancea earthquakes. Using the hybrid method with a double-couple seismic source approximation, scaled for the source dimensions and relatively simple regional (bedrock) and local structure models, we succeeded in reproducing the recorded ground motion in Bucharest at a satisfactory level for seismic engineering. Extending the modeling to the entire territory of the Bucharest area, we construct a new seismic microzonation map, where five different zones are identified by their characteristic response spectra. 相似文献
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震害资料显示,场地条件对地震动特性以及工程结构破坏程度影响显著。为减少因场地效应而造成的经济损失和社会影响,在进行场地地震反应分析时,需最大限度地减小因场地土层模型参数的不确定性引起的地震动评估偏差,为工程结构地震反应分析选取并生成适当的地震动输入。随着强震动观测技术的逐渐发展,大量可靠的钻井台阵记录为地震过程中场地观测点的动力反应提供了直接数据。以美国加州地区La Cienega钻井台阵强震动观测数据为基础,利用互相关函数,对不同强度地震作用下场地土层的平均剪切波速进行分析,并在此基础上,以Cyclic 1D为模拟平台,建立一维自由场地地震反应有限元分析模型。分析结果表明：通过钻井台阵地震动观测数据识别,得到场地平均剪切波速,能够反映该场地的动力特性,数值模拟计算结果和台阵地震动记录基本吻合,可为数值模型参数选取提供依据。 相似文献
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George D. Hatzigeorgiou 《地震工程与结构动力学》2010,39(11):1239-1258
Damping modification factors (DMF) are used in modern seismic codes to adjust elastic response spectral values corresponding to 5% of viscous damping to other higher or lower damping levels. This paper presents a simple and effective procedure to estimate DMF for single‐degree‐of‐freedom systems. Empirical expressions are proposed for displacement, velocity and acceleration response spectra, where four types of soil conditions, from hard rock to soft soil are considered. This study also examines, for the first time, the influence of artificial earthquakes on DMF. Furthermore, natural near‐fault and far‐fault seismic ground motions are considered where it is testified that the fault distance has no impact on DMF. Finally, it confirms that, in contrast to the considerations of many seismic codes, DMF are strongly dependent on the period of structural vibration while there are significant problems of using the same modification factor to estimate maximum displacement, velocity and seismic forces. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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Near-field strong ground motions are useful for engineering seismology studies and seismic design, but dense observation networks of damaging earthquakes are still rare. In this study, based on the strong-motion data from the M w 6.6 Lushan earthquake, the ground motion parameters in different spatial regions are systematically analyzed, and the contributions from different effects, like the hanging-wall effect, directivity effect, and attenuation effect are separated to the extent possible. Different engineering parameters from the observed ground motions are compared with the local design response spectra and a new attenuation relation of Western China. General results indicate that the high frequency ground motion, like the peak ground acceleration, on two sides of the fault plane is sensitive to the hanging-wall effect, whereas the low frequency ground motion, like the long period spectral acceleration, in the rupture propagation direction is affected by the directivity effect. Moreover, although the M w 6.6 Lushan earthquake is not a large magnitude event, the spatial difference of ground motion is still obvious; thus, for a thrust faulting earthquake, in addition to the hanging effect, the directivity effect should also be considered. 相似文献
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The regularities in the radiation and propagation of seismic waves within the Baikal Rift Zone in Buryatia are studied to estimate the ground motion parameters from the probable future strong earthquakes. The regional parameters of seismic radiation and propagation are estimated by the stochastic simulation (which provides the closest agreement between the calculations and observations) of the acceleration time histories of the earthquakes recorded by the Ulan-Ude seismic station. The acceleration time histories of the strongest earthquakes (M W ~ 3.4–4.8) that occurred in 2006–2011 at the epicentral distances of ~96–125 km and had source depths of ~8–12 km have been modeled. The calculations are conducted with estimates of the Q-factor which were previously obtained for the region. The frequency-dependent attenuation and geometrical spreading are estimated from the data on the deep structure of the crust and upper mantle (velocity sections) in the Ulan-Ude region, and the parameters determining the wave forms and duration of acceleration time histories are found by fitting. These parameters fairly well describe all the considered earthquakes. The Ulan-Ude station can be considered as the reference bedrock station with minimum local effects. The obtained estimates for the parameters of seismic radiation and propagation can be used for forecasting the ground motion from the future strong earthquakes and for constructing the seismic zoning maps for Buryatia. 相似文献