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1.
土体剪切波速是进行土层地震反应分析的动力学参数，对场地地震动参数确定具有重要意义。基于地质地貌分析，将大同盆地划分为5类典型地质单元。对盆地1429个钻孔剪切波速资料进行分析，探讨VS30与VS20的相关性，研究土体埋深、岩性、地质单元、标贯击数及密实度等地质特征对VS的影响，并基于地质单元、剪切波速比、密实度系数及第四系上部覆盖层厚度相关性分析给出土体VS30预测模型。研究结果表明，基于典型地质特征的VS30预测模型拟合优度R2>0.90，预测精度很高，对于离散性较大、直接拟合估算较差及无剪切波速场地来说，以区分地质单元及土体类型的方式进行VS30分解预测是良好的研究思路。首次在区分地质单元及土体类型的前提下提出剪切波速比及密实度系数，并将其与第四系上部覆盖层厚度综合应用于VS30预测研究。研究结果可为大同盆地城市防震减灾规划、震害预测、区域性地震安全评价提供重要技术支撑。 相似文献
2.
Gaetano Manfredi 《地震工程与结构动力学》2001,30(4):485-499
In this paper, a method is proposed in order to obtain a simplified representation of hysteretic and input energy spectra. The method is based on the evaluation of the equivalent number of cycles correlated to the earthquake characteristics by the proposed seismic index ID. This procedure allows us to obtain peak values of the hysteretic and input energy that depend on the demanded ductility, on the seismic index ID and on the peak pseudo‐velocity. The assessment of the input energy represents a first step towards the definition of a damage potential index capable of taking into account the effect of the duration of the ground motions. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
3.
The estimation of cyclic deformation demand resulting from earthquake loads is crucial to the core objective of performance‐based design if the damage and residual capacity of the system following a seismic event needs to be evaluated. A simplified procedure to develop the cyclic demand spectrum for use in preliminary seismic evaluation and design is proposed in this paper. The methodology is based on estimating the number of equivalent cycles at a specified ductility. The cyclic demand spectrum is then determined using well‐established relationships between seismic input energy and dissipated hysteretic energy. An interesting feature of the proposed procedure is the incorporation of a design spectrum into the proposed procedure. It is demonstrated that the force–deformation characteristics of the system, the ductility‐based force‐reduction factor Rμ, and the ground motion characteristics play a significant role in the cyclic demand imposed on a structure during severe earthquakes. Current design philosophy which is primarily based on peak response amplitude considers cyclic degradation only in an implicit manner through detailing requirements based on observed experimental testing. Findings from this study indicate that cumulative effects are important for certain structures, classified in this study by the initial fundamental period, and should be incorporated into the design process. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
4.
2019年10月28日甘肃省夏河县发生5.7级地震,中国数字强震动台网的18个专业台站在此次地震中触发。本文处理捕获的54条三分向加速度记录,给出近场台站的地震动参数,绘制了震中附近区域峰值加速度等值线图,其长轴呈WN-ES方向展布。将实际观测数据与几种常用地震动衰减关系对比,发现俞言祥[1]短轴衰减预测模型能更好地反映此次地震的影响场。将振幅较大的62LBL、62BLX台的反应谱与我国抗震设计反应谱比较,采用最小二乘法拟合出不同震中距5个台站各周期谱加速度衰减特性,总结了此次地震的反应谱基本特征。运用H/V谱比法对4个典型台站进行场地地震反应分析,研究了局部场地条件对峰值加速度和峰值速度的影响过程。 相似文献
5.
6.
The theoretical acceleration spectrum of observation site has been obtained from source acceleration spectrum derived from
scaling law, using attenuation modelQ=Q
ν
f
η
. A comparison of a set of theoretical acceleration spectra with observation spectra has been made, and we have obtained the
attenuation model for observation site and seismic moment magnitude. We obtain thatQ
o=300,η=0.25 for Wuqia area, Xinjing Zizhizhou, and seismic moment magnitudes of 18 greater aftershocks of Wuqia earthquake occurred
in 1985. In order to obtain seismic moment magnitued conveniently, three functional tables of acceleration spectra at 1Hz
as the distances for variousQ value have been made. The seismic moment magnitude can be quickly measured from acceleration spectrum at 1Hz according to
these tables (epicenter has to be known).
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,14, 435–445, 1992. 相似文献
7.
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
8.
This paper examines the potential development of a probabilistic design methodology, considering hysteretic energy demand, within the framework of performance‐based seismic design of buildings. This article does not propose specific energy‐based criteria for design guidelines, but explores how such criteria can be treated from a probabilistic design perspective. Uniform hazard spectra for normalized hysteretic energy are constructed to characterize seismic demand at a specific site. These spectra, in combination with an equivalent systems methodology, are used to estimate hysteretic energy demand on real building structures. A design checking equation for a (hypothetical) probabilistic energy‐based performance criterion is developed by accounting for the randomness of the earthquake phenomenon, the uncertainties associated with the equivalent system analysis technique, and with the site soil factor. The developed design checking equation itself is deterministic, and requires no probabilistic analysis for use. The application of the proposed equation is demonstrated by applying it to a trial design of a three‐storey steel moment frame. The design checking equation represents a first step toward the development of a performance‐based seismic design procedure based on energy criterion, and additional works needed to fully implement this are discussed in brief at the end of the paper. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
9.
Displacement response spectrum (DRS), as the input, is of great significance to the displacement-based design just like the acceleration response spectrum to the traditional force-based design. Although the procedure of performance-based, in particular the displacement-based design has achieved considerable development, there is not a general DRS covering an enough long period range for common seismic design yet. This paper develops a systematic ground motion data processing procedure for the purpose of correcting the noise in the earthquake records and generating consistent DRS for seismic design. An adaptive algorithm is proposed to determine the cutoff frequency of the high-pass digital filter. The DRS of more than 500 recorded earthquake ground motions are generated and they are classified into three groups according to the ratio of the peak ground acceleration to the peak ground velocity (A/V) and/or the ratio of the peak ground velocity to the peak ground displacement (V/D). In each group, all the ground motions are normalized with respect to a selected scaling factor. Their corresponding DRS are obtained and then averaged to get the mean and standard deviation DRS, which can be used for both deterministic and probabilistic displacement-based design. 相似文献
10.
The object of this paper is to introduce a procedure for the determination of elastic design earthquake input energy spectra taking into account the influence of magnitude, soil type and distance from the surface projection of the fault. Firstly, an accurate selection of a large set of representative records has been realized. Secondly, the construction of the design input energy spectra has required determining the spectral shapes and a normalization factor which measures seismic hazard in terms of energy. This factor, denoted as the seismic hazard energy factor, has been defined as the area under the earthquake input energy spectrum in the period interval between 0·05 and 4·0 s. Finally, due to the importance of the source-to-site distance in the evaluation of the input energy, an investigation into the attenuation of the seismic hazard energy factor has been carried out. © 1998 John Wiley & Sons, Ltd. 相似文献
11.
2018年9月12日陕西省宁强县发生5.3级地震,中国数字强震动台网的39个专业台站在此次地震中触发。文章中通过处理捕获的117条三分向加速度记录,给出近场台站的地震动参数,绘制震中附近区域峰值加速度等值线图,其长轴呈西南-东北方向展布。采用实际观测数据与几种常用地震动衰减关系对比,发现霍俊荣衰减预测模型能更好地反映此次地震的影响场。将振幅最大的51GYD台的反应谱与我国抗震设计反应谱比较,采用最小二乘法拟合出不同震中距5个台站各周期谱加速度衰减特性,总结出此次地震的反应谱基本特征。运用H/V谱比法对51GYD土层台和62ZM台阵进行局部场地地震反应分析,研究覆盖土层对地震动的放大作用,及局部地形对峰值加速度和峰值速度的影响过程。 相似文献
12.
Y. H. Chai 《地震工程与结构动力学》2005,34(1):83-96
Seismic performance of structures is related to the damage inflicted on the structure by the earthquake, which means that formulation of performance‐based design is inherently coupled with damage assessment of the structure. Although the potential for cumulative damage during a long‐duration earthquake is generally recognized, most design codes do not explicitly take into account the damage potential of such events. In this paper, the classical low‐cycle fatigue model commonly used for seismic damage assessment is cast in a framework suitable for incorporating cumulative damage into seismic design. The model, in conjunction with a seismic input energy spectrum, may be used to establish an energy‐based seismic design. In order to ensure satisfactory performance in a structure, the cyclic plastic strain energy capacity of the structure is designed to be larger than or equal to the portion of seismic input energy contributing to cumulative damage. The resulting design spectrum, which depends on the duration of the ground motion, indicates that the lateral strength of the structure must be increased in order to compensate for the increased damage due to an increased number of inelastic cycles that occur in a long‐duration ground motion. Examples of duration‐dependent inelastic design spectra are developed using parameters currently available for the low‐cycle fatigue model. The resulting spectra are also compared with spectra developed using a different cumulative damage model. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
13.
B. Pace D. Albarello P. Boncio M. Dolce P. Galli P. Messina L. Peruzza F. Sabetta T. San�� F. Visini 《Bulletin of Earthquake Engineering》2011,9(1):199-230
After the April 6th 2009 L’Aquila earthquake (M
w
6.3), where 306 people died and a further 60,000 were displaced, seismic microzoning investigations have been carried out
for towns affected by a macroseismic intensity equal to or greater than 7 MCS. Based upon seismotectonic data, historical
seismicity and strong motion records, we defined input spectra to be used in the numerical simulations of seismic microzoning
in four key municipalities, including the town of L’Aquila. We adopted two main approaches: uniform hazard response spectra
are obtained by a probabilistic seismic hazard assessment introducing some time-dependency for individual faults on the study
area; a deterministic design spectrum is computed from magnitude/distance pairs extracted by a stationary probabilistic analysis
of historical intensities. The uniform hazard spectrum of the present Italian building code represents the third, less restrictive,
response spectrum to be used for the numerical simulations in seismic microzoning. Strong motions recordings of the main shock
of the L’Aquila sequence enlighten the critical role played by both the local response and distances metric for sites located
above a seismogenic fault; however, these time-histories are compatible with the uncertainties of a deterministic utilization
of ground motion predictive equations. As recordings at very near field are rare, they cannot be neglected while defining
the seismic input. Disaggregation on the non-Possonian seismotectonic analysis and on the stationary site-intensity estimates
reach very similar results in magnitude-distance pairs identification; we interpret this convergence as a validation of the
geology-based model by historical observations. 相似文献
14.
Generating ground motion by two new techniques of adding harmonic wave in the time domain and approximating to response spectrum as a whole 总被引：2，自引：0，他引：2
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15.
An energy-based methodology for the assessment of seismic demand 总被引：4，自引：0，他引：4
A methodology for the assessment of the seismic energy demands imposed on structures is proposed. The research was carried out through two consecutive phases. Inelastic design input energy spectra for systems with a prescribed displacement ductility ratio were first developed. The study of the inelastic behavior of energy factors and the evaluation of the response modification in comparison with the elastic case were performed by introducing two new parameters, namely: (1) the Response Modification Factor of the earthquake input energy (RE), representing the ratio of the elastic to inelastic input energy spectral values and (2) the ratio α of the area enclosed by the inelastic input energy spectrum in the range of periods between 0.05 and 4.0 s to the corresponding elastic value. The proposed design inelastic energy spectra, resulting from the study of a large set of strong motion records, were obtained as a function of ductility, soil type, source-to-site distance and magnitude.Subsequently, with reference to single degree of freedom systems, the spectra of the hysteretic to input energy ratio were evaluated, for different soil types and target ductility ratios. These spectra, defined to evaluate the hysteretic energy demand of structures, were described by a piecewise linear idealization that allows to distinguish three distinct regions as a function of the vibration period. In this manner, once the inelastic design input energy spectra were determined, the definition of the energy dissipated by means of inelastic deformations followed directly from the knowledge of hysteretic to input energy ratio.The design spectra of both input energy and hysteretic to input energy ratio were defined considering an elasto-plastic behavior. Nevertheless, other constitutive models were taken into account for comparison purposes. 相似文献
16.
地震动输入能量衰减规律的研究 总被引：6，自引：1，他引：6
对所收集到的266条强震记录，将其按场地条件分类，计算了不同场地条件、不同延性系数下的“绝对”和“相对”输入能量反应谱，然后利用两步回归法，得出了不同场地条件下地震动“绝对”和“相对”两种输入能量的衰减规律，分析了场地条件、延性系数、震级及距离等参数对地震动能量谱的影响，并对两种输入能量衰减规律进行了比较。 相似文献
17.
The use of the shear wave velocity data as a field index for evaluating the liquefaction potential of sands is receiving increased attention because both shear wave velocity and liquefaction resistance are similarly influenced by many of the same factors such as void ratio, state of stress, stress history and geologic age. In this paper, the potential of support vector machine (SVM) based classification approach has been used to assess the liquefaction potential from actual shear wave velocity data. In this approach, an approximate implementation of a structural risk minimization (SRM) induction principle is done, which aims at minimizing a bound on the generalization error of a model rather than minimizing only the mean square error over the data set. Here SVM has been used as a classification tool to predict liquefaction potential of a soil based on shear wave velocity. The dataset consists the information of soil characteristics such as effective vertical stress (σ′v0), soil type, shear wave velocity (Vs) and earthquake parameters such as peak horizontal acceleration (amax) and earthquake magnitude (M). Out of the available 186 datasets, 130 are considered for training and remaining 56 are used for testing the model. The study indicated that SVM can successfully model the complex relationship between seismic parameters, soil parameters and the liquefaction potential. In the model based on soil characteristics, the input parameters used are σ′v0, soil type, Vs, amax and M. In the other model based on shear wave velocity alone uses Vs, amax and M as input parameters. In this paper, it has been demonstrated that Vs alone can be used to predict the liquefaction potential of a soil using a support vector machine model. 相似文献
18.
The aim of this study was to investigate the role of VS30 in site amplifications in the Adapazari region, Turkey. To fulfil this aim, amplifications from VS30 measurements were compared with earthquake data for different soil types in the seismic design codes. The Adapazari area was selected as the study area, and shear-wave velocity distribution was obtained by the multichannel analysis of surface waves (MASWs) method at 100 sites for the top 50 m of soil. Aftershock data following the Mw 7.4 Izmit earthquake of 17 August 1999 gave magnitudes between 4.0 and 5.6 at six stations installed in and around the Adapazari Basin, at Babalı, Şeker, Genç, Hastane, Toyota and Imar. This data was used to estimate site amplifications by the reference-station method. In addition, the fundamental periods of the station sites were estimated by the single station method. Site classifications based on VS30 in the seismic design codes were compared with the fundamental periods and amplification values. It was found that site amplifications (from earthquake data) and relevant spectra (from VS30) are not in good agreement for soils in Adapazari (Turkey). 相似文献
19.
The relationship between Vp and Vs may be used to predict Vs where only Vp is known. Vp/Vs is also used to identify pore fluids from seismic data and amplitude variation with offset analysis. Theoretical, physical, as well as statistical empirical Vp‐Vs relationships have been proposed for reservoir characterization when shear‐wave data are not available. In published work, the focus is primarily on the Vp‐Vs relationship of quartzitic sandstone. In order to broaden the picture we present Vp‐Vs relationships of greensand composed of quartz and glauconite by using data from the Paleocene greensand Nini oil field in the North Sea. A Vp‐Vs relationship derived from modelling is compared with empirical Vp‐Vs regressions from laboratory data as well as from log data. The accuracy of Vs prediction is quantified in terms of root‐mean‐square error. We find that the Vp‐Vs relationship derived from modelling works well for greensand shear‐wave velocity prediction. We model the seismic response of glauconitic greensand by using laboratory data from the Nini field. Our studies here reveal that brine‐saturated glauconitic greensand can have a similar seismic response to that from oil‐saturated quartzitic sandstone and that oil‐saturated strongly cemented greensand can have a similar amplitude variation with offset response to that from brine‐saturated weakly cemented greensand. 相似文献
20.
This paper proposes energy input spectra applicable to seismic design of structures located in low‐to‐moderate‐seismicity regions. These spectra represent the load effect, in terms of input energy, of the most severe earthquake that the construction might encounter during its lifetime. The spectra have been derived through dynamic response analyses of over 100 ground motion records obtained from 48 earthquakes that have occurred in Spain. An empirical equation for estimating the energy input contributable to damage from the total input energy is also suggested. This equation takes into account both the damping and the degree of plastification of the structure. Finally, the proposed design energy input spectra are compared with the provisions of the current Spanish Seismic Code and with the response spectra of recent earthquakes that have occurred in Turkey and Taiwan. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献