共查询到19条相似文献，搜索用时 93 毫秒
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利用关东盆地及其周边KiK-net台网井上台站记录的2004—2017年15次中强地震（矩震级为5.1～6.9级）构建三分量记录显著持时Ds5-95数据库。针对该数据库,基于残差分析方法和3种水平向地震动持时参数预测方程,计算并给出事件间残差和事件内残差及其随不同类别参数的变化。在此基础上,初步探讨了水平向地震动持时预测方程应用于预测竖向地震动持时的可行性及盆地对三分量地震动持时的影响。研究结果表明,对于震源距和场地VS30相当的情况,盆地内台站持时普遍大于盆地外台站持时,盆地内、外台站竖向地震动持时均大于水平向地震动持时;3种预测方程均可实现对盆地外台站水平向地震动Ds5-95的合理估计,但在一定程度上低估了盆地内台站的水平向地震动Ds5-95;3种预测方程均无法直接应用于竖向地震动持时预测。 相似文献
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强震动记录的使用通常不考虑观测方向对于水平地震动参数计算的影响。文中以2008年汶川Ms8.0级地震中绵竹清平台获取的强震动记录为研究对象,对记录进行水平向旋转以模拟观测方向的变化,分析水平向峰值加速度PGA、峰值速度PGV、相对持时DR、绝对持时DA及谱加速度PSA随观测方向的变化情况。结果表明,PGA、PGV及PSA的计算较大依赖于观测方向,而DR和DA则受观测方向影响较小。为此文中提出了一种与观测方向无关的水平地震动参数计算方法,对于计算诸如PGA、PGV等与周期无关的地震动参数时不考虑周期独立;而对于计算诸如PSA等与周期有关的地震动参数时考虑周期独立。 相似文献
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汶川地震中强震持时的特征研究 总被引：1，自引：0，他引：1
基于汶川地震断层距150 km内56个台站三分量加速度记录分析地震动重要持时的特征,并建立了持时与断层距的拟合关系。与已建立的持时公式比较,以往分析结果都大大低估了汶川地震动持时。近断层特征对地震动持时有显著影响。断层距小于30 km,上盘和下盘场点的持时明显低于平均水平;断层距大于30 km,地震动持时受到下盘效应的影响,持时较长。破裂方向性效应引起地震动持时在垂直断层方向与水平方向上的差异,同时断层破裂前方向场点的地震动持时较短,比破裂后方向场点的持时小近一倍。 相似文献
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地震动持时作为表征地震动的三要素之一,其对震害的影响逐渐被人们所认识.然而,在地震动持时的定义方面,目前没有统一且明确的概念,文中给出了广义的地震动总持时和强震持时的定义,研究者们根据各自领域的研究特点选择更适合的持时.持时大致可以分为两个大类:一是绝对持时,即基于加速度绝对值阈值的括号持时;二是相对持时,也就是反映地震动过程强度或能量变化趋势的持时,比如能量控制的相对持时等.持时的定义有很多种,文章简单地回顾了地震动持时的五种定义,同时,细致地分析了五种持时定义所表现的特点,并介绍了持时预测模型的研究成果,最后针对目前应用持时存在的问题提出了几点认识. 相似文献
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地震动记录持时与工程持时 总被引：5，自引：0，他引：5
本文将现有地震动持时定义区分为记录持时和反应持时两种,并对其优、缺点进行了评述。文中提出了地震动工程持时的概念和定义,并推导出工程持时的预报方程。工程持时具有概念清晰直观和计算简便的特点,预报方程既与主要地震参数、又与主要结构参数相关联,既能客观地描述地震动的持时特征,又能满意地给出地震动持时对结构地震破坏的影响,同时它的预报方程可以方便地实现与其它持时的预报方程之间的转换,广泛地利用已有的持时预报结果。 相似文献
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简要介绍了2011年3月24日缅甸勐帕亚M7.2地震发生后,云南强震动台网中心55个台站接收到的强震动记录及其初步处理结果,并对地震动衰减关系拟合、频谱随震中距的震域变化及地震动持时特征进行了分析.结果表明:由云南地区强震动记录资料拟合的地震动衰减关系相对于大陆区域的地震动衰减关系,与此次强震动记录具有更好的相关性.地震动加速度卓越频率依Ⅰ、Ⅱ、Ⅲ类场地及楼房结构而依次变低,且随着震中距加大,强震动记录主频值呈变小趋势.场地类别对地震动水平分量持时的影响比竖向分量更明显一些.最后对仪器触发范围、方式、响应半径问题进行了探讨. 相似文献
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地震动持时对结构低周疲劳、破坏累积效应以及非弹性破坏具有显著影响,合理确定地震动持时至关重要。基于汶川地震记录资料,分析旋转不变平均持时与测点记录持时的大小比值关系和相关性,探讨其随断层距的空间变化规律。结果表明:旋转不变平均持时在数值上不恒等于测点记录持时、两水平分量持时的算术平均值及矢量和时程持时的任一量。旋转不变平均能量持时和相对Bolt持时将随断层距的增大而增加,旋转不变平均绝对Bolt持时则将随断层距的增大而减小。旋转不变平均持时与测点记录持时具有强相关性;相比较而言,90%能量持时的相关性强于70%能量持时;绝对Bolt持时的相关性强于相对Bolt持时;能量持时的相关性强于Bolt持时。 相似文献
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2008年汶川地震中江油市太白公园曲径桥上的石雕发生转动破坏现象,本文对这一转动现象进行了振动台模拟试验。模拟试验结果表明:① 在振动台三向加载1.5倍的汶川地震江油台记录的平动加速度后,模型的转动情况与实际观测的石雕转动情况比较一致;② 石雕的转动与石雕的非对称性、地震动输入角度和地震动的竖向作用有关;③ 加载竖向地震动作用后,石雕模型会发生摇摆现象,说明竖向地震动是造成模型扭转现象的重要原因,这也说明在分析相似震害现象时竖向地震动作用不可忽视。 相似文献
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ANALYSIS ON THE CHARACTERISTICS OF DURATION AND PERIOD OF GROUND MOTION OF THE LUSHAN EARTHQUAKE BASED ON THE STATION RECORDS 
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下载免费PDF全文 Based on 60 records from the 20 stations within 100km to the epicenter of Lushan earthquake, the predominant period, period of peak response spectrum, duration of ground motion, and source duration are investigated. By the study, we conclude that within 100km to the epicenter, the scope of predominant period is 0.013~0. 275s in EW, NS and UD direction; the scope of period of peak response spectrum for 5% damping ratio is 0.03~0.65s; the scope of 90% ground motion durations is 5. 1~35. 9s; the scope of averaging source duration is 6.41 (EW), 6.05 (NS) and 5.47s (UD). Furthermore, based on the ground motion duration calculated by 20 stations dada, the predictive curve and equation of ground motion duration is regressed and compared with the recent equation of ground motion duration by Bommer (2009). We find that the ground motion durations of most stations are larger than predictively mean value by Bommer (2009), which means that the source effect of Lushan earthquake is relatively larger. Lastly, by the contour figure of ground motion duration and source duration, we conclude that the directivity character of duration is relatively apparent in NE direction. The relatively larger source duration and ground motion duration in NE direction indicate more energy release in the main shock of Lushan earthquake, which perhaps causes the relatively less aftershocks in this direction. The duration has no hanging wall effect, which perhaps results from the blind-reverse fault structure of Lushan earthquake. 相似文献
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Strong motion duration is one of the challenging characteristics of ground motion, which affects the cumulative damage of structures significantly. Many researchers have conducted investigations related to the effects of strong motion duration on the response of building structures. However, the corresponding studies of concrete gravity dams are limited. In this paper, the effects of strong motion duration on the accumulated damage of concrete gravity dams are investigated. A Concrete Damaged Plasticity (CDP) model including the strain hardening or softening behavior is selected for the concrete material. This model is used to evaluate the nonlinear dynamic response and seismic damage process of Koyna dam during 1976 Koyna earthquake. Subsequently, the damage analyses of Koyna dam subjected to earthquake motions with different strong motion durations are performed. 20 as-recorded accelerograms, which are modified to match a 5% damped target spectrum, are considered in this study. Strong motion durations are obtained based on the definition of significant duration. According to the characteristics of the cracking damage development, both local and global damage indices are established as the response parameters. The results show that strong motion duration is positively correlated to the accumulated damage for events with similar response spectrum, and has significant influence on the cumulative damage of the dam. Longer duration will lead to greater accumulation damage to which aseismic design of the dam should be given attention. 相似文献
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Preliminary analysis of the hanging wall effect and velocity pulse of the 5.12 Wenchuan earthquake 总被引：3，自引：2，他引：1
A preliminary study of the PGA attenuation, hanging wall effect and velocity pulse characteristics from the 2008 Wenchuan earthquake of Ms =8.0 is described in this paper. The study was carried out through analyses in the time and frequency domains of main earthquake records. In the PGA attenuation study, records from 316 stations less than 1000 km from the surface rupture of the fault were used as a database and attenuation relationships were developed and compared with some existing relationships that are widely used in mainland China, Chinese Taiwan and the US. At the same time, records from 28 stations less than 100 km from the fault were used to study the hanging wall effect and velocity pulse characteristics of this earthquake based on the distribution of PGA, PGV, spectral acceleration, and the velocity pulse peak, and the results are compared with the 1999 Chi-Chi earthquake. In addition, the large PGAs of the UD components observed in this event are also discussed in this paper. From the results of the preliminary study, some conclusions are developed and suggestions for further research are proposed. 相似文献
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Strong motion duration affects the cumulative damage of structures significantly. There are more than 30 different definitions of strong motion duration. This study describes numerically, the interdependency between several different definitions of strong motion duration and structural accumulated damage indices, and the aim is to determine the definitions of strong motion duration that exhibit the strongest influence on structural damages. For this purpose, 20 as-recorded accelerograms with a wide range of durations, which are modified to match a 5% damped target spectrum, are considered in this study, and several different definitions of strong motion duration, such as significant duration, bracketed duration and uniform duration are proposed for measuring these durations. On the other hand, nonlinear seismic analyses of concrete gravity dams subjected to earthquake motions with different strong motion durations are conducted according to the Concrete Damaged Plasticity (CDP) model including the strain hardening or softening behavior. Peak displacement, local damage index, global damage index and damage energy dissipation are established for characterizing the influence of strong motion duration on the dynamic response of concrete gravity dams. The degree of the interrelationship between strong motion durations and damage measures is provided by correlation coefficients. Comparison of the correlation between the different durations of the ground motion and different damage measures reveals that strong motion durations calculated from different definitions have no significant influence on damage measure based on the peak displacement response of the dam, but are positively correlated to the accumulated damage measures such as the local damage index, global damage index and damage energy dissipation for events with similar response spectrum. 相似文献
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2008年汶川MS8.0地震中, 固定和流动地形影响台阵记录到大量主余震记录, 本文通过对其均方根加速度、 相对持时、 频谱等要素进行分析, 讨论了山体地形效应的特征及其影响因素. 对于自贡西山公园地形台阵各测点的分析结果显示: 该台阵山脚基岩位置地震动的均方根加速度和相对持时明显低于山体周边土层场地和山体基岩测点; 随着高程的增加, 山体基岩测点的均方根加速度逐渐变大, 相对持时则变化不大, 傅里叶谱形状也大体一致, 在2.0—5.0 Hz频段内有所放大; 山体周边土层场地和山体地形对于相同地震动输入中不同频段内地震动能量的放大水平不同, 从而导致二者的地表地震动强度产生显著差异, 且前者对地震动持时的增加更加显著. 相似文献
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Multiple regression analyses of the duration of earthquake ground acceleration are presented. Two types of duration are considered, i.e. bracketed duration and normalized duration. The bracketed duration ta is defined as the elapsed time between the first and last acceleration excursions greater than a [cm/s2], and the normalized duration Tα is defined as the elapsed time between the first and last acceleration excursions greater than α times (0 < α < 1) the peak acceleration. Employed are 394 components of horizontal strong motion acceleration records obtained at 67 free field sites in Japan. With the use of multiple regression analysis, the dependence of the bracketed and normalized durations on earthquake magnitude and epicentral distance is studied. 相似文献
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近断层地震动中存在的低频、大幅值速度脉冲使得临近断层结构具有更高的强度和延性需求。对近断层地震动脉冲特性的深入研究有利于加深对临近断层结构反应的认识,从而为临近断层结构抗震设计提供理论依据。受强震记录处理及速度脉冲识别和提取方法的限制,目前已有的研究工作主要集中于近断层地震动记录的单脉冲特性,多脉冲特性涉及较少。本文基于希尔伯特-黄变换及其相关理论,针对近断层地震动,提出了涵盖原始强震记录基线校正,至多速度脉冲定量判别及提取的整套脉冲特性研究方法,该方法对多脉冲记录尤为有效;基于提取出的理想化速度脉冲构建了（多）脉冲参数与地震参数的统计关系;以脉冲持时新定义了近断层地震动的有效强震持时,并通过多层结构非线性时程分析进行了验证。新方法中,基线校正过程可以获得稳定的地面峰值位移（PGD）和具有物理意义的基线偏移时程;提出的速度脉冲识别及波形提取方法可以将每个脉冲准确定位于时域,同时自动化获得脉冲相关参数;基于理想脉冲定义的近断层地震动有效强震持时可以良好地 表征多脉冲记录的强度。 相似文献