共查询到19条相似文献，搜索用时 168 毫秒
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本文详细地分析了用数字化仪和激光扫描仪对模拟加速度记录进行数字化时所产生的误差及消除这些误差的方法，并开发了相关处理软件。数字化误差由数字化设备的系统误差和读数员在操作过程中的随机误差迭加而成，随机数字化误差是具有各态历经性质的、其振幅按高斯规律分布的平稳随机过程。利用激光扫描仪做强震记录数字化，工作效率很高。本文给出了激光扫描仪分析处理软件和消除数字化噪声实例。 相似文献
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本文详细地研究了电流计记录式加速度仪的频率响应失真对强震加速度记录的影响,提出了对失真记录进行校正的两种方法:假想摆法和微分-积分法。计算与实验结果表明:这两种方法都能给出满意的结果,均可推广使用。作为实例,对1976丰11月15日宁河地震(M_L:7.1)的强震加速度记录进行了校正,最大校正量(幅值)达35％。此外,还对比了由失真加速度记录和校正加速度记录计算的位移曲线,表明这种校正工作对获得准确的地震位移曲线是十分必要的。 相似文献
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《地震工程与工程振动》2017,(5)
本文用频域仿真的方法对强震仪加速度记录积分得到位移记录,引入相关系数分析了大位移作用下的强震仪与GPS位移记录的一致性和差异性,结果表明,稳定激发下,两者水平向位移记录的初始相关系数均超过0.8,具有较大的相似度,但仍存在一定的幅值差异,本文主要通过对比分析大位移实验和稳定激发实验来研究该差异性。分析了大位移实验的信噪频谱,大位移实验与稳定激发实验的信号频谱,认为在大位移实验中,强震仪在问题频段的记录很有可能是信号而非噪声。随后,在转角时程中发现,在大转角位移作用下,强震仪和GPS位移记录的差异性表现得更明显,这可能是强震仪受工作原理限制,无法记录到旋转位移所致。随后,本文依据GPS记录的转角信息对强震仪位移进行修正,校正后的位移记录幅值差异明显减小,可以认为由工作原理差异致使参考坐标系的不同是引起两者记录幅值差异的主要原因,同时,也说明GPS能有效的校正强震仪在有转角的复杂观测环境下的位移记录。 相似文献
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介绍了１９９４年９月１６日台湾海峡发生了７．３级强烈地震时，在汕头国际大酒店内的强震加速度记录，这是我国在软弱地基高层建筑结构（２６层）上首次获得的７级以上的强震加速度记录，文中介绍了对记录分析得到的最大加速度（及积分成速度，位移）振动周期等基本结果。 相似文献
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考虑场地特征的强震地面运动参数的统计分析 总被引：4，自引：2，他引：4
本文利用笔者所收集的133条国内外重要强震加速度记录进行统计回归分析,得到反映强震地面运动最大峰值加速度、峰值速度、峰值位移、有效峰值加速度及持续时间衰减规律的回归公式。这些记录中所含七级以上大震、震中距小于20公里的近场记录和基岩上的记录较过去许多研究者用以进行统计的记录要多。统计样本中各类数据的分布比较合理。采用场地等效固有周期(以下简称场地固有周期)取代常用的场地分类形式进行统计,在一定程度上克服了场地分类标准不明确的缺点。场地固有周期依据地质钻探资料计算,从而能比较准确地反映与场地特征有关的强震地而运动衰减规律,为实际工程应用提供可靠的经验公式。 相似文献
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近场数字强震仪记录误差分析与零线校正方法 总被引：6，自引：0，他引：6
本文对数字强震仪记录进行了误差分析,并对国家强震动台网入网的5种型号数字强震仪系统作了振动台对比试验,分析了该系统加速度记录积分后速度和位移时程零线漂移的原因.本文提出了加速度记录的零线漂移校正方法和校正准则.为了印证零线校正方法的可靠性,对振动台试验中强震仪记录到的加速度两次积分得出位移时程与试验时记录到的绝对位移进行比较,计算位移和振动台绝对位移完全一致;对2008年5.12汶川8.0级大地震和1999年台湾9.21集集7.6级地震现场加速度记录两次积分后得出永久位移与两次大地震的GPS同震位移进行比较.结果表明,该方法对大地震近场仪器墩会发生倾斜或产生永久位移时加速度记录的零线校正有明显效果,可以给出加速度积分后的速度和位移并符合校正准则.本文方法解决了对大地震近场地面运动的研究停留在对峰值加速度和反应谱的研究阶段的困惑,满足了结构抗震对地面永久位移的需求. 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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In damage‐based seismic design it is desirable to account for the ability of aftershocks to cause further damage to an already damaged structure due to the main shock. Availability of recorded or simulated aftershock accelerograms is a critical component in the non‐linear time‐history analyses required for this purpose, and simulation of realistic accelerograms is therefore going to be the need of the profession for a long time to come. This paper attempts wavelet‐based simulation of aftershock accelerograms for two scenarios. In the first scenario, recorded main shock and aftershock accelerograms are available along with the pseudo‐spectral acceleration (PSA) spectrum of the anticipated main shock motion, and an accelerogram has been simulated for the anticipated aftershock motion such that it incorporates temporal features of the recorded aftershock accelerogram. In the second scenario, a recorded main shock accelerogram is available along with the PSA spectrum of the anticipated main shock motion and PSA spectrum and strong motion duration of the anticipated aftershock motion. Here, the accelerogram for the anticipated aftershock motion has been simulated assuming that temporal features of the main shock accelerogram are replicated in the aftershock accelerograms at the same site. The proposed algorithms have been illustrated with the help of the main shock and aftershock accelerograms recorded for the 1999 Chi–Chi earthquake. It has been shown that the proposed algorithm for the second scenario leads to useful results even when the main shock and aftershock accelerograms do not share the same temporal features, as long as strong motion duration of the anticipated aftershock motion is properly estimated. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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本文从频域和时域两方面对强震记录的采样和插值过程进行了研究。研究中将采样与插值当作一个信号转换系统,通过数值计算,求得和各种常用的采样和插值过程相对应的传递函数。通过对传递函数的进一步研究表明:采样和插值方式对强震记录数据处理的结果有重要的影响,发现采样过程相当于一个低通滤波器,可以滤除信号中的某些高频信息,而插值过程犹如一个高频噪声源,会在数字记录中引入某些伪高频分量。分析结果还表明:在相同的采样密度下,不等距采样方式具有较高的精度,而等间距采样方式能给出更宽的平坦的频率特性曲线;抛物线插值给出的传递函数结果要比线性插值的结果更精确,这对恢复数字信号中的高频成分具有重要的意义。 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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Roberto Paolucci Antonio Rovelli Ezio Faccioli Carlo Cauzzi Daniela Finazzi Manuela Vanini Carola Di Alessandro Giovanna Calderoni 《地震工程与结构动力学》2008,37(5):697-710
Using records from co‐located broadband and digital strong motion (SM) instruments, it is first shown that the displacement waveforms obtained by double integration of the accelerogram need not be free of unrealistic baseline drift to yield reliable spectral ordinates up to at least 10 s. Secondly, to provide objective criteria for selecting reliable digital SM records for ground motion predictions at long periods, a set of synthetic accelerograms contaminated by random long‐period noise has been used, and the difference between the original accelerograms and the spurious ones in terms of response spectra has been quantified, by introducing a noise index that can be easily calculated based on the velocity waveform of the record. The results of this study suggest that high‐pass filtering the digital acceleration record from a cutoff period selected to suppress baseline drifts on the displacement waveform appears to be in most cases too conservative and unduly depletes reliable information on long‐period spectral ordinates. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
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In this paper a methodology has been presented for constructing the most critical accelerogram from among a be class of candidate accelerograms for a given site and structure. This most critical accelerogram could be used to assess seismic resistance of a structure with a high level of confidence. Specifically, the method superimposes accelerograms recorded at similar sites to create the candidate accelerograms, then uses optimization and approximation techniques find the most critical accelerogram. The most critical accelerogram is defined as the one which maximizes damage is structure, as computed by non-linear dynamic structural analysis, as well as satisfies constraints on ground parameters to ensure credibility. The damage has been defined as cumulative inelastic energy dissipation or sure of interstorey drifts. The method is applied to ten examples in the paper. 相似文献
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时频峰值滤波算法是一种新颖的基于时频分析的信号增强算法,能够有效地消除随机噪声,恢复有效波信息.本文将这种时频分析算法用于消除地震勘探资料中的随机噪声,对淹没于随机噪声下的40道共炮点记录进行时频峰值滤波,恢复出来的共炮点记录可以清楚地表现原始记录同相轴的位置.经过对40道中任选两道（即第21道和第7道）滤波前后的子波形态Wigner\|Ville分布、傅立叶振幅谱等的比较,可知仅在谷值和峰值点误差较大,子波带宽相对误差小于25％.仿真试验表明信噪比可达－7dB,说明该方法可以有效地消减地震资料中的随机噪声. 相似文献
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J. Douglas 《Bulletin of Earthquake Engineering》2003,1(1):141-156
Some accelerograms are affected by non-standard recording and digitization problems that mean they are often not used in strong-motion
studies. These non-standard problems cannot be corrected by the standard processing techniques that remove low and high-frequency
noise from the time-history. Records from analogue instruments are more prone to these problems but even records from digital
instruments, which are becoming increasingly common, can be affected by such errors. Since all strong-motion data is valuable
it is important to know whether any useful information can be obtained from accelerograms that are affected by such problems.
This article examines whether strong-motion records from analogue instruments that are missing their initial part due to late
triggering of the instrument and also strong-motion records from digital instruments with low A/D converter resolution can
be used for response spectral studies. It is found, by simulating such errors on high-quality strong-motion records, that
good response spectral ordinates can be obtained from such `poor-quality' records within the period range of most engineering
interest.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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地震地面运动模型的研究 总被引：1，自引：0，他引：1
地震地面运动被模拟成均值为零的两次过滤Ｇａｕｓｓ白噪声随机过程。第一次过滤削减白噪声的高频含量;第二次过滤削减白噪声的低频含量。根据地震记录的功率谱,使用非线性函数的最小二乘法,确定了两次过滤Ｇａｕｓｓ白噪声随机过程的功率谱密度函数的参数。 相似文献
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Wavelet-based generation of spectrum-compatible time-histories 总被引：6，自引：0，他引：6
This paper deals with the well-known problem of generating spectrum-compatible synthetic accelerograms for the linear and non-linear time-history analyses of structural systems. A wavelet-based procedure has been used to decompose a recorded accelerogram into a desired number of time-histories with non-overlapping frequency contents, and then each of the time-histories has been suitably scaled for matching of the response spectrum of the revised accelerogram with a specified design spectrum. The key idea behind this iterative procedure is to modify a recorded accelerogram such that the temporal variations in its frequency content are retained in the synthesized accelerogram. The proposed procedure has been illustrated by modifying five recorded accelerograms of widely different characteristics such that those are compatible with the same USNRC design spectrum. 相似文献