近断层脉冲型地震动下位移谱阻尼修正系数

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振动与冲击 ›› 2011, Vol. 30 ›› Issue (12) : 108-113,.

论文

近断层脉冲型地震动下位移谱阻尼修正系数

郝安民1; 周德源1; 李亚明2; 张晖2

作者信息 +

subjected to pulse-type motions in the near-fault region

HAO An-min1; ZHOU De-yuan1; LI Ya-ming2; ZHANG Hui2

Author information +

文章历史 +

摘要

现行规范采用阻尼修正系数（DMF）调整阻尼比不同于5%时的弹性位移反应谱，然而未考虑到近断层脉冲型地震动的影响。本文选取了代表性前方向性脉冲记录，研究了矩震级、场地类别和距离对脉冲周期的影响，同时指出脉冲周期与相应伪速度谱峰值周期之间具有较好的线性相关性，然后以周期与脉冲周期比和阻尼比为双变量，采用Levenberg–Marquardt算法进行非线性回归分析，提出了能够较为准确反映数据点分布规律的DMF模型。结果表明，随着脉冲周期的减小，DMF峰值对应的周期越小，而在中长周期范围DMF越趋近于1.0；与现行规范相比，模型MDF强烈依赖于脉冲周期、结构振动周期和阻尼比，且当三者位于不同取值范围时，规范DMF过低或过高

Abstract

Damping modification factors (DMF) are used in modern seismic codes to adjust elastic response spectral values corresponding to 5% of viscous damping to other damping levels. However, codes have the disadvantage of neglecting the impact of pulse-type motions. This study examined the influence of moment magnitude, site classes and distance on pulse periods by representative forward-directivity ground motion records with distinct velocity pulses. Furthermore, Pulse periods were confirmed to possess better linear relationship with periods corresponding to the peak values of pseudo-velocity spectral. Finally, Nonlinear regression analyses were conducted with the Levenberg–Marquardt method. The resulting equations, as a function of both normalized periods and damping ratios, for DMF successfully represented data distribution. The results show that，with the decrease of pulse periods, periods corresponding to DMF peak values reduce and DMF approach 1.0 at middle and long period range. In contrast to the considerations of current seismic codes, DMF are strongly dependent on pulse periods, the periods of structural vibration and damping ratios, and that in comparison with the DMF proposed by the authors, current DMF are shown to be either too low or too high, depending on pulse periods, period range, damping ratios.

导出引用

郝安民;周德源;李亚明;张晖 . 近断层脉冲型地震动下位移谱阻尼修正系数[J]. 振动与冲击, 2011, 30(12): 108-113,

HAO An-min;ZHOU De-yuan;LI Ya-ming;ZHANG Hui. subjected to pulse-type motions in the near-fault region[J]. Journal of Vibration and Shock, 2011, 30(12): 108-113,