Dynamic Instability of Soil-SDOF Structure Systems under Far-Fault Earthquakes
Dynamic Instability of Soil-SDOF Structure Systems under Far-Fault Earthquakes
复制标题
远断层地震下土壤-单自由度结构系统的动力失稳
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
M. H. Tehrani
中科院分区：
文献类型：
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作者：
F. Khoshnoudian;E. Ahmadi;M. Kiani;M. H. Tehrani
采用参数化方法研究了土-结构体系在远断层地震作用下的动力失稳问题。上部结构和土壤被模拟为一个双线性单自由度（SDOF）振子和基于锥模型的概念，分别。结果表明，土体的柔性使体系的动力不稳定性增加，随着无量纲频率的增加，强度折减系数大大降低。此外，增加纵横比导致较低的崩溃强度降低因子。然而，它的影响被发现是微不足道的。振动周期和屈服后坡度对强度折减系数的影响与基础固定情况相同。此外，从精确的时程分析中得出的倒塌强度折减系数与FEMA 440中针对固定基础条件提出的系数相比，显示出极大的低估，在几乎所有情况下误差大于20%，在极端情况下误差大于60%。最后，公式校准使用非线性回归分析，以估计倒塌强度折减系数的土壤结构系统。
A parametric study is devoted to investigating the dynamic instability of soil-structure systems under far-fault earthquakes. The superstructure and soil are simulated as a bilinear single-degree-of-freedom (SDOF) oscillator and based on the cone model concept, respectively. The results show that soil flexibility makes the system dynamically more unstable and that as the non-dimensional frequency increases, the collapse strength-reduction factor highly decreases. Moreover, increasing the aspect ratio leads to a lower collapse strength-reduction factor. However, its effect is found to be negligible. The effects of vibration period and post-yield slope on the collapse strength-reduction factor are the same as on the fixed-base condition. Additionally, comparison of collapse strength-reduction factors resulting from exact time history analyses with those proposed in FEMA 440 for the fixed-base condition shows a great underestimation with errors larger than 20% at approximately all cases and 60% at extreme cases. Finally, a formulation is calibrated using nonlinear regression analysis in order to estimate collapse strength-reduction factors of soil-structure systems.