近海域地震动的时频特征与工程特性

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振动与冲击 ›› 2018, Vol. 37 ›› Issue (16) : 227-233.

论文

近海域地震动的时频特征与工程特性

陈苏1，周越1，李小军1,2，傅磊1

作者信息 +

Time-frequency and engineering characteristics on offshore ground motion

CHEN Su1, ZHOU Yue1, LI Xiaojun1,2， FU Lei1

Author information +

文章历史 +

摘要

利用美国加州及日本相模湾近海域地震台站采集的地震动记录，采用希尔伯特-黄变换方法计算得到近海域地震动时频分布特征；将其加速度反应谱、动力放大系数β谱与不同工程领域抗震设计规范进行对比。研究结果表明：近海域地震动含有丰富的长周期成分，优势能量集中于长周期与特长周期段内；归一化边际谱能量分布与震中距有一定的相关性；近海域地震动水平向分量强度远高于其竖向分量。进一步发现，多数近海域地震动反应谱动力放大系数β谱峰值远超目前常用规范标准反应谱的平台值，也就是近海域地震动反应谱的中长周期值远大于现有抗震设计规范的取值，采用现有陆域地震动设计规范开展近海工程地震安全性设计存在风险。近海域地震动长周期特性在大跨桥梁、油气平台等重大近海工程设计中应得到充分关注。

Abstract

Based on the offshore ground motions recorded in California, U.S, and the Sagami trough zone, Japan, the offshore ground motions time-frequency distribution features were analyzed by the Hilbert-Huang transform method.The acceleration spectrum and dynamic amplification factor β spectrum were compared with the design spectra in relevant seismic design standards.The research results indicate that the offshore ground motions contain a wealth of long period component sand that the long period and ultra-long period components were dominant in frequency range.The normalized marginal spectrum’s energy distribution was correlated with epicenter distance.The horizontal offshore ground motion’s intensity was much greater than that of the vertical ground motion.Moreover, findings show that the dynamic amplification factor β-values of most offshore ground motions are greater than the current platform value of seismic design standards used, which means that their long-period components are much larger than the seismic design standards(i.e., it is risky to use offshore facility seismic design by land seismic design standards).In view of these results, there are many engineering structures such as long-span bridges and oil and gas platforms whose long period components of offshore ground motions warrant more attention in offshore engineering structure seismic design.

导出引用

陈苏1，周越1，李小军1,2，傅磊1. 近海域地震动的时频特征与工程特性[J]. 振动与冲击, 2018, 37(16): 227-233

CHEN Su1, ZHOU Yue1, LI Xiaojun1,2， FU Lei1. Time-frequency and engineering characteristics on offshore ground motion[J]. Journal of Vibration and Shock, 2018, 37(16): 227-233

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