近断层地震动作用下高耸补压塔地震反应分析

由于近场脉冲地震中含有幅值较大的速度脉冲，其表现出的基本特征通常不同于远场地震。为研究近断层地震和地基刚度对补压塔结构动力响应的影响，以某拟建补压塔为研究对象，考虑流固耦合和地基辐射阻尼，建立水体-结构-基础三维有限元模型，采用时程分析方法研究不同地基刚度、不同地震动类型对结构动力的响应规律。利用1999年集集地震的3组不同类型的地震动记录，即远场、近场无脉冲和近场脉冲型，采用精度较高的波动输入方法和黏弹性人工边界对构筑物进行动力分析。研究表明：不同的地震动特性和土-结构相互作用效应对补压塔的结构响应有显著影响，在地基刚度不大时，近场脉冲型地震位移响应是远场地震的2.5倍以上，鞭稍效应更为明显。近场脉冲型地震动对结构响应影响程度与结构第一周期有显著的相关性。研究结果可为近场区域高耸水工结构设计提供理论依据。

Seismic response of a high pressure regulating tower to near fault earthquakes

Impulsive near field earthquakes often exhibit different characteristics from far field earthquakes due to the larger velocity pulses they produce. In order to study the effects of near fault ground motions and foundation stiffness on the structural dynamic response of the pressure regulating towers, taking a proposed pressure regulating tower project as the research object, we established a three dimensional finite element model of water-structure-foundation using ABAQUS with the consideration of fluid-solid coupling and foundation radiation damping. Three different types of seismic records from the 1999 Chi-Chi earthquake, namely, far field, non impulsive near field and impulsive near field earthquakes, were introduced to the model for the dynamic analysis of the structure using a fluctuating input method with high accuracy and a viscoelastic artificial boundary. The study shows that the input ground motion characteristics and soil-structure interaction have significant effects on the structural response of the pressure regulating tower, and the displacement response of the impulsive near field earthquakes is more than 2.5 times larger than that of the far field earthquakes when the foundation stiffness is small, and the whiplash effect is more obvious. The effects of impulsive near field earthquakes on the structure is highly correlated with the first period of the structure. The results of the study can provide a theoretical basis for the design of high hydraulic structures in the near field region.