Abstract The modal response of liquid-storage steel tanks and the associated prevailing frequencies in the horizontal impulsive mode of vibration are explored by means of earthquake recordings. To this end, a well-documented case study is employed, referring to an instrumented steel cylindrical tank which is a property of the HEL.PE. Oil Company in the Kalochori area, west of Thessaloniki in Northern Greece. The 28.5m-diameter tank has a self-supporting dome roof fixed to the tank walls and it is partially filled with water, corresponding to a ratio of the liquid free surface height to the tank's radius (H/R) at 0.74. Two accelerometric stations are mounted close to the center of the tank roof and on the ground surface at free-field conditions. Seventy four (74) acceleration records from low-intensity earthquake motions are processed to identify the fundamental frequencies of the tank and of the foundation soil from pertinent transfer functions in the frequency domain. The experimental findings are compared with predictions from theoretical formulae recommended by seismic design codes for fixed-base and flexibly-supported tanks, thus allowing the assessment of soil-structure interaction effects on the fundamental period of the tank. A simplified three-dimensional finite-element model of the fluid-tank system resting on flexible supports is also analyzed to provide further insight on the recorded response, as affected by critical structural features of the tank. Results highlight a dominant rigid-body mode which is associated to the lateral fundamental period of the flexibly-supported system, in agreement with relevant code provisions for tanks with H/R below unity.

中文翻译：

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包括土-结构相互作用的仪表钢储水罐的模态响应

摘要 通过地震记录研究了储液钢罐的模态响应以及水平脉冲振动模式下的相关主导频率。为此，我们采用了一个有据可查的案例研究，涉及作为 HEL.PE 特性的仪表钢圆柱形储罐。位于希腊北部塞萨洛尼基以西 Kalochori 地区的石油公司。直径为 28.5m 的储罐有一个固定在储罐壁上的自支撑圆顶，其中部分充满水，对应于液体自由表面高度与储罐半径 (H/R) 的比值 (H/R) 为 0.74。在自由场条件下，两个加速度站安装在靠近罐顶中心和地面上。处理来自低强度地震运动的七十四 (74) 条加速度记录，以根据频域中的相关传递函数识别储罐和地基土壤的基本频率。将实验结果与抗震设计规范推荐的固定底座和柔性支撑储罐的理论公式预测进行比较，从而可以评估土壤-结构相互作用对储罐基本周期的影响。还分析了位于柔性支撑上的流体罐系统的简化三维有限元模型，以进一步了解记录的响应，因为受罐的关键结构特征的影响。