大型混凝土储液罐考虑穹顶效应的动力响应研究

DYNAMIC RESPONSE ANALYSIS OF LARGE CONCRETE STORAGE TANK CONSIDEING THE DOME EFFECT

简化力学模型是大型储罐抗震设计的重要依据。在以往的研究中,对于大型储罐的简化模型多不考虑穹顶对结构体系动力响应的影响。该文推导了考虑穹顶作用的简化模型,对某30万方的混凝土储罐进行了数值计算,并与Housner模型进行对比,给出了动水压力的截断位置;使用振型分解法对高阶振型进行解耦,验证了高阶振型对储罐结构动力响应的影响;对比了考虑穹顶作用的简化力学模型与忽略穹顶作用的简化力学模型的储罐结构动力响应。研究表明:动水压力至少在第三项截断,形函数采用第二阶悬臂梁振型,并至少叠加一阶振型时,可保证结构的计算精度,忽略穹顶的作用会高估结构的基底剪力和倾覆力矩。

Simplified mechanical model is important for seismic design of large storage tanks.In available studies,the simplified models for large storage tanks mostly ignored the influence of the dome.In this paper,a simplified mechanical model considering the effect of the dome was derived and numerical calculations were carried out for a concrete storage tank of 300,000 m3,and the truncation position of the hydrodynamic pressure with guaranteed accuracy was given,and the model was compared with the Housner’s model to confirm the accuracy of the model.The effect of higher mode was investigated using the mode superposition method,and the dynamic response of the storage tank structure was compared between the simplified mechanical models considering and ignoring the effect of the dome.The results show that to ensure the accuracy of the calculation,the hydrodynamic pressure should be truncated at least in the third term,and the shape function should use the second order cantilever beam mode,as well as superimpose at least one order mode.Ignoring the dome effect will underestimate the base shear and overturning moment of the system.