Modification of Equivalent Acceleration Relation of Horizontal and Vertical Earthquakes in Ground Elliptical Tanks

Modification of equivalent acceleration relation of horizontal and vertical earthquakes in ground elliptical tanks was done in the current study. The seismic analysis of the tank is highly important because by investigating the results obtained from this analysis, a useful recognition of the tank behavior quality can be obtained at the time of a real earthquake. The results of the seismic analysis include the impulsive pressure and the wave height of fluid on different points of the tank. In Housner theory, earthquake equivalent acceleration is a key parameter in calculation of impulsive vibration mode parameters such as impulsive pressure and impulsive force. US nuclear reactors and earthquakes code presented a simple relation to calculate earthquake equivalent acceleration. To obtain more calculation accuracy in the ground elliptical tanks, a suitable equation was provided in the current study for the earthquake equivalent acceleration, by the use of principles of statistical regression. Because of less average error, the use of the equation proposed by this study instead of the equation presented by US nuclear reactors and earthquakes code, provides more accuracy in the tank design applications. By the study of the conclusions of this research, it was revealed that the accuracy index of horizontal and vertical earthquake equivalent acceleration relations developed by this research is 16% and 26% more than that of the corresponding relations of US nuclear reactors and earthquakes code, respectively.