Study on Installation of Ring Stiffeners to Prevent Buckling of Aboveground Oil Storage Tanks under External Liquid Pressure of Tsunami

Abstract

Powerful tsunami attacked to the northeast coast of Japan due to the Great East Japan Earthquake occurred on March 11, 2011. Some aboveground oil storage tanks (ASTs) were subjected to external liquid pressure of the tsunami. An effective method to prevent the buckling of existing ASTs under external liquid pressure is to install ring stiffeners on the shell plate. In this paper, the approximate minimum required number of ring stiffeners and their installed location of ASTs are determined. The optimum design method which repeats the procedure to increase the buckling liquid height by installing a ring stiffener at the peak location of buckling mode is used. This method was proposed in the author's previous paper. The bifurcation buckling analysis is the axisymmetric shell finite element method. As a result, the two ASTs of 10,000 m3 and 90,000 m3 require 14 ring stiffeners in each case when external liquid height is set to the same as the design internal liquid height.