Evaluation of Seismic Resistance Capacity on Supporting Structure of Spherical Tank using Static Load Experiment

Abstract

Significant fire and explosion accident on spherical tanks for Liquefied Petroleum Gas (LPG) storage was induced by the strong ground motion of the 2011 Great East Japan Earthquake. Steel pipe braces were broken due to the strong seismic inertia force, and then buckling of support legs was occurred. To prevent recurrence, reinforcing the intersection of braces was needed. The authors investigated the fracture mechanism of spherical tank and the effectiveness of reinforcement by Finite Element Analysis and shaking table test. However, the static relation between force and displacement or strain is not clear yet. In this study, we conducted static tests using a plane of structure of spherical tank. From the test results, it was concluded the effectiveness of reinforcement of the pipe braced supporting frame of a spherical tank as follows; (1) In a case of brace intersection was reinforced, the rigidity of the supporting frame increased. (2) Fracture mechanisms of the steel pipe brace was different from without reinforcement to with reinforcement.