Seismic fragility analysis of an anchored vertical gas steel storage tank using tri-axial shaking table testing

Abstract

Hydrogen and gas storage tanks installed in facilities are typically vertical cylindrical structures made of steel. To allow for the discharge of stored materials, these tanks are anchored onto concrete blocks with sufficient height. However, this design results in a higher center of gravity, making the tanks more vulnerable to external forces such as earthquakes. This study fabricated a storage tank model and foundation concrete based on the results of the field investigation of the hydrogen storage tank. Then, an artificial earthquake was generated by referring to ICC-ES AC 156, a shaking table test method for non-structural elements. Experimenting on a full-scale structure is ideal; however, a storage tank model was fabricated and settled on the foundation concrete for tri-axial shaking table testing due to limited testing facilities and equipment performance. In the shaking table test, the presence or absence of water inside the storage tank was set as the condition for storing gases and liquids. The seismic behavior characteristics and failure mode of the storage tank model fixed in the foundation concrete were analyzed using the testing results. A seismic fragility curve was drawn up, and the high confidence and low probability of failure (HCLPF) was calculated.