Analysis of the Behaviour of the Floating Roof in a Cylindrical Storage Tank Subjected to Seismic Excitation for the Mitigation of Fire Risk

Natural Hazard triggering Technological Disasters (NaTech) are accidents resulting from natural hazards, such as earthquakes, interacting with industrial risks. Seismic damage to the equipment of industrial plants can lead to major accidents such as explosions, fires or hazardous releases. In this framework, the cylindrical liquid storage tank with floating roof is a common equipment vulnerable to earthquakes. In particular, rim seal fires can be initiated by damage to the sealing system. Impact between metallic parts, such as the bumper bars and the tank shell, may be the cause. The aim of this work is to investigate the horizontal dynamic behaviour of the floating roof of a tank under seismic excitation in order to assess and mitigate the associated risk of major accidents. For this purpose, a simplified model has been developed, considering the bumper bars rigid and partially deformable. Finally, some fragility curves have been realized to estimate the probability of occurrence of a given maximum contact force as a parameter of structural damage and possible ignition of fire.