Evaluation of the Design Pressure and Failure Modes for the API 12F Shop Welded Flat Bottom Tanks for Oil Storage

This study aims to determine the failure modes of the eleven API 12F shop welded tanks plus two proposed new sizes through finite element and stress analysis of more than 350 different models. Four separate analysis where carried out throughout this investigation. An elastic stress analysis considering non-linear deformations was performed to determine the yielding pressure of the tanks and maximum design pressure. An elastic buckling mode analysis evaluated the potential buckling pressure as a failure mode of the tanks. The redistribution of stresses due to inelastic deformations and plastic collapse were evaluated through an elastic-plastic stress analysis. Finally, a wind load analysis was developed to study the stress levels and uplift deformation of the API 12F tank with greatest aspect ratio (H/D). The presented research provides meaningful engineering calculations to evaluate the current design and capacity of the API 12F flat bottom tanks guaranteeing a safe performance of the equipments.