Characteristics of gas explosion loads and structural responses of blast wall on FPSO

Gas explosions generally cause catastrophic damage to surrounding structures and humans. The application of blast wall can effectively prevent the damage. The uniform explosion load is widely used in assessing structural response, but it cannot represent the non-uniform characteristic of actual explosion pressures. The main contents of this paper are to study the effect of gas cloud characteristics on explosion pressure distribution, and analyze the effect of non-uniform loads on structural responses. The results reveal that the explosion loads have strongly spatial inhomogeneous when explosion scenarios have large sized cloud or long combustion distance. By establishing the overpressure-probability exceedance curves for uniform loading method and distributed loading method, based on the given accident frequency several design loads are determined. The structural responses of blast wall under design loads are assessed based on explosion evaluation acceptance criteria. It can be seen that the use of uniform loading method underestimates the structural response and misjudges the deformation pattern compared to actual explosion loads. Global and local explosion pressures should be considered simultaneously in the design specification. The overpressure-probability exceedance curves for non-uniform explosion pressures are recommended to establish the design load for blast wall.