Simplification of fully confined blasts for structural response analysis

A blast in a fully confined environment magnifies the blast loading resulting in more serious damage to surrounding structural members. To protect critical infrastructure against confined blasts, the confinement effects need to be fully taken into consideration. In this paper, a procedure to simplify the highly irregular nature of fully confined blast loads was developed for the purpose of being incorporated into a structural response analysis tool such as a Pressure Impulse Diagram. It was found that when the centroid of the simplified confined blast load was close to the centroid of the actual confined blast load, whilst keeping the total impulse the same, the response of a member caused by the simplified confined blast load was similar to that produced by the actual confined blast load. This concept to accurately simplify an irregular confined blast based on structural response was then used to construct the method of simplification. This method of simplification was then tested using a structural response model for the purposes of validation and suitability. A comparison was then made against the current UFC guidelines predictions to assess its accuracy.