Prediction of debris launch velocity of vented concrete structures under internal blast

The debris hazard resulting from an internal explosion is a major concern in the design of explosives storage magazines and protective structures. This paper presents a simple predictive method for the debris launch velocity from a concrete storage magazine subjected to internal blast load, with particular focus on the effect of initial vent openings. The method is developed using a combined theoretical–empirical approach, in which the debris launch velocity is formulated based on energy considerations, whereas the reduction coefficient of pressure caused by the flow of explosive gas from the vent openings is established from experimental data. The analytical model is verified against available experimental data and other numerical predictions. Example cases are given to demonstrate the application of the general formulation to particular structures and illustrate the effect of venting and its location on the debris velocity for structures of different sizes.