A methodology for predicting far-field blast loading on structures

Structural engineers are often tasked with the challenge of enhancing the resilience of buildings and structures to withstand blast loading from the detonation of energetic materials. Such loading typically occurs during terrorist attacks and from accidental explosions in nearby chemical and explosive storage facilities. However, existing methods for predicting the governing blast loading on a structure, through consideration of multiple explosion scenarios, are unsuitable for most practising structural engineers. This paper will address the need for fast-running tools for predicting blast loads on structures in the far-field by presenting the semi-empirical EMBlast method that calculates free-field and reflected pressure-time histories for both the positive and negative phase. For finite size target surfaces, this method also accounts for clearing effects, a phenomenon that results in gradually reducing the reflected pressures on the front face of a building, to the lower free-field pressures experienced by the sides and roof. To validate the predictions of the EMBlast method in the far-field, computational fluid dynamic analyses are performed over a long-range of scaled distances. Furthermore, the EMBlast predictions are also compared with the results from published blast tests, existing empirical methods and computational fluid dynamic simulations identified in the literature.