On the Influence of the Shape of Windows on Overpressures and Impulses in Buildings Subjected to External Blast Loading

Abstract

Explosive charges have attracted considerable attention in recent years due to accidental or intentional events involving important structures which have occurred around the world. The activities related to terrorist attacks have increased and, unfortunately, the current trend suggests that they will continue to rise in the future. In relation to the design of structures subjected to blasts there are still many uncertainties in the specialized technical literature. Moreover, many studies done in different countries remain as “classified” documents which can not be accessed by foreign researchers. The main objective of this work is to formulate design recommendations concerning the shape of openings and windows in structures that may be subjected to blasts. With this purpose, numerical studies of a typical building subjected to external blast loadings of 50, and 500 kg of TNT located at different stand-off distances were carried out. Using a hydrocode, the multiple reflections of the pressure wave generated by the explosion, the "Mach effect”, the rarefactions, and the negative phase of the incident pressure wave can be accurately reproduced. The pressure and impulse histories at various points inside the structure caused by the external loads were also determined. Finally, shapes of windows to mitigate the effects of external blast loadings on buildings are recommended.