Effectiveness of blast walls designed for blast shielding

In a dense urban environment, it is both very expensive and difficult to harden and retrofit an existing building in order to minimize damage from blast loads. An alternative method of protection is to construct a perimeter wall around and at some distance from the building. Such a blast wall will provide a stand-off distance to protect the structure from an external explosion. Moreover, it will act as an obstacle between the blast source and the building in the direction of the blast wave propagation. Therefore, some of the explosive energy will be reflected back, and the pattern of the distribution of the blast pressure on the structure behind the barrier will be changed and the peak pressure will be reduced. A blast damage assessment of buildings and structural elements requires an accurate prediction of the blast loads in terms of the peak pressures and impulses. The purpose of this paper is to shed light on the effectiveness of existing approaches to the evaluation of the effect of blast loads on structures as well as on the existing methods to predict the blast effects on structures behind blast walls. ProSAir (Propagation of Shocks in Air) is a compressible Computational Fluid Dynamics package that is used here to conduct a numerical study to investigate the effectiveness of blast walls. The results of the blast forces obtained without blast walls are the baseline for making a comparison with the results obtained with blast walls.