One of the greatest challenges blast engineers face is securing enough standoff for facilities that need to be protected against attacks by vehicle-borne bombs. One solution might require the use of a perimeter blast wall. Depending on their location relative to the protected facility and the standoff distance to the bomb, perimeter blast walls might reduce the blast pressure and impulse from a vehicle bomb. Generally, erecting a blast wall at some distance from the building might provide no appreciable increase in protection for the majority of buildings. However, constructing a blast wall immediately in front of the building might provide significant protection. The blast wall effectively reduces the pressure from a reflected pulse to an incident pulse, permitting reduced safe standoff distances. Additionally, a properly designed perimeter blast walls will stop the effects of fragmentation. Empirical equations, developed by military researchers, might be used to predict the blast pressure and impulse reduction capabilities of a perimeter wall. However, the application of such equations is severely limited by the test parameters used in the equation development. Some design guidelines require that blast walls have a height equal to 1.5 times the protected structure height, and a width equal to twice the protected structure width. Furthermore, the wall must be constructed no further than one story height from the protected face of the building. Hence, blast walls can be massive and aesthetically not pleasant This paper will examine the effectiveness of blast walls in reducing blast pressures and impulses behind the walls. Three-dimensional, Computational Fluid Dynamic (CFD) simulations will be used to calculate the blast pressures for various blast environments. Where applicable, the calculated blast loads will be compared with those obtained using the empirical approach.
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