PROTECTION OF STRUCTURES AGAINST AIRBURST USING BARRIERS OF LIMITED ROBUSTNESS.

Abstract

A programme of research was conducted at approximately one-tenth scale to make measurements of the blast environment behind a vertical blast wall when spherical charges were detonated at different stand-off distances from the wall. In contrast to the types of wall that are generally provided for protective purposes, the structures deployed in this study were only sufficiently robust to remain in place while blast wave interaction occurred. They are described as 'partially failing', meaning that they suffered damage as a consequence of the loading they received. Walls were constructed from a range of materials, including plain sand monoliths of different thickness, sand enclosed in scaled geotextile materials, wood, expanded foam plastic and water. Some experiments were conducted using sand enclosed in geotextile material but with the wall being zig-zagged in plan (rather than straight) in order to increase overall stability. Peak overpressures and specific impulses obtained from the pressure-time histories were compared with the results from earlier investigations involving undeforming plane steel cantilever walls. In almost every case the reduction in blast resultants was at least as good as for the undeforming walls. A relationship between the degree of attenuation and the areal density of the wall structure was apparent The results indicate that, for the rapid provision of protection, non-permanent structures can provide a high degree of blast wave attenuation.