PROTECTION OF STRUCTURES AGAINST AIRBLAST USING BARRIERS OF LIMITED ROBUSTNESS

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 dis tances from the wall. In contrast to the types of wall that are genera lly provided for protective purposes, the structures deployed in this study were only sufficiently robust to remain in place while blast wav e interaction occurred. They are described as 'partially failing', mea ning that they suffered damage as a consequence of the loading they re ceived. Walls were constructed from a range of materials, including pl ain sand monoliths of different thickness, sand enclosed in scaled geo textile materials, wood, expanded foam plastic and water. Some experim ents were conducted using sand enclosed in geotextile material but wit h 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 resul ts from earlier investigations involving undeforming plane steel canti lever walls. In almost every case the reduction in blast resultants wa s at least as good as for the undeforming walls. A relationship betwee n the degree of attenuation and the areal density of the wall structur e was apparent. The results indicate that, for the rapid provision of protection, non-permanent structures can provide a high degree of blas t wave attenuation.