Response of the Flash X-Ray Building at Site 300 to Explosions on Its Firing Table,
LAWRENCE LIVERMORE NATIONAL LAB LIVERMORE CA
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The response of the new high-explosive Flash X-ray Radiography Facility at Bunker 801 at LLNL Site 300 to explosions on its firing table has been measured. Seven charges of the high explosive C-4, with increasing weights of from 18 to 585 lb, were detonated. Charges were placed on a pea-gravel firing table on the radiographic axis 10 ft from the face of the steel bullnose protection plate. No noteworthly damage to the new building or its installed equipment occurred during these tests. Strains on 46 strain gauges were recorded during the explosive tests. During construction of the facility, these gauges had been welded to the steel reinforcing bars in various locations, or suspended between them, and were then embedded in structural concrete. The gauges recorded strains as high as 220 micro-in.in., which is equivalent to a stress of 5600 psi in steel. All elements of the structure remained well below their elastic limits, and should remain within these limits when subjected to detonations of up to 1000 lb of TNT on the firing table. The measured strains were less than those given by simple engineering calculations by factors of from 1.7 to 3.9. Several safety factors and conservative simplifying assumptions were included in the strain calculations, and this may account for the large differences.