Yield Effects on the Response of a Buried Blast Shelter

Abstract : The Federal Emergency Management Agency has tasked the US Army Engineer Division, Huntsville, to design a Keyworker blast shelter. In conjunction with this project, the US Army Engineer Waterways Experiment Station conducted a series of tests to investigate the effects of variations in weapon yield and the absence of wall stirrups on the structural response of a reinforced concrete box-type shelter. The VSBS computer program was also utilized in these tests to confirm calculated yield effects on buried structures prior to the MINOR SCALE Event which took place in June 1985. Four 1/4-scale structural models were exposed to high-explosive tests simulating overpressures from approximately 1/2- to 10-KT nuclear bursts. Based on test results, the VSBS program appears to be an accurate method for predicting the variations in yield and overpressure which are required to cause a specified level of damage. Modification of the resistance function used in the VSBS program is required to better predict small plastic deformations. Test results showed that although wall stirrups may not be required to prevent failure at the 50-psi level, including them ensures that the wall will not fail prematurely at slightly higher overpressures. Keywords: Buried shelters, Civil defense, Shear stirrups, Slab capacity, Slabs, Soil arching, Weapon yield effects.