Tests and Analyses of 1/4-Scale Upgraded Nine-Bay Reinforced Concrete Basement Models

Abstract : Methods that can be used to increase (upgrade) the blast resistance of existing two-way reinforced concrete slab systems to a value near 50-psi overpressure from a 1-mt weapon were evaluated, Two nine-bay prototype structures, a flat plate and a two-way slab with beams, were designed in accordance with the 1977 ACI Code. Each structure had a basement area 60 feet square. A 1/4-scale model of each prototype was constructed, upgraded with 4- by 4-inch timber posts, and statically tested in the Large Blast Load Generator at the U.S. Army Engineer Waterways Experiment Station. The timber posts placement scheme was based upon yield-line analyses, a study of moment-thrust interaction diagrams for sections of the slabe, and punching shear evaluations. The upgraded flat plate was tested first, and the upgrading scheme was then modified for the slab with beams model. The flat plate upgraded at locations 1/4 of the span length, and the two-way slab with beams structure was upgraded at locations 1/3 of the span length.