The response of a concrete element can be expressed in terms of two modes of structural behavior; ductile and brittle. In the ductile mode of response the element mayattain large inelastic deflections without complete collapse, while, in the brittle mode,partial failure or total collapse of the element occurs. The selected behavior of anelement for a particular design is governed by: (1) the magnitude and duration of theblast output, (2) the occurrence of primary fragments, and (3) the function of theprotective structure, i.e., shelter or barrier depending upon the protection level required.