Author(s)

R. Anaya, O. T. Inal, P. F. Gerity & D. H. Lopez

Abstract

Floor slabs of multi-story buildings are susceptible to the detonation of a truck bomb at the street level. A method of improving the survivability of these floor slabs against explosions from below is to retrofit their top surfaces with fiber/epoxy composites. In this regard, fiberglass and carbon unidirectional fabrics were studied to determine which is the most cost effective for such reinforcement. The optima in the number of plies and the effect of strain rate were also scrutinized. Our results indicate that carbon fibers provide the strongest and most cost effective concrete reinforcement against roadside initiation of an explosive. Also, plying was found to have more than twice the effect of strain rate in determining the failure load for the concrete. Keywords: retrofit, reinforcement, fiberglass, carbon fibers. 1 Introduction To determine the best method of reinforcing existing structures and thus minimize loss of life in the event of a truck bomb detonation or an earthquake, a series of experiments were made at New Mexico Tech (1). In studying the effect of truck bombs on typical office buildings, it was determined that the floor slabs of multistory buildings were particularly vulnerable to the effects of a blast or an earthquake (2). Typical floor slabs for an office building are reinforced with steel to resist force of gravity; i.e. placed at the bottom to resist the tensile stress. However, during an explosion from below, the pressure created by the blast causes the floor slab to bow upward and thus reverse the location of the tensile stress. The bowing of the floor slab may also cause the concrete to detach from the street reinforcement, resulting in localized failure of the slab. Furthermore, the bowing of the floor slab may cause it to detach from the support columns,

Keywords

retrofit, reinforcement, fiberglass, carbon fibers.