9402563 Darwin The research represents the continuation of the first major revaluation of reinforcing bar geometry in the United States in over forty years. The study capitalizes on current research efforts to develop new deformation patterns that optimize bar development characteristics. Tests are used to evaluate the improvement in bond provided by the new bars, both with and without epoxy coating, as a function of confining reinforcement, cover, and bar spacing. The bond characteristics of the new bars also evaluated under cyclic loading. Fracture mechanics concepts and load and resistance factor design techniques are used to develop rational, rather than empirical, design procedures. The research is carried out in conjunction with reinforcing bar producers, fabricators, coating applicators, and epoxy powder manufacturers. Emphasis is placed on improved bar deformation patterns that are cost effective and practical.
