Strengthened Concrete.

The authors classify as "strengthened" that concrete which has less than specified minimum reinforcement thus distinguishing it from "plain" concrete and "reinforced" concrete. An approach to design is described for ground supported elements which introduces a straight-line transition between the stress, as a function of moment capacity, developed by the plain concrete and that produced by the minimum reinforcement using working stress design. With this approach, amounts of reinforcing steel below the specified minimums are given credit for serving as a "strengthening" influence on plain concrete [ABSTRACT FROM AUTHOR]