William Howard Taft

“ The expansion and improvement of the art of reinforcing concrete began several decades ago. There were two different needs, one was for strengthening concrete beams, and the other for strengthening concrete columns. The term 'reinforcing bar' is usually applied in the art to a rod or bar used to reinforce a concrete beam against the tension longitudinal of the beam itself. The concrete itself has great power of resisting compression, but it has not tensile strength, and its weakness manifests itself in cracking along the lower half of the beam. ”

“ More than this, in the very field itself, there was a prior German patent of Kesserling & Moller, showing the use of the kerf for spacing a spiral in reinforcing concrete. It does not seem to us that it involved real invention merely to add a spur or clamp, or to peen or hammer down the edges of the kerf, so as to fix the spiral rod firmly. ”

“ This was the field which Vandenburgh entered and devised an arrangement, shown in Figure 1 of his drawings, of a reinforcing bar imbedded in the lower part of the beam with transverse loops or spirals, part on one side of the center of the bar and part on the other and fitted rigidly into the bar so that those on each side leaned at an angle away from the center and in an opposite inclination from those on the other. ”