In the ordinary adhesion test, the block of concrete is held by the jaws
of the machine and the rod is pulled out; the concrete is clearly in
compression.

The underside of continuous beams is in compression near the supports,
yet no one will say that steel rods cannot take any stress there. It is
quite surprising to learn that there are engineers who still doubt the
advisability of using bent-up bars in reinforced concrete beams.
Disregarding the very thorough tests made during the last 18 years in
Europe, attention is called to the valuable tests on thirty beams made
by J.J. Harding, M. Am. Soc. C. E., for the Chicago, Milwaukee and St.
Paul Railroad.[H] All the beams were reinforced with about 3/4% of
steel. Those with only straight rods, whether they were plain or
patented bars, gave an average shearing strength of 150 lb. per sq. in.
Those which had one-third of the bars bent up gave an average shearing
strength of 200 lb. per sq. in., and those which had nearly one-half of
the rods bent up gave an average shearing strength of 225 lb. per sq.
in. Where the bent bars were continued over the supports, higher
ultimate values were obtained than where some of the rods were stopped
off near the supports; but in every case bent-up bars showed a greater
carrying capacity than straight rods. The writer knows also of a number
of tests with rods fastened to anchor-plates at the end, but the tests
showed that they had only a slight increase of strength over straight
rods, and certainly made a poorer showing than bent-up bars. The use of
such threaded bars would increase materially the cost of construction,
as well as the time of erection.

The writer confesses that he never saw or heard of such poor practices
as mentioned in the author's third point. On the other hand, the
proposed design of counterforts in retaining walls would not only be