d who was not a destructive critic. If showing up
errors and faults is destructive criticism, we cannot have too much of
it; in fact, we cannot advance without it. If engineering practice is to
be purged of its inconsistencies and absurdities, it will never be done
by dwelling on its excellencies.

Reinforced concrete engineering has fairly leaped into prominence and
apparently into full growth, but it still wears some of its
swaddling-bands. Some of the garments which it borrowed from sister
forms of construction in its short infancy still cling to it, and, while
these were, perhaps, the best makeshifts under the circumstances, they
fit badly and should be discarded. It is some of these misfits and
absurdities which the writer would like to bring prominently before the
Engineering Profession.

[Illustration: FIG. 1.]

The first point to which attention is called, is illustrated in Fig. 1.
It concerns sharp bends in reinforcing rods in concrete. Fig. 1 shows a
reinforced concrete design, one held out, in nearly all books on the
subject, as a model. The reinforcing rod is bent up at a sharp angle,
and then may or may not be bent again and run parallel with the top of
the beam. At the bend is a condition which resembles that of a hog-chain
or truss-rod around a queen-post. The reinforcing rod is the hog-chain
or the truss-rod. Where is the queen-post? Suppose this rod has a
section of 1 sq. in. and an inclination of 60 deg. with the horizontal, and
that its unit stress is 16,000 lb. per sq. in. The forces, _a_ and _b_,
are then 16,000 lb. The force, _c_, must be also 16000 lb. What is to
take this force, _c_, of 16,000 lb.? There is nothing but concrete. At
500 lb. per sq. in., this force would require an area of 32 sq. in. Will
some advocate of this type of design please state where this area can be
found? It must, of necessity, be in contact with the rod, and, for
structural reasons, because of the lack of stiffness in the rod, it
would have to be close to the point of bend. If analogy to the
queen-post fails so completely, because of the almost complete absence
of the post, why should not this borrowed garment be discarded?

If this same rod be given a gentle curve of a radius twenty or thirty
times the diameter of the rod, the side unit pressure will be from
one-twentieth to one-thirtieth of the unit stress on the steel. This
being the case, and being a simple principle of mechanics which ought to
be thoroughly un