understand the author's reference to shear
rods. Possibly he means the longitudinal reinforcement, which it seems
is sometimes calculated to carry 10,000 lb. per sq. in. in shear. The
writer never heard of such a practice.

In regard to stirrups, Mr. Godfrey seems to be in doubt. They certainly
do not act as the rivets of a plate girder, nor as the vertical rods of
a Howe truss. They are best compared with the dowel pins and bolts of a
compound wooden beam. The writer has seen tests made on compound
concrete beams separated by copper plates and connected only by
stirrups, and the strength of the combination was nearly the same as
that of beams made in one piece.

Stirrups do not add much to the strength of the beams where bent bars
are used, but the majority of tests show a great increase of strength
where only straight reinforcing bars are used. Stirrups are safeguards
against poor concrete and poor workmanship, and form a good connection
where concreting is interrupted through inclemency of weather or other
causes. They absolutely prevent shrinkage cracks between the stem and
the flange of T-beams, and the separation of the stem and slab in case
of serious fires. For the latter reason, the writer condemns the use of
simple U-bars, and arranges all his stirrups so that they extend from
6 to 12 in. into the slabs. Engineers are warned not to follow the
author's advice with regard to the omission of stirrups, but to use
plenty of them in their designs, or sooner or later they will thoroughly
repent it.

In regard to bending moments in continuous beams, the writer wishes to
call attention to the fact that at least 99% of all reinforced
structures are calculated with a reduction of 25% of the bending moment
in the center, which requires only 20% of the ordinary bending moment of
a freely supported beam at the supports. There may be some engineers who
calculate a reduction of 33%; there are still some ultra-confident men,
of little experience, who compute a reduction of 50%; but, inasmuch as
most designers calculate with a reduction of only 25%, too great a
factor of safety does not result, nor have any failures been observed on
that account.

In the case of slabs which are uniformly loaded by earth or water
pressure, the bending moments are regularly taken as (_w_ _l^{2}_)/24 in
the center and (_w_ _l^{2}_)/12 at the supports. The writer never
observed any failure of continuous beams over the supports, although he
has