e
next, 12 in., etc., up to a maximum, throughout the mid-section, of 15
in. Each U-bar was provided with a hook at its upper end, as shown in
Plate III, and engaged the slab reinforcement, which in this case was
expanded metal. Two of the 1-1/8-in. bars were bent up and carried
across the support. At the point of bending up, where they passed the
single horizontal bar, which was superimposed, a lock-bar was inserted,
by which the pressure of the bent-up steel against the concrete, in the
region of the bend, was taken up and distributed along the horizontal
bar. This feature is also shown in Fig. 14. The bars, after being
carried across the support, were inclined into the adjacent span and
provided with a liberal, well-rounded hook, furnishing efficient
anchorage and provision for reverse stresses. This was at one end only,
for--to make matters worse--the other end was a wall bearing;
consequently, the benefit of continuity was denied. The bent-up bars
were given a double reverse bend, as already described, carrying them
around, down, in, and up, and ending finally by clasping them in the
hook of the horizontal bar. This apparently stiffened up the free end,
for, under the test load, its action was similar to that of the
completely restrained end, thus attesting the value of this method of
end-fixing.

The writer has consistently followed this method of reinforcement, with
unvaryingly good results, and believes that, in some measure, it
approximates the truth of the situation. Moreover, it is economical, for
with the bars bent up over the supports in this manner, and positively
anchored, plenty of U-bars being provided, it is possible to remove
the forms with entire safety much sooner than with the ordinary methods
which are not as well stirruped and only partially tied across the
supports. It is also possible to put the structure into use at an
earlier date. Failure, too, by the premature removal of the centers, is
almost impossible with this method. These considerations more than
compensate for the trouble and expense involved in connection with such
reinforcement. The writer will not attempt here a theoretical analysis
of the stresses incurred in the different parts of this beam, although
it might be interesting and instructive.

[Illustration: FIG. 14.]

The concrete, with the reinforcement disposed as described, may be
regarded as reposing on the steel as a saddle, furnishing it with a
rigid jacket in which to