ul in this respect, brackets being nearly always included. True, if
brackets are omitted, some compensation is provided by the strengthening
which horizontal bars may give by extending through this region, but
sufficient additional compressive resistance is rarely afforded thereby.
Perhaps the best way to overcome the difficulty, without resorting to
brackets, is to increase the compressive resistance of the concrete, in
addition to extending horizontal steel through it. This may be done by
hooping or by intermingling scraps of iron or bits of expanded metal
with the concrete, thereby greatly increasing its resistance. The
experiments made by the Department of Bridges of the City of New York,
on the value of nails in concrete, in which results as high as 18,000
lb. per sq. in. were obtained, indicate the availability of this device;
the writer has not used it, nor does he know that it has been used, but
it seems to be entirely rational, and to offer possibilities.

Another practical test, which indicates the value of proper
reinforcement, may be mentioned. In a storage warehouse in Canada, the
floor was designed, according to the building laws of the town, for a
live load of 150 lb. per sq. ft., but the restrictions being more severe
than the standard American practice, limiting the lever arm of the steel
to 75% of the effective depth, this was about equivalent to a 200-lb.
load in the United States. The structure was to be loaded up to 400 or
500 lb. per sq. ft. steadily, but the writer felt so confident of the
excess strength provided by his method of reinforcing that he was
willing to guarantee the structure, designed for 150 lb., according to
the Canadian laws, to be good for the actual working load. Plain, round,
medium-steel bars were used. A 10-ft. panel, with a beam of 14-ft. span,
and a slab 6 in. thick (not including the top coat), with 1/2-in. round
bars, 4 in. on centers, was loaded to 900 lb. per sq. ft., at which load
no measurable deflection was apparent. The writer wished to test it
still further, but there was not enough cement--the material used for
loading. The load, however, was left on for 48 hours, after which, no
sign of deflection appearing, not even an incipient crack, it was
removed. The total area of loading was 14 by 20 ft. The beam was
continuous at one end only, and the slab only on one side. In other
parts of the structure conditions were better, square panels being
possible, with reinforce