ment both ways, and with continuity, both of
beams and slabs, virtually in every direction, end spans being
compensated by shortening. The method of reinforcing was as before
indicated. The enormous strength of the structure, as proved by this
test, and as further demonstrated by its use for nearly two years, can
only be explained on the basis of the continuity of action developed and
the great stiffness secured by liberal stirruping. Steel was provided in
the middle section according to the rule, (_w_ _l_)/8, the span being
taken as the clear distance between the supports; two-thirds of the
steel was bent up and carried across the supports, in the case of the
beams, and three-fourths of the slab steel was elevated; this, with the
lap, really gave, on the average, four-thirds as much steel over the
supports as in the center, which, of course, was excessive, but usually
an excess has to be tolerated in order to allow for adequate anchorage.
Brackets were not used, but extra horizontal reinforcement, in addition
to the regular horizontal steel, was laid in the bottom across the
supports, which, seemingly, was satisfactory. The columns, it should be
added, were calculated for a very low value, something like 350 lb. per
sq. in., in order to compensate for the excess of actual live load over
and above the calculated load.

This piece of work was done during the winter, with the temperature
almost constantly at +10 deg. and dropping below zero over night. The
precautions observed were to heat the sand and water, thaw out the
concrete with live steam, if it froze in transporting or before it
was settled in place, and as soon as it was placed, it was decked
over and salamanders were started underneath. Thus, a job equal in every
respect to warm-weather installation was obtained, it being possible to
remove the forms in a fortnight.

[Illustration: PLATE IV, FIG. 1.--SLAB AND BEAM REINFORCEMENT
CONTINUOUS OVER SUPPORTS. SPAN OF BEAMS = 14 FT. SPAN OF SLABS = 12 FT.
SLAB, 6 IN. THICK.]

[Illustration: PLATE IV, FIG. 2.--REINFORCEMENT IN PLACE OVER ONE
COMPLETE FLOOR OF STORAGE WAREHOUSE. SLABS, 14 FT. SQUARE. REINFORCED
TWO WAYS. NOTE CONTINUITY OF REINFORCEMENT AND ELEVATION OVER SUPPORTS.
FLOOR DESIGNED FOR 150 LB. PER SQ. FT. LIVE LOAD. TESTED TO 900 LB. PER
SQ. FT.]

In another part of this job (the factory annex) where, owing to the open
nature of the structure, it was impossible to house it in as well as the
warehouse