the strength of the hoops after the strength of the concrete between
them has been counted. All the compression of a column must, of
necessity, go through the disk of concrete between the two hoops (and
the longitudinal steel). No additional strength in the hoops can affect
the strength of this disk, with a given spacing of the hoops. It is true
that shorter disks will have more strength, but this is a matter of the
spacing of the hoops and not of their sectional area, as the above
quotation would make it appear.

Besides being false theoretically, this method of investing phantom
columns with real strength is wofully lacking in practical foundation.
Even the assumption of reinforcing value to the longitudinal steel rods
is not at all borne out in tests. Designers add enormously to the
calculated strength of concrete columns when they insert some
longitudinal rods. It appears to be the rule that real columns are
weakened by the very means which these designers invest with reinforcing
properties. Whether or not it is the rule, the mere fact that many tests
have shown these so-called reinforced concrete columns to be weaker than
similar plain concrete columns is amply sufficient to condemn the
practice of assuming strength which may not exist. Of all parts of a
building, the columns are the most vital. The failure of one column
will, in all probability, carry with it many others stronger than
itself, whereas a weak and failing slab or beam does not put an extra
load and shock on the neighboring parts of a structure.

In Bulletin No. 10 of the University of Illinois Experiment Station,[C]
a plain concrete column, 9 by 9 in. by 12 ft., stood an ultimate
crushing load of 2,004 lb. per sq. in. Column 2, identical in size, and
having four 5/8-in. rods embedded in the concrete, stood 1,557 lb. per
sq. in. So much for longitudinal rods without hoops. This is not an