isolated case, but appears to be the rule; and yet, in reading the
literature on the subject, one would be led to believe that longitudinal
steel rods in a plain concrete column add greatly to the strength of the
column.

A paper, by Mr. M.O. Withey, before the American Society for Testing
Materials, in 1909, gave the results of some tests on concrete-steel and
plain concrete columns. (The term, concrete-steel, is used because this
particular combination is not "reinforced" concrete.) One group of
columns, namely, _W1_ to _W3_, 10-1/2 in. in diameter, 102 in. long, and
circular in shape, stood an average ultimate load of 2,600 lb. per sq.
in. These columns were of plain concrete. Another group, namely, _E1_ to
_E3_, were octagonal in shape, with a short diameter (12 in.), their
length being 120 in. These columns contained nine longitudinal rods, 5/8
in. in diameter, and 1/4-in. steel rings every foot. They stood an
ultimate load averaging 2,438 lb. per sq. in. This is less than the
column with no steel and with practically the same ratio of slenderness.

In some tests on columns made by the Department of Buildings, of
Minneapolis, Minn.[D], Test _A_ was a 9 by 9-in. column, 9 ft. 6 in.
long, with ten longitudinal, round rods, 1/2 in. in diameter, and
1-1/2-in. by 3/16-in. circular bands (having two 1/2-in. rivets in the
splice), spaced 4 in. apart, the circles being 7 in. in diameter. It
carried an ultimate load of 130,000 lb., which is much less than half
"the compressive resistance of a hooped member," worked out according to
the authoritative quotation before given. Another similar column stood a
little more than half that "compressive resistance." Five of the
seventeen tests on the concrete-steel columns, made at Minneapolis,
stood less than the plain concrete columns. So much for the longitudinal
rods, and for hoops which are not close enough to stiffen the rods; and