ysically impossible to prevent such vertical steel from taking a
portion of the load unless the steel slips or buckles.

As to the possible danger of the bars in the concrete slipping or
buckling, to which Mr. Godfrey also refers, again must tests be cited.
If the ends are securely held--and this is always the case when bars are
properly butted or are lapped for a sufficient length--they cannot slip.
With reference to buckling, tests have proved conclusively that vertical
bars such as are used in columns, when embedded in concrete, will not
buckle until the elastic limit of the steel is reached, or until the
concrete actually crushes. Beyond these points, of course, neither steel
nor concrete nor any other material is expected to do service.

As proof of this statement, it will be seen, by reference to tests at
the Watertown Arsenal, as recorded in "Tests of Metals," that many of
the columns were made with vertical bar reinforcement having absolutely
no hoops or horizontal steel placed around them. That is, the bars, 8
ft. long, were placed in the four corners of the column--in some tests
only 2 in. from the surface--and held in place simply by the concrete
itself.[S] There was no sign whatever of buckling until the compression
was so great that the elastic limit of the steel was passed, when, of
course, no further strength could be expected from it.

To recapitulate the conclusions reached as a result of a study of the
tests: It is evident that, not only does theory permit the use of
longitudinal bar reinforcement for increasing the strength of concrete
columns, whenever such reinforcement is considered advisable, but that
all the important series of column tests made in the United States to
date show a decisive increase in strength of columns reinforced with
longitudinal steel bars over those which are not reinforced.
Furthermore, as has already been mentioned, without treating the details
of the proof, it can be shown that the tests bear out conclusively the
conservatism of computing the value of the vertical steel bars in
compression by the ordinary formulas based on the ratio of the moduli of
elasticity of steel to concrete.

EDWARD GODFREY, M. AM. SOC. C. E. (by letter).--As was to be expected,
this paper has brought out discussion, some of which is favorable and
flattering; some is in the nature of dust-throwing to obscure the force
of the points made; some would attempt to belittle the importance of
these p