mentioned in
the author's first point.

It appears to the writer that this fault may be aggravated in the case
of beams with top reinforcement for compression; this is scarcely
touched on by the author. In such a case the top and bottom chords are
of steel, with a weakly connected web system which, in practice, is
usually composed of stirrup rods looped around the principal bars and
held in position by the concrete which they are supposed to strengthen.

While on this phase of the subject, it may be proper to call attention
to the fact that the Progress Report of the Special Committee on
Concrete and Reinforced Concrete[E] may well be criticised for its scant
attention to the case of beams reinforced on the compression side. No
limitations are specified for the guidance of the designer, but approval
is given to loading the steel with its full share of top-chord
stress.[F]

In certain systems of reinforcement now in use, such as the Kahn and
Cummings systems, the need for connections between the web system and
the chord member is met to some degree, as is generally known. On the
other hand, however, these systems do not provide for such intensity of
pressure on the concrete at the points of connection as must occur by
the author's demonstration in his first point. The author's criticisms
on some other points would also apply to such systems, and it is not
necessary to state that one weak detail will limit the strength of the
truss.

The author has only condemnation for the use of longitudinal rods in
concrete columns (Point 15). It would seem that if the longitudinal bars
are to carry a part of the load they must be supported laterally by the
concrete, and, as before, in the beam, it may be likened to a framed
structure in which the web system is formed of concrete alone, or of a
framework of poorly connected members, and the concrete and steel must
give mutual support in a way not easy to analyze. It is scarcely
surprising that the strength of such a structure is sometimes less than
that shown by concrete alone.

In the Minneapolis tests, quoted by the author, there are certain points
which should be noted, in fairness to columns reinforced longitudinally.
Only four columns thus reinforced failed below the strength shown by
concrete alone, and these were from 52 to 63 days old only, while the
plain concrete was 98 days old. There was nothing to hold the rods in
place in these four columns except the concrete and t