uired on the subject; it
is known that the method used gives good results, and that is
sufficient."

This is another example of the logic applied to reinforced concrete
design--another dogmatic statement. If these stirrups act like the
verticals in a Howe truss, why is it not possible by analysis to show
that they do? Of course there is no need of special literature on the
subject, if it is the intention to perpetuate this senseless method of
design. No amount of literature can prove that these stirrups act as the
verticals of a Howe truss, for the simple reason that it can be easily
proven that they do not.

Mr. Thacher's criticism of the sixth point is not clear. "All the shear
from the center of the beam up to the bar in question," is what he says
each shear member is designed to take in the common method. The shear of
a beam usually means the sum of the vertical forces in a vertical
section. If he means that the amount of this shear is the load from the
center of the beam to the bar in question, and that shear members are
designed to take this amount of shear, it would be interesting to know
by what interpretation the common method can be made to mean this. The
method referred to is that given in several standard works and in the
Joint Committee Report. The formula in that report for vertical
reinforcement is:

_V_ _s_
_P_ = --------- ,
_j_ _d_

in which _P_ = the stress in a single reinforcing member, _V_ = the
proportion of total shear assumed as carried by the reinforcement, _s_ =
the horizontal spacing of the reinforcing members, and _j d_ = the
effective depth.

Suppose the spacing of shear members is one-half or one-third of the
effective depth, the stress in each member is one-half or one-third of
the "shear assumed to be carried by the reinforcement." Can Mr. Thacher
make anything else out of it? If, as he says, vertical stirrups are
designed to act like the vertical rods in a Howe truss, why are they not
given the stress of the verticals of a Howe truss instead of one-half or
one-third or a less proportion of that stress?

Without meaning to criticize the tests made by Mr. Thaddeus Hyatt on
curved-up rods with nuts and washers, it is true that the results of
many early tests on reinforced concrete are uncertain, because of the
mealy character of the concrete made in the days when "a minimum amount
of water" was the rule. Reinforcement slips in such concrete when it
would