re by tension in the steel is an ideal failure, because it is
easiest to provide against. Failures by slipping of bars, and by
cracking and disintegrating of the concrete beam near the support, as
exhibited by the other tests, indicate danger, and demand much larger
factors of safety.

Professor Clifford, in criticizing the statement that a member which
cannot act until failure has started is not a proper element of design,
refers to another statement by the writer, namely, "The steel in the
tension side of the beam should be considered as taking all the
tension." He states that this cannot take place until the concrete has
failed in tension at this point. The tension side of a beam will stretch
out a measurable amount under load. The stretching out of the beam
vertically, alongside of a stirrup, would be exceedingly minute, if no
cracks occurred in the beam.

Mr. Mensch says that "the stresses involved are mostly secondary." He
compares them to web stresses in a plate girder, which can scarcely be
called secondary. Furthermore, those stresses are carefully worked out
and abundantly provided for in any good design. To give an example of
how a plate girder might be designed: Many plate girders have rivets in
the flanges, spaced 6 in. apart near the supports, that is, girders
designed with no regard to good practice. These girders, perhaps, need
twice as many rivets near the ends, according to good and acceptable
practice, which is also rational practice. The girders stand up and
perform their office. It is doubtful whether they would fail in these
rivet lines in a test to destruction; but a reasonable analysis shows
that these rivets are needed, and no good engineer would ignore this
rule of design or claim that it should be discarded because the girders
do their work anyway. There are many things about structures, as every
engineer who has examined many of those erected without engineering
supervision can testify, which are bad, but not quite bad enough to be
cause for condemnation. Not many years ago the writer ordered
reinforcement in a structure designed by one of the best structural
engineers in the United States, because the floor-beams had sharp bends
in the flange angles. This is not a secondary matter, and sharp bends in
reinforcing rods are not a secondary matter. No amount of analysis can
show that these rods or flange angles will perform their full duty.
Something else must be overstressed, and herein is a v