Mr. Goodrich says that the writer’s reasoning as to the sixth point is almost wholly facetious and that concrete is very strong in pure shear.  The joke, however, is on the experimenters who have reported concrete very strong in shear.  They have failed to point out that, in every case where great strength in shear is manifested, the concrete is confined laterally or under heavy compression normal to the sheared plane.  Stirrups do not confine concrete in a direction normal to the sheared plane, and they do not increase the compression.  A large number of stirrups laid in herring-bone fashion would confine the concrete across diagonal planes, but such a design would be wasteful, and the common method of spacing the stirrups would not suggest their office in this capacity.

As to the writer’s statements regarding the tests in Bulletin No. 29 of the University of Illinois being misleading, he quotes from that bulletin as follows: 

“Until the concrete web has failed in diagonal tension and diagonal cracks have formed there must be little vertical deformation at the plane of the stirrups, so little that not much stress can have developed in the stirrups.” * * * “It is evident, then, that until the concrete web fails in diagonal tension little stress is taken by the stirrups.” * * * “It seems evident from the tests that the stirrups did not take much stress until after the formation of diagonal cracks.” * * * “It seems evident that there is very little elongation in stirrups until the first diagonal crack forms, and hence that up to this point the concrete takes practically all the diagonal tension.” * * * “Stirrups do not come into action, at least not to any great extent, until the diagonal crack has formed.”

In view of these quotations, the misleading part of the reference to the tests and their conclusion is not so evident.

The practical tests on beams with suspension rods in them, referred to by Mr. Porter, show entirely different results from those mentioned by Mr. Goodrich as being made by Moersch.  Tests on beams of this sort, which are available in America, seem to show excellent results.

Mr. Goodrich is somewhat unjust in attributing failures to designs which are practically in accordance with the suggestions under Point Seven.  In Point Seven the juggling of bending moments is condemned—­it is condemnation of methods of calculating.  Point Seven recommends reinforcing a beam for its simple beam moment.  This is the greatest bending it could possibly receive, and it is inconceivable that failure could be due to this suggestion.  Point Seven recommends a reasonable reinforcement over the support.  This is a matter for the judgment of the designer or a rule in specifications.  Failure could scarcely be attributed to this.  It is the writer’s practice to use reinforcement equal to one-half of the main reinforcement of the beam across the support; it is also his practice to curve up a part of the beam reinforcement and run it into the next span in all beams needing reinforcement for shear; but the paper was not intended to be a treatise on, nor yet a general discussion of, reinforced concrete design.