of the T to grip the steel) are the only proper
exemplifications of the "theory of T-beams," it is time for engineers to
ignore theory and resort to rule-of-thumb. It is not theory, however,
which is condemned in the paper, it is complex theory; theory totally
out of harmony with the materials dealt with; theory based on false
assumptions; theory which ignores essentials and magnifies trifles;
theory which, applied to structures which have failed from their own
weight, shows them to be perfectly safe and correct in design;
half-baked theories which arrogate to themselves a monopoly on
rationality.

To return to the spacing of rods in the bottom of a T-beam; the report
of the Joint Committee advocates a horizontal spacing of two and
one-half diameters and a side spacing of two diameters to the surface.
The same report advocates a "clear spacing between two layers of bars of
not less than 1/2 in." Take a T-beam, 11-1/2 in. wide, with two layers
of rods 1 in. square, 4 in each layer. The upper surface of the upper
layer would be 3-1/2 in. above the bottom of the beam. Below this
surface there would be 32 sq. in. of concrete to grip 8 sq. in. of
steel. Does any one seriously contend that this trifling amount of
concrete will grip this large steel area? This is not an extreme case;
it is all too common; and it satisfies the requirements of the Joint
Committee, which includes in its make-up a large number of the
best-known authorities in the United States.

Mr. Thacher says that the writer appears to consider theories for
reinforced concrete beams and slabs as useless refinements. This is not
what the writer intended to show. He meant rather that facts and tests
demonstrate that refinement in reinforced concrete theories is utterly
meaningless. Of course a wonderful agreement between the double-refined
theory and test can generally be effected by "hunching" the modulus of
elasticity to suit. It works both ways, the modulus of elasticity of
concrete being elastic enough to be shifted again to suit the designer's
notion in selecting his reinforcement. All of which is very beautiful,
but it renders standard design impossible.

Mr. Thacher characterizes the writer's method of calculating reinforced
concrete chimneys as rule-of-thumb. This is surprising after what he
says of the methods of designing stirrups. The writer's method would
provide rods to take all the tensile stresses shown to exist by any
analysis; it would give t