Report on a Series of Tests on Concrete Columns Reinforced with a Spiral of Steel

In 1907-08 the writers were designing some structures in which certain columns were required to carry heavy loads and would be subjected to considerable shock. The nature of the structures was such that columns of reinforced concrete offered certain advantages, sufficient in importance to warrant the use of that material, even though low stresses and consequently an excessive quantity of material might be required to insure safety. At about this time a number of failures of reinforced columns in important structures at various places in the United States were reported in the engineering journals, sounding a warning against a too liberal estimate of their strength, and plainly indicating the need of a careful study of such members from the experimental standpoint as a basis for safe design.