The Testing of Structures

1. The various analytical methods for determining the stresses in a continuous framework all start from the same assumptions and lead to the same conclusions, the intermediate processes being relatively long or short according to the characteristics of the particu1ar problem involved. The Author has indicated elsewhere the derivation of special methods from the principle of least work (R. l), and has shown that where it can be applied directly the method of analysis by the principle of least work gives results more readily and more simply than is possible by the application of special methods (R. 2,3). In this paper the method of least work is extended to cover all types of frameworks. E.H. Bateman

THE PRESIDENT (Dr. Oscar Faber, O.B.E., M.Inst.C.E.) proposed a hearty vote of thanks to Dr. Evans for his magnificent paper. It contained, he said, a wealth of material, which might be dealt with adequately if it were spread over six lectures and if about twenty meetings were devoted to its discussion. Mr. GOWER B.R. Pimm, M.Inst.C.E. (Member of Council), endorsed the President’s tribute to the excellence of the paper, but admitted that considerable study was necessary in order to digest its contents.

SIR,In the recent paper entitled “Stress Analysis of Modern Structural Frames,” as reported in the September issue of The Structural Engineer, Mr. J.B.M. Hay is to be congratulated upon bringing up the question of the direct design of indeterminate structures. Most engineers are familiar with the difficulties of mathematical analysis, some of which Mr. Hay pointed out, but rarely is there an exposition of a method of direct design such as that given in the first paragraph of page 392.