Because of the mathematical difficulties which are inherent in problems involving the practical application of the theory of elasticity, a numerical approach towards the solution of these problems has been resorted to. In this paper a method is presented whereby a continuous structure under study is replaced by a lattice structure of equivalent stiffness. The lattice structure is composed of elastic linear members with prescribed stiffnesses, and arranged in specified patterns, according to equations derived by equating the stiffnesses of a lattice element to those of an element of the continuum. The analogue may then be analysed by any large frame computer program; and the results are interpreted to give the stress resultants acting in the continuous structure.
The paper descriptionbed in general outline the planning, contracting and construction of the various structures necessitated by the S.A.R. Adtninistration's decision to double and deviate the Natal main railway line between Umlaas Road and Pentrich.