RAPID design of multi-storey frames has received attention mainly as a result of new techniques, such as limit analysis, electronic and analogue computers, developments in nomography and so on. The elaborate results of present-day research apparently conflict with the stringent demands for rapid design, and it may be helpful in view of correspondence on a previous paper by the author to consider the basic factors that influence the formulation of rapid design methods. R.H. Wood
This paper discusses the application of the simple plastic theory to the design of mild steel Vierendeel girders. Three modes of failure are described and equations are derived for calculating the collapse load of a girder in each of these modes. Experimental results are quoted in confirmation and the application of the analysis to the design of parallel and inclined chord girders is illustrated by calculations for the design of a five panel bridge girder. Arnold W. Hendry
FAILURE of a prestressed concrete beam in bending* is caused initially either by yielding of the steel near the bottom face (Primary tension failure), or by crushing of the concrete near the top face (Primary compression failure). Primary tension failures occur in beams with low steel ratios, whereas primary compression failures are to be expected in heavily reinforced beams; the two types of failure occur simultaneously for a certain limiting steel ratio r'o which depends on the properties of the two materials and the bond between them. Professor Henry J. Cowan