A Note on the Problem of Rapid Design of Multi-Storey Frames

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

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