Issue 13

A method is presented for the minimum cost design of multistorey rectangular steel frames to limiting values of horizontal sway deflection. The frame is rendered statically determinate by assuming points of contraflexure. Realistic expressions for steelwork cost are obtained in terms of the moments of inertia of the members. These expressions are used, together with slopedeflection analysis, to derive equations for design. The equations are suitable for hand calculations, and their accuracy is found to be good by comparison with computer analysis. Account can be taken of restrictions on section size and change of section, and of the lack of a continuous range of rolled sections. D. Anderson and M.A. Islam

Modified stability functions for uniformly tapered beam-columns having wide flange, box section, and other cross-sectional shapes are developed and tabulated for different values of axial parameters, end depths ratios, and shape factors. They make possible the rapid prediction of the elastic critical load of structures with non-prismatic members, using a hand-computing method. Approximate formulae for the modified stability functions are presented. S. Z. Al-Sarraf

The behaviour of continuous composite beams is examined in terms of the two primary modes of flexural failure, and computer tests simulating beam behaviour are described. Consideration of the behaviour and of the test results has enabled recommendations to be made on the amount of redistribution of moments that can be permitted. The recommendations apply to beams having joists of either 'compact' or 'slender' cross-section and to beams that are designed as either propped or unpropped. An outline design procedure is given. M.C. Hope-Gill

A method is presented to evaluate the response of vertically vibrating machines placed on large, flexible, elastically supported slabs. I. Alpan and D. Leshchinsky