The Torsional Strength of Structural Members Discussion on Paper by Dr. W. B. Dobie

Theoretical and practical considerations are, very often, poles apart. It is important therefore that the engineer should be alert, at all times, to offer evidence to show that his designs are behaving in a manner similar to that assumed when the calculations and detail drawings were being prepared. This article describes the structure of a paper store constructed at Watford for Messrs. Sun Printers, Ltd. The main item of interest in the design is that of the northlight portal frames. The various moments in these were calculated by strain energy methods. The movement of one of the frame legs was computed and deflection tests were carried out by a simple method, during construction. E.F. Whitlam

Summary “Degree of Fixity” methods have been widely developed for application to those cases of rigid frame analysis where sway may be neglected. In this note, the basis of these methods is examined and it is shown that the concept of “equivalent stiffness” is preferable that of “degree of fixity.” By means of this approach the methods are then extended to solve two problems where sway is of importance, namely, wind loading on multi-storey buildings, and continuous beams on elastic supports. R.H. Wood and E. Goodwin

This month's letters cover legislation for design checks, embodied carbon of modular construction approaches, and assessment of masonry buildings for earthquake resilience in New Zealand.