This paper describes the development of economical, tapered steel portal frame structures for industrial buildings in the United Kingdom, by a project team consisting of a firm of industrial steel building manufacturers, a consulting engineering partnership, and a university. It discusses the advantages of this structural form, the role of slender webs in the economy of these structures, and the complexities of structural behaviour arising from the slender cross-section. The design method is described, and its experimental verification by full-scale testing is summarised. The paper concludes with a description of the implementation of this new development in the drawing office and fabrication shop, making extensive use of computerisation and automated fabrication techniques. Professor P.J. Dowling, T.F. Mears, G.W. Owens and G.K. Raven
Mr G. E. Bratchell (F) (NCL Consulting Engineers): When the paper ‘Teaching towards an improved understanding of structural behaviour’ appeared in 1977, I felt that the people responsible for teaching engineering were beginning to respond to an undercurrent of concern felt by practitioners (e.g. consulting engineers and contractors) that the products of universities were becoming more highly skilled as analysts but less able to achieve a feeling for general engineering behaviour. The effects of this were the production of structural designs with meticulously designed elements but with a tendency to suffer from weaknesses attributable to lack of understanding of the behaviour of the structure as a whole and, increasingly, the interactive behaviour of the foundation soils and other environmental effects.
The Membership (Part 3) examination papers are set by corporate members with many years' practical experience of structural engineering; the questions themselves are invariably based on actual projects. The work of candidates is marked by younger members who, while having acquired extensive professional experience, can nonetheless remember the trauma of tackling a Part 3 examination question. Both Chief and Marking Examiners hope to award every candidate a passmark, but they are aware of their duty to the Institution and to the public at large. Each knows that a chartered structural engineer must have an ability to design safely and economically and a facility to communicate design intentions. Thus Part 3 questions are framed to give every candidate an opportunity of demonstrating these essentials for a professional career.
Mr Alfred Goldstein (F) (R. Travers Morgan & Partners): As a supporter of the KISS principle (‘keep it simple, stupid’), I can agree with Mr Taylor’s general direction, but I would not go as far as he. I can also agree with Mr Sunley’s view that BSI is trying to do too much. I cannot agree, however, that those drafting these documents should do what is necessary without consideration of the future user.
Purlins . . . again The letters from Messrs Ascough and Millington (April 1982) have brought the following response from Professor A. Bolton: Mr Massey’s December 1981 letter, as you remark, concerned rafters supported on purlins. Mr Peter Ascough says that the solution is very simple-it all depends on the way the seatings are formed-and illustrates his answer by drawings showing rafters supported on wheels. Mr G. S. Millington discusses the reactions supporting the rafter as being all-important. As he says, sometimes the ridge is so flimsy that there is no chance of the reaction there being anything but horizontal, one-half of the roof merely leans on the other. If, however, the ridge is a substantial member, itself supported on cross-walls or other supports, it might provide a vertical reaction at the top of the rafter. Mr Ascough points out that timber shrinks and that the rafter may hang from a purlin or ridge beam or strut up from the wall-plate as the rest of the supports shrink away. Verulam