Response to Response on Viewpoint on We Are Our Future by Mr Cheng Chee Chai

This paper, by Dr. D. T. Yeomans and Dr. D. Cottam, was published in The Structural Engineer, Vol. 67, No. 1O, 16 May 1989, p183 et seq. Dr. J. M. Roberts (M) (Allott & Lomax): The authors’ analysis of the Tecton/Arup collaboration on design of flats makes fascinating reading, the more so because of the lack of similar objective studies. What intrigues me is the basis of their statement that ‘designers are not reliable reporters of their own design processes’, which appears at first sight to be an extraordinary hypothesis. An ‘outsider’s’ analysis of the design that eventually emerges from the complexities of architectural and structural interrelationships could be very misleading, unless the reasoning and constraints that applied during the design evolution were documented adequately enough to allow an independent appraisal.

Tests were carried out on seven full-scale composite columns about 3 m long, representing a typical storey height in multistorey buildings. The columns were made of a concrete-filled rolled steel rectangular hollow section 120 x 80 x 5 RHS. The experimental results are presented here, and are compared against the predictions of a finite element numerical analysis, and also with the failure loads as predicted in accordance with BS 5400 for the design of composite bridges. The tentative conclusions and recommendations given are based on the small number of tests carried out. H. Shakir-Khalil and J. Zeghiche

A basic method for the design of ground-bearing warehouse slabs subjected to point loads is proposed, based on the use of design charts. These charts have been drawn rom the computed results of a truly 3-dimensional analysis, in which both the soil and the slab are treated as behaving elastically. The method utilises plate bending finite elements and a layered continuum model for the soil (Wood'). The method is suitable for use in a design office, allowing consideration of the additional moments imposed under one load by any other point load on the slab. The accuracy of this method is shown to be within 2% of the more rigorous full solution. A. Fatemi-Ardakani, E. Burley and Professor A.L. Wood