Optimum Design of Welded Plate Girders

The fairly long discussion which has taken place on trussed rafters, connector plates and associated aspects has brought a fairly vigorous response from Mr. H. J. Andrews in their defence. He writes: I feel the time has come to respond to some of the absurdities that are being quoted in your column 'Queries, Comments, Correspondence and Curiosities' in connection with trussed rafters, and more recently the addition of joist hangers (Sept. 1977). Verulam

There are environmental, technical and commercial reasons why the increased use of lightweight aggregate for concrete should be encouraged in this country. In this paper, arguments in favour of and factors acting against the more general use of the material are examined and it is suggested that a major stumbling block is confusion between straight forward lightweight aggregate concrete suitable for most normal construction and the more exotic materials requiredfor highly specialised applications. The author proposes a new category of lightweight concrete for those mixes that behave like normal dense concrete and argues that they should be exempt from the special restrictions imposed by current Codes of Practice on reinforced lightweight concrete. Examples of the use of both types of lightweight concrete are given together with summaries of cost studies and cost evaluations. M.E.R. Little

To many minds, structural engineering seems to be limited to the conception and analysis and detailed embodiment of structural systems. And there is no doubt that this is the very core of our science. Obviously the art is concerned with the application of the science, but it is also concerned with wider issues; social and political issues such as the particular purpose for which the system is intended, the need for it, the resources which are required to realise it and the consequences of its realisation. And also, even if in self interest, creating a demand for buildings which need the sort of structures which we would like to design. Peter Dunican