The assumption made by the authors that the bolt load produces a uniformly distributed pressure on the outer surface of the plate isuspect, to say the least, and it would have been useful to test this assumption by an analysis of the internal stresses in the bolt head. A study I have made shows that the yield strength of reinforcing steel (i.e. general grade) in Kenya has a coefficient of variation of 17 per cent. Given that this applies also to structural steel, which is fairly certain, could the authors indicate the effect that this would have on their findings? They appear to presume that steel is an exact product. P.A. Campbell
Mr. Johnson: A project such as a float line involves all engineering disciplines with several special branches of these technologies in connection with such items as furnace, float process, etc. Pilkington Brothers Limited have a central engineering department which is responsible on a worldwide basis for the construction and for major repairs of the glass plants of the Group. The resources of this department are augmented from 0utsid.e for such people as consulting engineers, architects, contractors-including specialist contractors for the chimney, structural steelwork, etc.
Why should an engineer today concern himself with the past? Why consider the dead or worry about structural forms that are now outmoded, superseded design methods, or once hallowed assumptions now discarded? Most engineers see themselves as forward-looking people, anxious to be on top of contemporary knowledge and much more interested in what is to come than in what has been left behind.
It seems to me that my professional career has spanned a period of progressive and rapid changes, including as it does the start of the nuclear age, space travel and the second World War and a period, since that war, of development in technologies that has stemmed in large part from the need to defend ourselves. Underlying this need, it appears to me, has been a major increase in speed whether in communications or in weapons which, in turn, has made the reaction time to events as they occur even shorter. Derek R.R. Dick
The paper is concerned with arbitrations and litigation in the construction industry. It outlines the problems of appearing as an expert witness and the difficulties which may occur in the presenting of technical evidence for the consideration and judgement of lay persons. Thomas Akroyd
The application of yield line theory to the ultimate load design of reinforced concrete skew slabs is considered in some detail. With a view to application in highway bridge design, the HA and HB load systems are considered. Bridge slabs with parallel and non-parallel abutments are investigated and the theoretical development is accompanied by the results of a series of experiments on model concrete slabs. K.K. Gangopadhyay and W.M. Jenkins