Issue 11

For nearly thirty years, including seven years of war-time, I had no contact with the Institution headquarters except by post and through reading-or trying to read-the journal. In early days I knew only one name: Major Maitland, and I wondered but never understood what went on at 'headquarters'. How did 'they' decide whether or not I was to achieve my ambition to become a fully-fledged structural engineer? One realized that Major Maitland did not do all the work himself and that even given a President, elected yearly, the two of them must have a large body of assistance, both from the members themselves and from some sort of secretariat, to handle all the business-not fully understood by me of a major professional institution. Peter S. Rhodes

The reservations that Professor Heyman expresses regarding the relationship of loads assumed in simple plastic design to real states of loading have some justification, particularly in view of the dubious nature of stochastic calculations in relation to extreme loading conditions. I find it, however, more difficult to follow his arguments in relation to deflexions and stability calculations. Professor M.R. Horne

Mr. K. Kretsis (F) : I would like to ask a question with regard to tube combination by internal sub-division. The horizontal beam members of the external tube sides have a considerable stiffness, how is a comparable stiffness achieved in the horizontal beam members of the internal sub-divisions of the tubes so that they may have a substantial effect on the shear lag within the external cross-planes of the tubes?

The history of the Fort Regent from its origins to the present day are first described followed by the requirements of the States of Jersey and the evolution of the design now under construction. The engineering problems encountered and the derivation of design loadings together with the solutions to these problems and the design logic employed are discussed. The various structural elements that form the complete roof structure, such as the curved roof beams, fascia girders, portal frames, and the north and south ends and the dome, are fully described together with the design procedure for the structural elements and the methods of shop and site fabrication. W.H. davies, B.A. Gray and F.E.S. West

Beams of varying depth are widely used in civil engineering structures, and are particularly suitable for large span prestressed concrete bridges. It is well known that the distribution of shear stress and hence principal tensile stress may be considerably affected by the variation in depth. A review is made of the various elastic analytical methods available, and their assumptions are discussed. The accuracy of each analysis is assessed on a plane wedge under separate application of normal force, shear, and bending moment, for a range of slopes and curvatures. The effect of curvature is shown to be unimportant for the values associated with bridges. The approximate forms of the solutions reached by Boussinesq and Wysiatycki are shown to be identical. These expressions are simple and give good agreement with the exact solution. Photo-elastic and finite element models are used to examine the accuracy of the various analytical methods applied to box-sections. Gwynnes Davies, Richard S. Lamb and Cyril Snell

An experimental investigation on reinforced concrete beams undertaken to determine the influence of fluctuation of loading on deflexions is described. The beams were subjected to a range of loading regimes usually with a fluctuating component. A linear logarithmic relationship was found between the increase in maximum deflexion and the number of fluctuations or the length of time under load. Increases in deflexion of beams under fluctuating loads were about the same as for beams subjected to sustained load equal in magnitude to the maximum of the fluctuation. The results are related to present design criteria and methods of analysis for deflexions of reinforced concrete structures and the implications for design are discussed. P.R. Sparks and J.B. Menzies