THIS paper introduces two new methods of structural analysis for the single-storey, multi-bay frame. The first, the generalized slope-deflection method, is developed from a consideration of the flexural properties of the curved (or bent) structural member. It is, however, restricted in its application here to those “linear” structures in which the connecting eaves joints are only able to rotate and displace horizontally. The second, the generalized moment distribution method, is developed from this first method, and is restricted to the same type of structure. It is based upon the physical conception of allowing the various eaves joints, in turn, both to rotate and displace horizontally together, so that the out-of-balance moments and thrusts are successively eliminated at these joints. E. Lightfoot
DR. W. W. L. CHAN, (Associate-Member) referred to the section given in the paper on Hinge Rotation. Whilst the Author first recognised that Hinge Rotation occurred over a finite length, and was governed by the depth of neutral axis, he then quoted permissible rotations of 0.001 radians and 0.01 radians for unbound and bound sections respectively as being Professor A.I.I,. Haker’s suggested values and used these figures in the worked example of the built-in beam.
M R. K. E. ROWE referred to the Authors’ statement in their introduction that the application of the methods due to Guyon and Massonnet to bridges of longitudinal beams of different section “would undoubtedly bc, very difficult.” This was not the case, for Massonnet1 had shown that if stiffer edge beams are introduced into a bridge grillage, the edge beams having negligible torsional rigidity, then the introduction of shear forces depending on the difference in flexural stiffness between the edge and internal beams yields two simple simultaneous equations for deflexion compatibility from which the deflexion and moment profiles can be obtained. This method had been extended to cover the effect of torsion. Some complexity did arise in this case but with the calculation and presentation in graphical form of the various influence coefficients tlle work could be reduced considerably and should be suitable for design purposes.
ALTHOUGH regulations for the design of structural steelwork specify that girders shall be designed for torsional effects, text books provide no guidance as to the nature of the effects, and how they may be calculated. As a result of the Author's study of this subject and the support provided by B.I.S.R.A. full-size and model tests a method of calculation based on the theory of bending and torsion has already been set out in the Author's published papers. This paper, which is the basis of a lecture to the Institution of Structural Engineers, aims at presenting as simply as possible the theory and conclusions from the tests and gives examples of the method of calculation as applied to common types of girders in practice,which are eccentrically loaded. J.S. Terrington
THE European Committee for Concrete first met at Luxembourg on November 23rd, 1953. Subsequent meetings have been held at Fontainebleau, in May 1954, in Madrid, June 1956, and in Rome, April 1957. The initiative and enthusiasm of French engineers brought it into being, particularly M. Balency-Béarn, the first president, M. Esquillan and M. Brice, all leading members of the ‘Chambre Syndicale des Constructeurs en Ciment Armé de France et de l'Union Française.’ Membership of the Committee is limited to three delegates from each country, who should be authorities in the fields of research and design practice. Simplicity of organisation and intimacy of discussion has thereby been achieved. A larger assembly could not hope to debate effectively the complexities of research and design theory, and make progress in drafting agreed conclusions and recommendations. The enthusiasm of the French, as the instigators of the venture, has persisted, and at each meeting no time has been wasted and a concentrated programme of work has been carried through with zest and endurance, sub-committees often working until late at night, in order to reach understanding and agreement. Professor A.L.L. Baker