The Effect of Plastic Yield in Bending on Mild Steel Plate Girders

The prestressing of steel lattice girders has been done in the past by Professor Magnel and by F. J. Samuely. The method used by Professor Magnel is to keep straight or curved high tensile wires within the depth of the girder. The main advantage being that, for a given load high tensile wires are cheaper than mild steel. If the prestressing device is kept within the depth of the girder it is not possible to develop tension in either of the booms due to this prestressing. If the prestressing device is brought below the bottom chord (assuming the girder is to take vertical loading) then the bottom chord is put into compression and the top chord into tension by the prestressing. R. A. Sefton Jenkins

Mr. J. E. SWINDLEHURST (President, British Section of the Societe des Ingenieurs Civils de France; Past-President, Institution of Structural Engineers), introducing the Lecturer, said M. Lazard was a pupil of the Ecole Polytechnique from 1928-1930 and entered the service of Ponts et Chaussees in November, 1933. As an Area Engineer he was responsible for all National and Departmental Road Services in the Department of the Moselle up to the declaration of war, and in 1940 was engaged in a similar capacity on National Roads and the Canal Service in the Department of the Loire.