Discussion The Effect of Plastic Yield in Bending

I want to speak to you about plastic yield in bending of plate web beams in mild steel. A. Lazard

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

This month's letters discuss foundations in shrinkable ground and highlight a survey on structural optimisation in practice.