Examinations July 1969

Mr. James Stevenson of Paisley and six colleagues at a College of Further Education commented that 'Change to Metric' lacked clarity in dealing with mass and weight; they conceded that the Imperial and metric systems confuse unit mass with unit force, 1 Ib with 1 Ibf and 1 kg with 1 kgf and that this results in misunderstandings during the analysis of problems involving both quantity and weight. The SI system, they point out, clearly differentiates between mass and force (as the author explained) but in the final paragraph on p. 335 the author mixed them up. Weight, they say, is a specific type of force and thus must always be quoted in Newtons; the same argument must also be applied to loads, whether gravity loads, dead loads or wind loads.

A series of tests is reported on 40 beams in which the total amount of steel and the amount pre-stressed was varied. Most of the beams were reinforced and pre-stressed with 5 mm (0.2 in) diameter wires, while there were a few tests of beams with pre-tensioned strand and beams with post-tensioned wires. The programme included tests under short-term, sustained and repeated loading. The results are used to analyse the stress in the tensioned and untensioned steel and to consider the factors affecting the flexural strength, crack width and deflection in order to make tentative recommendations for limit state calculations. E.W. Bennett and N.J. Dave

‘In 1919, 50 years ago, Ewart Andrews set up his private practice in London, as Consulting Engineer; I count myself most fortunate to have been one of his partners, and, now, very humble to succeed, after 35 years, such a one as he, and, after 10 years, such a one as my friend and present partner Lewis Kent, as President of this very fine Institution. To these two eminent structural engineers particularly, I owe my thanks: for their friendship, for their guidance and for their support, during almost 40 years in which I have been connected with engineering, of one sort or another.' C.B. Stone