Author: Gibson, G McLean
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Gibson, G McLean
The Structural Engineer, Volume 9, Issue 3, 1931
PROFESSOR HUSBAND, referring to Mr. Godfrey’s paper “Some New Ideas on Dams” (published in the January issue of The Structural Engineer), said that the opening paragraph made it, clear that the title was a little ironical. Mr. Godfrey stated that so far from the ideas in his paper being in any way new they were very old indeed, but he wished to draw very emphatic attention to them. Many of the members were probably aware that. Mr. Godfrey, who was an eminent consulting engineer in Pittsburg, had for the last 20 or 25 years been carrying on a very intensive campaign against what he called the neglect of the question of up-lift or under-pressure beneath gravity dams. He did not think Mr. Godfrey intended to convey the impression that engineers generally had neglected to recognise the existence or possibility of the existence of up-lift because every engineer understood that it might be present in any dam, but, there was no doubt that in the ease of the earlier dams constructed 40 or 50 years ago, this question of up-lift had been neglected in their design. The dams had not been given a sufficiently large profile in order to guard against the effect of up-lift being exerted beneath their bases. Mr. Godfrey went further and stated that practically all the important dam failures for some years back-and there had been a great many, especially abroad, although we had been particularly immune from them in England, and had been very fortunate in that respect, could be traced to the actions of under-pressure or up-lift. Personally, he believed that Mr. Godfrey in making that statement was practically correct,. At any rate, it could safely be said that about 95 per cent. of the failures were probably due to up-lift. Mr. Godfrey’s arguments about these matters had been, in America especially, very much decried, and he had been denied the opportunity until quite recently of expressing his views before a representative professional audience. It was only within the last 18 months or so that Mr.Godfrey had succeeded in obtaining permission to read a paper on this subject before the American Society of Civil Engineers in New York. Before that paper was read, however, Mr. Godfrey’s agitation had resulted in this question receiving very considerable recognition amongst American engineers and in his own paper Professor Husband said he would show that far from being neglected by British engineers this question of up-lift had been taken into very careful consideration by many of them in the design of important dams. There was no question, continued Professor Husband, that today and for several years past, the question of under-pressure was, and had been receiving very careful consideration in the United States. Since 1916 the United States Bureau of Reclamation-which was the body responsible for the design and building of most of the very large dams in recent years, for irrigation purposes-had been making a very careful series of observations on such important dams
WHEN I was first asked to read a paper this session, I set about trying to find a subject upon which not much had been published widely; I have finished by choosing the subject which has probably been more fully discussed than any other within the range of structural engineering. Ewart S. Andrews
DELEGATES and visitors to the International Congress at Liege last year will be interested in the following particulars of the reconstruction of two famous bridges over the Meuse.