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The Structural Engineer

It is well known that the loading of certain -materials produces not only an initial and immediate strain, but also a further deformation which continues to increase with t'ime, although the applied load is unaltered. Just as a block of pitch flows continuously under the action of a load which may be merely its own weight, so, in varying degrees of magnitude, is the phenomenon noticeable in other materials such as cement, concrete, stone and wood, when they are maintained under constant load. F.G. Thomas

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The Structural Engineer

The CHAIRMAN (Mr. Ewart S . Andrews, Vice- President) said that seldom had the work described in a paper been so well illustrated as in this case by lantern slides. He suggested that speakers in the discussion might with advantage express their views as to the manner in which one could calculate the resistance to an anchor block such as was shown in the type B construction referred to in the paper, to which anchor block the large tension rods were attached.

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The Structural Engineer

My remarks will be confined to a subject which touches us all very closely, namely, the prevailing condition of depression, and the specious cure of which we have heard so much- “Economy.” That fine old word, meaning "the rule (or law) of the house,” or, more generally, just “management,” has suffered an almost complete inversion of its true meaning during the past year or so, and is now understood to mean simply "refraining from spending.” Much as I dislike being a party to the misuse of words, I use it in that sense, because it is the only sense in which it is now used, and to do otherwise would result in being misunderstood. To come straight to my point, I believe that true economy lies not in refraining from spending, but in refraining from borrowing. Our present troubles are not due to excessive spending in the past, but to excessive borrowing. Unfortunately, so far as expenditure upon public works is concerned, we have acquired a habit of thought, by which we assume that spending is inseparable from borrowing, and it is my own firm conviction that while much may be done, and is being done, to restore the prosperity of the country, all such efforts will be brought to nought unless we rid ourselves of this fallacy. It is far from my intention to suggest that public expenditure should never be met by means of loans, but it should be the exception, and not, as at present, the rule. A Local Authority decides to build a new City Hall, or carry out a new sewerage scheme, and for such projects borrowing is both just and unavoidable, but even for such as these I am going to suggest that there should be some adjustment of the amount borrowed and the amount paid “on the nail.’’ The argument advanced in justification of borrowing is that future generations will enjoy the benefit, and should bear an equal share of the cost, but the defect in this argument is that it ignores one benefit which future generations will not enjoy, namely, the benefit of the scheme as a means of relieving unemployment during its construction. This applies to public works of every kind, to some more than others, but with the greatest force to those which are undertaken partly or wholly for the relief of unemployment. Unemployment is a disease of the present, and its cost should be paid in the present, not left for future generations to bear, in addition to their own burdens. Gower B.R. Pimm

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Author – Pimm, Gower B R

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The Structural Engineer

SIR,-. Kent’s comments relating to my communication on “Dynamic Effects in Railway Bridges," published in the November number of The Structural Engineer, are very much to the point, but I think he is perhaps unduly pessimistic. There is no getting away from the fact that the state of oscillation in a bridge, when synchronism is encountered, is governed to a large extent by those somewhat elusive characteristics, damping in the bridge and damping in the spring movement of the locomotive; but it should not be impossible to assign numerical values to the coefficients prescribing those characteristics with a degree of accuracy sufficient for all practical purposes.

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The Structural Engineer

It is no exaggeration to say that the success of reinforced concrete as a structural material has depended very largely on the ability of concrete to adjust itself to stress conditions by means of creep. Scattered through the literature of reinforced concrete we find reference to this power of self -adjustment from the very early days of reinforced concrete construction, but it is only comparatively recently that the mechanism by which it operates has been investigated sufficiently to enable us to predict the progressive stress changes with some semblance of accuracy. It may well be suggested that this investigation, involving as it does all the factors producing progressive volume and length changes in concrete, has done more to extend our knowledge of the behaviour of reinforced concrete than anything else during the last decade. As a consequence, those who have studied these changes have learned to regard the assumptions we have to make in order to produce designs within a reasonable period from a new angle, and to realise that, although they serve reasonably well as a means to an end, they result in computed stresses that are, in general, very different from the actual stresses. W.H. Glanville

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Author – Glanville, W H;Thomas, F G

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The Structural Engineer

WHEN the fist oil well was sunk by Col. Edwin L. Drake in 1859, the chief aim of the oil refiners from then until the late nineties, when the automobile made its appearance, was the production of paraffin or lamp oil, and all the by-products were surreptitiously emptied into any near-by creek or river, as being the easiest way of disposing of this residue, which was of no apparent use. George Noble

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Author – Noble, George

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The Structural Engineer

DURING the last few years the term "Stadia" has frequently been used in describing sports enclosures. It is derived from the old Greek word " Stadium," which originally applied to the foot race course at Olympia. This structure was erected in the 3rd century, B.C., and was 630 feet in length, with two parallel tiers of stone seats along each side, joined at one end by a semicircular curve. It is interesting to note that the distance between the two end pylons measured 606.75 feet, and that this was afterwards adopted by the Romans as a measure of distance, eight "Stadia" being equal to one Roman Mile. James Reed

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Author – Reed, James

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