Added to basket

Contents page

The Structural Engineer

The World's production of Portland and other Building Cements is estimated to be about 58,000,000 tons per annum; of this total Europe is responsible for about 26,000,000 tons, North America for nearly 28,000,000 tons, and Asia for about 2,500,000 tons. M.E. Day

Publish Date - N/A

The Structural Engineer

8eaham Harbour is situated on the Durham coast about five miles south of Sunderland. Alan Moncrieff

Publish Date - N/A

The Structural Engineer

To the Editor of The Structural Engineer. Sir, I have had occasion quite recently, to discuss with the Manager of a small engineering works, the matter of welding mild steel rods and upon asking him "Can you guarantee your weld?" he retorted by asking "Can you guarantee your steel?" Although the steel rods I was about to have welded were of British manufactsure I could not, of course, guarantee them, nor did I think that, there was any particular merit in the question, until I got a rude shock from my friend (who, by the way, comes from Glasgow, and has had a large experience in engineering and workshop practice) when he explained to me his experience at various times, and even within the past few weeks, of the behaviour of mild steel rods. My reference to welding applies to open forge-welding and rods mean rods foreinforced concrete purposes. I have always held the view that a weld, however carefully forged, could not be as strong as an original rolled rod, arguing by analogy, that, a broken limb, however well set, could not equal in efficiency and strength, the unbroken limb. My concern is not with the strength of welds, but, in arguing the merit and de-merits of welds, my friend was able to point out to me the extraordinary behaviour of round mild steel rods when being bent into truss units. Imagine an ordinary truss, some 25 ft. long of 1 in. section, which, after being bent had become slightly distorted, a very frequent happening. The truss was placed upon an anvil and three blows struck with a 14 lb. sledge-hammer. At the third blow, struck at one end of the rod, the bent portion at the other end dropped off. The diagram shows the relative position of the blow, which was merely a moderate one, and the portion of the rod that dropped off. I was shown the piece (12 in. long) that dropped off, and my friend put it through a severe practical test.

Publish Date - N/A

The Structural Engineer

LT. COLONEL J. MITCHELL MONCRIEFF, C.B.E. (vice President) proposed a hearty vote of thanks to Mr. Digby for his extremely interesting and valuable paper. In the course of his remarks he recalled a conversation he had had with the late Sir Benjamin Baker in about 1896 or 1897, when the Central London Tube Railway was being built. Sir Benjamin had said that he had had the greatest difficulty with vibration: he had thought he had got the thing absolutely like a bed, but, when he went to his club some of his friends, who happened to live over the tube, wanted to know why their china was cracking and their pictures falling. That emphasised the great importance of vibration. Col. Moncrieff also recalled that some years ago he had heen concerned with the building of a chimney about 160 ft. high, and on one occasion happened to be on the platform at the top during a high storm. It was a weird experience to feel the chimney suddenly sway to one side, hesitate, and then come back to the other side, and so on. That was another form of vibration, however.

Publish Date - N/A

The Structural Engineer

WEe come now to study a branch of the subject which usually presents difficulty and the failure to understand which has been a common cause of accidents in the past; the mattter is of great importance from the point of view of public safety because the so-called shear failures occur suddenly without warning, whereas a failure due to ordinary bending always gives warning by excessive deflection. Ewart S. Andrews

Publish Date - N/A

The Structural Engineer

WHEN we speak of the industrial age we generally refer to a period which began about 75 years ago when scientific invention suddenly made great strides and through its agency there was effected that enormous change in our physical environment and economic circumstances which is described as “the industrial revolution.” We now know that the industrial age was not the unqualified success which at one period it proclaimed itself to be. Industrialism has been found to possess blemishes, and the age in which it firm made its appearance now seems to us to be a one-sided age. Certain aspects of man’s nature and certain activities of which he is capable were then given too large a place, with the result that various other elements of human nature were denied their proper scope. Yet, if one were to take one’s opinions from numerous scientific and quasi-scientific writers of the present day one would conclude that the industrial age is going on and on and that we are destined to become still more industrialised, still more completely under the dominion of the machine and of the intellectual standards which the machine-maker is supposed to uphold. There is, however, considerable evidence of the reverse tendency and it may be contended with some show of reason that “ the industrial age ” is passing away. What kind of age then are we approaching? I may perhaps be asked. To which I reply that we are now on the threshold of a period in which the aesthetic side of man’s nature wil1 once more reassert itself to such an extent that we shall witness another of the great formative periods of artistic development which history shows at certain rare intervals-Fifty years ago the results of scientific invention were still so novel that there was an excuse for men to be overborne by the spectacle of such new-found mastery over the mechanical forces of nature, but to-day we have to a certain extent become sated with these inventions, and while we respect inventors we no longer regard them as heaven-sent leaders possessed of the power to direct the course of our civilisation. Moreover, we recognise through bitter experience that while in their use and adaptation these inventions have added to our lives certain comforts and conveniences which we would not willingly forego, they have also brought into the world a great deal of ugliness. A. Trystan Edwards

Publish Date - N/A