Tubular and Other Iron Girder Bridges: Particularly Describing the Britannia and Conway Tubular Bridges; with a Sketch of Iron Bridges and Illustrations of the Application of Malleable Iron to the Art of Bridge-building. With Wood Engravings

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John Weale, 1850 - 132 من الصفحات
 

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الصفحة 81 - Ibs. — 8-2566 tons. This is, however, much below the value which some of my own experiments give, as will be seen further on. The value of/, which represents the strain upon the top or bottom of the tube when it gives way, is the quantity per square inch which the material will bear either before it becomes crushed at the top side or torn asunder at the bottom. But it has been mentioned before, that thin sheets of iron take a corrugated...
الصفحة 51 - Immediately on opening the suspension bridge for railway traffic, the undulations into which the roadway was thrown, by the inevitable unequal distribution of the weights of the train upon it, were such as to threaten the instant downfall of the whole structure.
الصفحة 71 - It will be observed that the whole of these experiments indicated weakness on the top side of the tube, which, in almost every case, was greatly distorted by the force of compression acting in that direction. It is probable that those of the cylindrical form would have yielded in like manner, had the riveting at the joints been equally perfect on the lower side of the tube. This was not, however, the case, and hence arise the causes of rupture at that part.
الصفحة 83 - ... of tubes precisely similar to other tubes fixed on, — but proportionately less than the former in all their dimensions, as length, breadth, depth, and thickness, — in order to enable us to reason, as to strength from one size to another, with more certainty than hitherto, as mentioned before. Another object, not far pursued, was to seek for the proper proportion of metal in the top and bottom of the tube. Much more is required in this direction. In the three series of experiments made the...
الصفحة 45 - Mawr are of a bold and costly construction. The precipitous face of this mountain descends to the water's edge, forming a cliff of steep and rugged outline ; and Telford's work in forming his road at this point consisted of rock-cutting, over a length of 1 mile and 231 yards, and, in some parts, 30 feet in height. This is protected with high breast and retaining walls, having stone parapets laid in lime mortar. The roadway is formed of pavement bottoming and a coating of broken stone ; " so that...
الصفحة 78 - I am of opinion that the tubes should be made sufficiently strong to sustain not only their own weight, but in addition to that load, 2,000 tons equally distributed over the surface of the platform, a load ten times greater than they will ever be called upon to support.
الصفحة 76 - Ibs. (the thin plate being uppermost,) it follows precisely the same law as before, and becomes wrinkled with a hummock rising on the top side, so as to render it no longer safe to sustain the load. Take, however, the same tube and reverse it with the thick plate upwards, and you not only straighten the part previously injured, but you increase the resisting power from 6,812 Ibs. to 12,188 Ibs. Let us now examine...
الصفحة 118 - Figs. 1 and 2 represent the frames employed for this purpose. In fig. 1, AA are vertical side frames of cast iron, fitted to the inside of the plates, and bolted to them ; BB are horizontal frames similarly secured, firmly bolted, and closely fitted to the vertical frames ; c shows the manner in which other cross girders were connected with the vertical frames, for the purpose of connecting the chains. In the Conway tubes, two of these lifting frames were used at each end of the tube, one over the...
الصفحة 81 - But it has been mentioned before, that thin sheets of iron take a corrugated form with a much less pressure than would be required to tear them asunder ; and therefore the value of/, as obtained from the preceding experiments, is generally the resistance of the material to crushing, and would have been so in every instance if the plates on the bottom side (subjected to tension) had not been rendered weaker by riveting. The experiments made by myself were directed principally to two objects : —...

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