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 EngravingsJohn Weale, 1850 - 132 من الصفحات |
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عبارات ومصطلحات مألوفة
9 inches abutments angle iron Anglesea applied arch arch bridges bar iron beam bolted bottom plates breaking weight Britannia Bridge Britannia tower Britannia Tubular Bridges Caernarvon Caernarvonshire cast cast-iron girder centre chains cohesive power compression connected construction Conway cylinder deflection depth diagonal dimensions ditto engineer equal erected experiments Fairbairn feet 6 inches feet in length feet wide fixed flange force frames girder bridge horizontal hydraulic press inch thick inches wide invention joints lattice bridge lifting load longitudinal main tubes malleable iron masonry material Menai Menai Straits metal nearly patent Penmaen pier pontoons punching rails railway rectangular ribs river Dee rivets road roadway Robert Stephenson rollers scaffolding sectional area side plates span spandrils square inch Stephenson straits strength structure supported suspension bridge T-iron Telford timbers tons top and bottom trussed tubular girders upper vertical width wrought wrought-iron وو
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الصفحة 91 - ... 124 inch— the resistance, per square inch, will be 19'17, 14'47, and 7'74 tons respectively. The breaking weights here employed do not include the pressure from the weight of the beam. " The value of / is usually constant in questions on the strength of bodies of the same nature, and represents the tensile strength of the material ; but it appears from these experiments that it is variable in tubes, and represents their power to resist crippling. It depends upon the thickness of the matter...
الصفحة 89 - 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 : —...
الصفحة 89 - 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 59 - 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 86 - 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 84 - 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 91 - 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 tubes were rectangular, and the dimensions and other values are given below : — The tube placed first in each series, is intended to be proportional in every leading dimension, as distance between supports, breadth, depth, and thickness of metal, — and any variations are allowed for in the computation....
الصفحة 84 - It has invariably been observed, that in almost every experiment the tubes gave evidence of weakness in their powers of resistance on. the top side, to the forces tending to crush them. This was strongly exemplified in experiments 14, 15, 16, &c., marked on the drawings and the table. With tubes of a rectangular shape, having the top side about double the thickness of the bottom, and the sides only half the thickness of the bottom, or one-fourth the thickness of the top, nearly double the strength...