General Description of the Britannia and Conway Tubular Bridges on the Chester & Holyhead Railway

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Chapman and Hall, 1849 - Britannia Bridge (Wales) - 34 pages
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Page 18 - ... finally converted into a rivet, which, by contracting as it cools, binds together the plates even more firmly than they had already been almost cemented by the irresistible coercion of three sledge-hammers; indeed they are so powerfully drawn together, that it has been estimated it would require a force of from four to six tons to each rivet to cause the plates to slide over each other.
Page 14 - This additional length is intended to afford a temporary bearing of 6 feet at each end after they are raised into their places, until there is time to form the connexion between them across the towers. Our London readers will better appreciate the great length of these tubes by remembering, that if one of them were placed on end in St. Paul's Churchyard it would reach 107 feet higher than the top of the cross!
Page 11 - Conway, were furnished by F. Thompson, Esq., of London. When the whole structure is completed, it will consist of two immense wrought-iron tunnels or tubes, each considerably upwards of a quarter of a mile in length, placed side by side, through which the up and down trains respectively will pass. The ends of these tubes rest on abutments, the intermediate portions being supported across the Straits by three massive and lofty stone towers. The centre tower, as has been just observed, stands on a...
Page 8 - ' tubular," for not only are they hollow from end to end, and closed in, all round, in manner of a tube; but further, both their roof and floor are formed of rows of smaller square tubes, side by side, all firmly connected together, adding most materially and essentially to the strength and stiffness of the main body. Indeed, on a close scientific investigation, its whole strength will be found to reside in the cellular structure at the top and bottom. This, which is by far the most original and...
Page 19 - ... by three sets of massive cast-iron beams, placed across the inside of the tube, one above another, their ends fitting under deep shoulders or notches in the lifting frames, where they are secured by screw-bolts ; as an additional security, two very strong wrought-iron straps pass over the upper pair of beams, and descend into the bottom cells beneath the frames, where they are strongly keyed. The weight of these lifting frames and cast-iron...
Page 14 - small tubes,' their span is vastly greater than that of any other railway bridge in existence, the Conway tubes alone excepted. But the large tubes, which are to cross the water, are constructed on timber platforms along the beach, on the Carnarvon shore, just above the level of high water. These have consequently to be removed, and elevated to their final position on the towers ; and to these the principal interest attaches. " The length of one of these tubes, as constructed on the platform, is...
Page 7 - ... strength from any transmission of horizontal pressure to the abutments, such as is given to an. arch; nor from any mode of suspension, as in a chain bridge; but they have power to resist incumbent pressure, on exactly the same principles as the short plank by which the village brook is crossed. Yet their form, and the method of employing the material of which they are composed, are very different from those of a simple beam, or girder. They are tubular, and it is in this peculiarity that their...
Page 23 - Bratnah, and extensively used in this country in expressing oils, packing soft materials, and in many operations where an intense pressure is required. Its construction is so simple that it may be readily understood by any person, however unacquainted with machinery. It consists only of an exceedingly thick and heavy iron cylinder, like a mortar; a strong piston or plunger, also of iron, called the ram, works up and down inside this cylinder, and is fitted with a leather collar at the shoulder, so...
Page 25 - Britannia tower, and act in conjunction. The chains, by which the power exerted by the presses in their lofty position is communicated to the tubes lying at the base of the tower, resemble the chains of an ordinary suspension-bridge, and are very similar in appearance to those of Hungerford Bridge, in London.

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