Some applications of theory to the practice of construction; a part of the course of instruction at the School of military engineering, Chatham

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Página 128 - In a wrought-iron or steel bridge the greatest load which can be brought upon it, added to the weight of the super-structure, should not produce a greater strain on any part of the material than five tons, where wrought-iron is used, or six tons and a half, where steel is employed, per square inch.
Página 280 - In order that this principle may be fulfilled, the line of resistance should not deviate from the middle of the thickness of the wall to an extent materially exceeding one-sixth of the thickness. In other words, the lines of resistance, when the reservoir is empty and full, respectively, should both lie within, or but a small distance beyond, the middle third of the thickness of the wall.
Página 127 - ... inches above the rails, and the level of the upper parts of the highest carriage doors. This applies to all arches, abutments, piers, supports, girders, tunnels, bridges, roofs, walls, posts, tanks, signals, fences, and other works, and to all projections at the side of a railway constructed to any gauge.
Página 93 - ... 2. To place each abutting surface in a joint as nearly as possible perpendicular to the pressure which it has to transmit. 3. To proportion the area of each surface to the pressure which it has to bear, so that the timber may be safe against injury under the heaviest load which occurs in practice, and to form and fit every pair of such surfaces accurately, in order to distribute the stress uniformly.
Página 204 - If any number of forces, acting on a particle, be represented in magnitude and direction by the sides of a polygon taken...
Página 302 - The best course in practice is to assume a depth for the keystone according to an empirical rule, founded on dimensions of good existing examples of bridges. The following is such a rule : — For the depth of the keystone, take a mean proportional between the radius of curvature of the intrados at...
Página 271 - ... 552. Relieving Arches. In extreme cases, the pressure of the earth may be sustained by relieving-arches. These consist of a row of arches having their axes and the faces of their piers at right angles to the face of a bank of earth. There may be either a single row of them or several tiers; and their front ends may be closed by a vertical wall, — which then presents the appearance of a retaining wall, although the length of the archways is such as to prevent the earth from abutting against...
Página 317 - ... an inch. The portion of plate tested, for both hot and cold tests, is to be 4 feet in length, across the grain, and the full width of the plate, with the grain. The plate should be bent at a distance of from 3 to 6 inches from the edge.
Página 280 - French authors — viz., that there ought to be no pracnvoWed?11 *° b° tically appreciable tension at any point of the masonry, whether at the outer face when the reservoir is empty, or at the inner face when the reservoir is full. Experience has shown that in structures of brickwork and masonry that are exposed to the overturning action of forces which fluctuate in amount and direction (as when a factory chimney is exposed to the pressure of the wind), the tendency to give way first shows itself...
Página 317 - All plates of the first-class, i inch thick and under should be of such ductility as to admit of bending hot, without fracture, to the following angles. Lengthways of the grain, 125°; across, 90°.

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