An Elementary Course of Civil Engineering for the Use of Cadets of the United States' Military Academy

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Wiley, 1852 - 391 páginas
 

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Página 285 - These means will be amply sufficient to protect the side slopes from injury when they are not exposed to any other causes of deterioration than the wash of the rain, and the action of frost on the ordinary moisture retained by the soil. The side slopes form usually an unbroken surface from the foot to the top. But in deep excavations, and particularly in soils liable to slips, they...
Página 296 - The base of each block should not measure more than five inches, and the top not loss than four inches. The blocks are set by the hand, with great care, as closely in contact at their bases as practicable ; and blocks of a suitable size are selected to give the surface of the pavement a slightly convex shape from the centre outwards. The spaces between the blocks are filled with clippings of stone compactly set with a small hammer.
Página 281 - The gradients should in all cases be reduced as far as practicable, as the extra exertion that a horse must put forth in overcoming heavy gradients is very considerable ; they should, as a general rule, therefore, be kept as low at least as 1 in 33, wherever the ground will admit of it.
Página 335 - If the level of the canal and brook is nearly the same, it will then be necessary to make the culvert in the shape of an inverted syphon, and it is therefore termed a broken-back culvert. If the water of the brook is generally limpid, and its current gentle, it may, in the last case, be received into the canal. The communication of the brook, or feeder, with the canal, should be so arranged that the water may be shut off, or let in at pleasure, in any quantity desired. For this purpose a cut is made...
Página 83 - A long, uniform, cast-iron pillar, with its ends firmly fixed, whether by means of discs or otherwise, has the same power to resist breaking as a pillar of the same diameter, and half the length, with the ends rounded or turned so that the force would pass through the axis.
Página 288 - In side-formings along a natural surface of great inclination, the method of construction just explained will not be sufficiently secure; sustaining-walls must be substituted for the side slopes, both of the excavations and embankments. These walls may be made simply of dry stone, when the stone can be procured in blocks of sufficient size to render this kind of construction of sufficient stability to resist the pressure of the earth. But when the blocks of stone do not offer this security, they...
Página 61 - ... in contact with iron, protects it as fully as zinc alone, and suffers but little loss from the electro-chemical action ; thus presenting a protective energy more permanent and invariable than that of zinc, and giving a nearer approximation to the solution of the problem, " to obtain a mode of electro-chemical protection such, that while the iron shall be preserved the protector shall not be acted on, and whose protection shall be invariable.
Página 326 - In extensive reservoirs, in which a large surface is exposed to the action of the winds, waves might be forced over the top of the dam, and subject it to danger ; in such cases the precaution should be taken of placing a parapet wall towards the outer edge of the top of the dam, and facing the top throughout with flat stones laid in mortar.
Página 8 - Slate. This stone resembles mica slate, being an aggregation of quartz and talc. It is applied to the same purposes as mica slate. 16. Sand-stone. This stone consists of grains of silicious sand, arising from the disintegration of silicious rocks, which are united by some natural cement, generally of an argillaceous or a silicious character. The strength, hardness, and durability of sand-stone vary between very wide limits. Some varieties being little inferior to good granite, as a building stone,...
Página 367 - BO laid as to break joints with the other ; and to prevent the ends of the sills from yielding the usual precaution is taken to place short sills at the joints, either beneath the main sills, or on the same level with them. The boards are laid perpendicular to the axis of the road, experience having shown that this position is as favorable to their wear and tear as any other, and is otherwise the most economical.

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