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

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John Wiley, 1855 - 401 páginas
 

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Página 83 - ... 3d. 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 282 - In the calculations of solid contents required in balancing the excavations and embankments, the most accurate method consists in subdividing the different solids into others' of the most simple geometrical forms, as prisms, prismoids, wedges, and pyramids, whose solidities are readily determined by the ordinary rules for the mensuration of solids. As this process, however, is frequently long and tedious, other methods requiring less time but not so accurate, are generally preferred, as their results...
Página 288 - When the axis of the roadway is laid out on the side slope of a hill, and the road-surface is formed partly by excavating and partly by embanking out, the usual and most simple method is to extend out the embankment gradually along the whole line of excavation. This method is insecure, and no pains therefore should be spared to give the embankment a good footing on the natural surface upon which it rests, particularly at the foot of the slope. For this purpose the natural surface should be cut into...
Página 343 - ... from the usual loads passing over it. The better to secure this uniform distribution of the pressure, the sills of one row are so 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 favourable to their wear and tear as...
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 - ... the other slightly electro-positive, with respect to cast iron. These results will also enable some advances to be made towards the solution of the important problem proposed by the author in his former report, viz., " the obtaining a mode of electro-chemical protection, such that while the metal (iron) shall be preserved, the protector shall not be acted on, and the protection of which shall be invariable.
Página 95 - Note. This last conclusion is drawn from a comparison of the results of experiment with those obtained from calculation, in which the beam is assumed as perfectly elastic. (4-.) " The effect of bodies of different natures striking against a hard, flexible beam, seems to be independent of the elasticities of the bodies, and may be calculated, with trifling error, on a supposition that they are inelastic.
Página 108 - From some quarries the stone may be obtained of any required dimensions ; others, owing to some peculiarity in the formation of the stone, only furnish blocks of small size. Again, the strength of some stones is so great as to admit of their being used in blocks of any size, without danger to the stability of the structure arising from their breaking . others can only be used with safety when the length, breadth, and thickness of the block bear certain relations to each other. No fixed rule can be...
Página 111 - In masses of cut stone exposed to violent shocks, as those of which light-houses, and sea-walls in very exposed positions are formed, the blocks of each course require to be not only very firmly united with each other, but also with the courses above and below them. To effect this, various means have been used. The beds of one course are sometimes arranged with projections (Fig.
Página 100 - It will be found that with the exception of a slight anomaly between 520° and 570°, amounting to — .08, the numbers expressing...

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