## The Principles of Bridges: Containing the Mathematical Demonstrations of the Properties of the Arches, the Thickness of the Piers, the Force of the Water Against Them, &c. Together with Practical Observations & Directions Drawn from the WholeT. Saint, and sold by J. Wilkie ..., and H. Turpin ..., and by Kincaid and Creech, 1772 - Bridges - 102 pages |

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abscissa absolute force angle arch of equilibration area ADKS bottom breadth caissons catenary center of gravity circle circular arc consequently convenient Corollary correct fluent curve cycloidal distance divide the stream drawn driven efficacious force elliptic arches equal equation equilibrium expence expression extrados F. I. Pts figure floods fluent of xz fluxion foundation given hanches height hence horizontal line intrados jettee krSA last proposition length method middle navigation ordinate orthographic projection parabola parallelogram passage perpendicular pier is built pier when dry piles prop proportion quadrant radius of curvature resist right line river river Tyne Scholium semicircle sides similar triangles sine space span specific gravity stilts streight line supposed tangent tion tivo triangle velocity vertex voussoirs Wherefore

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Page 85 - ... current may flow freely without the interruption of a pier ; and that the two halves of the bridge, by gradually rising from the ends to the middle, may there meet in the highest and largest arch; and also, that by being open in the middle, the eye in viewing it, may look directly through there. When the middle and ends are of different heights, their difference however ought not to be great in proportion to the length, that the ascent and descent may be easy ; and in that case also it is more...

Page 84 - ... the breadth being still more contracted by the piers, this will increase the depth, velocity, and fall of the water under the arches, and endanger the whole bridge and navigation. There ought to be an uneven number of arches, or an even number of piers ; both...

Page i - The Principles of Bridges ; containing the mathematical demonstrations of the properties of the arches, the thickness of the piers, the force of the water against them, &c. together with practical observations and directions drawn from the whole.

Page 92 - ... river out of its course above the place of the bridge, into a new channel, cut for it near the place where it makes an elbow or turn ; then the piers are built on dry ground, and the water turned into its old course again, the new one being securely banked up.

Page 101 - ... and called a sterling or jettee; after which, loose stones, &c, are thrown or poured down into the space, till it be filled up to the top, by that means forming a kind of pier of rubble or loose work, which is kept together by the sides of the starlings: this is then paved level at the top, and the arches turned upon it.

Page 92 - ... the outer or upper line of the wall above the arch ; but it often means only the upper or exterior curve of the voussoirs. FOUNDATIONS, the bottoms of the piers, &c, or the bases on which they are built. These bottoms are alu-ays to be made with projections, greater or less according to the spaces on which they are built.

Page 81 - ... are also * made either with piles only, driven close by one another, and sometimes notched or dove-tailed into each other, or with piles grooved in the sides, driven in at a distance from one another, and boards let down between them in the grooves.

Page 86 - ... across it, and through the summit of an arch ; and the third also across but taken upon a pier. The elevation is an orthographic projection of one side or face of the bridge, or its appearance as viewed at a distance-, shewing the exterior aspect of the materials, with the manner in which they are disposed, &c.

Page 85 - ... expect to do in looking at it, and without which opening we generally feel a disappointment in viewing it. If the bridge be equally high throughout, the arches, being all of a heignt, are made of one size, which causes a great saving of centering.

Page 88 - Ixittnui level and rightly; for by opening the sluice, the water will rush in and fill it to the height of the exterior water, and the weight of the work already built will sink it; then by shutting the sluice again, and pumping out the water, it will be made to boat again, and the rest of the work may be completed. It must not however be sunk except when the...