The theory, practice, and architecture of bridges of stone, iron, timber, and wire: with examples on the principle of suspension

الغلاف الأمامي
John Weale
J.Weale, 1856
 

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الصفحة 94 - In case the contractor shall refuse or neglect to perform the (aforesaid) works, or any of them, in manner hereinbefore in the said specification mentioned, or to obey and comply with any orders or directions to be given by the engineer, or in case at any time during the progress of the works there shall appear to the engineer to be any unnecessary delay in the carrying on of the works, or any part thereof, either by not employing a sufficient number of workmen, or otherwise howsoever, or in case...
الصفحة xv - Bv warrant No. 64 do 65 do 66 do 67 do 68 do 69 do 70 do 71 do 72 do 73 do 74 do 75 do 76 do 77 do 78 do 79 do 80 do 81 do...
الصفحة 22 - In other cases of arches where sandstones, such as Bramley Fall and Whitby, were employed, and their beds faced and dressed as usual, the angle of gliding was found to vary from 35° to 36°. But with m'ortar interposed, the angle generally varied from 33° to 34°. It results from these and other experiments, that friction, by absorbing part of the horizontal thrust, is a most powerful assistant in maintaining the equilibrium of arches, and enables us to determine with something like precision the...
الصفحة 65 - ... built so as to support the arch. If 2 K2--11832r2=0, or K='243r, then in either case the pier may be built to any height whatever, without being overthrown. In this case the breadth of the pier will be nearly equal to £th of the span. The dotted lines in the figure show the dimensions of such a pier. The height of the pier being given, (as is commonly the case,) its breadth, so that the arch may just stand firmly upon it, may readily be determined. As an example, let us suppose the height of...
الصفحة 1 - STONES.* A STRUCTURE may yield, under the pressures to which it is subjected, either by the slipping of certain of its surfaces of contact upon one another, or by their turning over upon the edges of one another ; and these two conditions involve the whole question of its stability.
الصفحة 17 - I may make the direction of the line of resistance or pressure and the form of the bounding surface subject to certain conditions not absolutely determining either. For instance, if the form of the intrados of an arch be given, and the direction of the intersecting plane be always perpendicular to it, and if I suppose the line of pressure to intersect this plane always at the same given angle with the perpendicular to it, so that the tendency of the pressure to thrust each from its place may be the...
الصفحة 3 - MN of any section of the mass in a point n without the surface of the mass, then the resultant of the pressures upon the mass CMN will act through n, and cause this portion of the mass to revolve about the nearest point N of the intersection of the surface of section MN with the surface of the structure.
الصفحة 4 - MN, with the surface of the structure. Thus, then, it is a condition of the equilibrium that the line of resistance shall intersect the common surface of contact of each two contiguous portions of the structure, actually within the mass of the structure ; or, in other words, that it shall actually go through each joint of the structure, avoiding none ; this condition being necessary, that no two portions of the structure may revolve on the edges of their common surface of contact. THE LINE OF PRESSURE.
الصفحة 61 - Although a true mathematical adjustment of the surfaces of the voussoirs to one another can have no existence in practice when the voussoirs are put together without cement, yet may it obtain in the cemented arch. The cement, by reason of its yielding qualities when fresh, is made to enter into so intimate a contact with the surfaces of the stones between which it is interposed, that it takes when dry, in respect to each joint, (abstraction being made of its adhesive properties,) the character of...
الصفحة 3 - ... mass to revolve upon the edge 1. The resultant having the direction a A, the mass will not be made to revolve on either edge of the surface of contact 1, 2. Thus the condition that no two parts of the mass should be made by the insistent pressures to turn over upon the edge of their common surface of contact is involved in this other, that the direction of the resultant, taken in respect to every position of the intersecting surface, shall intersect that surface actually within the mass of the...

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