Methods for the Computation from Diagrams of Preliminary and Final Estimates of Railway Earthwork; With Diagrams Giving Quantities on Inspection to the Nearest Cubic Yard, for Both Regular and Irregular Sections, Direct from Ordinary
This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1887 edition. Excerpt: ... cuttings on either side (for the side-heights there is, of course, a cutting only on one side). From the sum of the quantities obtained, deduct that given by entering the diagram with the sum of the side-heights and the sum multiplied by r. Also, for each solid, enter the diagram with the cutting at the apex of each triangular surface-plane and with the length of the base of the triangle in the other end-section. From the sum of the quantities obtained, deduct that given by entering the diagram with the sum of the side-heights of one end-section, and the sum multiplied by r, of the other. Then the total volume of each solid, for a length of 100 feet, is given by adding together the quantities for the end-sections and for the solid. When one end-section is three-level, as must frequently be the case, the quantity for each section obtained as above is equal to the quantity equation (22), + 16.7, the difference between of the solidity of the grade-prism (50 yards), which is actually deducted in equation (21), and of that solidity (66.7 yards), which strict theory requires to be deducted. Also, when Plate X. is in use, by the rule of paragraph 109, for another road-bed than 18 feet, the quantity 8, as taken off must be corrected by two-thirds only of the correction in Table II. (plus 16.7 as before) to have it equal to the quantity obtained as above: For example, if the road-bed be 20 feet, the correction in Table II. ia--70.4; xf=-46.9; +16.7=-30.2. Art. V.--Computing Excavation on Curves. 76. Although the error due to curvature is not commonly of very great moment, it will sometimes reach large dimensions, for the amount of which the following gives some basis of comparison. With a 50 feet centreheight and 15 surface-slope on...
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