Proceedings of the American Railway Engineering Association Volume 7

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1906 Excerpt: ...line indicating the longitudinal profile of the axis of construction are marked to scale the distances between the various cross-sections and through each point is drawn a perpendicular line. On these perpendiculars are laid off the algebraic sum of the cuts and fills, the cuts being considered as positives and the fills as negatives. When the result is positive the amount is laid off above the horizontal line, and where it is negative the amount is laid off below the horizontal line. By connecting the extremities of the succeeding ordinates by straight lines or parabolic curves, the resulting figure forms what is called Bruckner's curve (Fig. 12). This curve is constructed upon the following assumptions: (1) That each mass of cuts and fills is concentrated on its corresponding point of the longitudinal profile. (2) That on each cross-section only the excesses of the cuts over the fills, or vice versa, are recorded, and consequently the volume of earth transferred from cut to fill by shovel is not considered. Bruckner's curve possesses a number of important properties which may be summarized as follows: (1) The maximum and minimum of the curve correspond to the points at grade where the cut ends and the fill begins, or vice versa; thus the points M and N in the figure are points at grade. (2) The nature of the work is the same in the space between a maximum and a succeeding minimum, and is always cut; it is also the same between a minimum and a succeeding maximum, and is always fill. Thus in the figure the work between A and M is cut, E and F being points at grade. (3) The base-line detaches from the curve segments whose bases represent sections of line in which the cuts and fills are compensated. Thus the cuts equal the ...