Preliminary Survey and Estimates (Paperback)

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. 1900 Excerpt: ...L = length of curve in feet. C _ 50... cos(r), _--i A _ _ L d i 10o We have now sufficient data for ranging a curve. Example i. The intersection point occurred at station 753 + 34 The angle of deflection was 37'916. It is intended to put in a 5 curve. Required, the length of the subtangent, the apex distance, the length of the curve, and the chainage of the B. C. and E. C. points and the apex. The radius of the curve is found from the table p. 411 = 1,146 feet. Subtan = 1,146 x tan 37 91 _ 303-7 2 1146 Apex dist. =-170-73-1,146 = 65-7 feet cos J/ y. Length of curve = 37 9I x 100 = 758-3 feet 0 B. C. point = 753 + 34-393-7 feet = 749 + 40-3 E. C. point = 749 + 4-3 + 758-3 feet = 756 + 98-6 Apex point at 749 + 40-3 + 1$--feet = 753 + 19-9 2 Lay off angle El A Fig. 68= l8oD and measure off IA = 65-7 feet, and put a stake in marked 'Apex, 753 + 19-9.' Measure the subtangent both ways, and put in pegs with nails, aligning them from the transit at the intersection point. Put in reference stakes marked B.C. 749 + 40-3 and E.C. 756 + 98-6. Shift the transit to the B. C. point and commence to range the curve. The first odd distance will be 59-7 feet; the tangential angle for this will be i-x $9--7 = i'49. The 2 IOO instrument is set to read this angle and a stake put in marked 750. The next angle will be 2'5 (2 30') f 1-49 = 3"99, which is set off and a stake aligned and driven at another hundred feet and marked 751, and so on. After stake 753 is driven, at a tangential angle of '8'99 the odd distance, 19-5 to the apex point, is set off, the angle being 2-5 x--5. = o'49, or angle from the beginning 8-99 "IOO +-49 = 9'48. This will be one-half the total tangential angle, or one-quarter of the angle of deflection. Both the odd distances to the apex and to.