Engineering and Contracting . Fig. 1 — Method for Obtaining Controlling Points. Where roadways of different widths Intersect use the proportionfor superelevation of the widest roadway. From the center intersection of the crown centers, to the crowncenter opposite the block corners the grade shall be a straight line,and from any point along this line the lateral grade shall be para-bolic to the curving crown center line grade. Within the ciown center grade platform the grade shall radiateparabolically from the crown center lines to the sides of the centergrade platform. The one-quarter control
Engineering and Contracting . Fig. 1 — Method for Obtaining Controlling Points. Where roadways of different widths Intersect use the proportionfor superelevation of the widest roadway. From the center intersection of the crown centers, to the crowncenter opposite the block corners the grade shall be a straight line,and from any point along this line the lateral grade shall be para-bolic to the curving crown center line grade. Within the ciown center grade platform the grade shall radiateparabolically from the crown center lines to the sides of the centergrade platform. The one-quarter control point of the center platformshall be obtained by taking one-third of the total fall from the crowncenter intersection to the* gutter line on the center of the respectivecrown center curve and subtracting this from the crown center Fig. 2—Visualization of Controlling Points The grade of the property line or side line of the street shall be astraight line between such points, unless a vertical curve or gradeestablishment inter\-ene between such points, then such property linegrade shall conform to the intervening grade. The lateral grades of the sidewalk area between the curb line andproperty line shall be preferably 2 per cent descending to the optional with the City Engineer to increase lateral grade to 4per cent, opposite block corners, provided the lateral rate of 2 percent is again maintained at a point 12 ft., or in distance three timesthe rate of grade, back from the block centers. For all hard surface pavements the proi?ortion of crown shall in-crease or decrease in the ratio of five-tenths of 1 ft. crown to 36 roadway, and the elevation of the crown be fixed by the elevationof the high gutter line. on 12 Per Cent and 6 Per Cent Grades. The establishment of a grade point on the curb at th
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Keywords: ., bookcentury1900, bookdecade1900, bookpublisherchicago, bookyear19
