Refer back to figure 14-31 and take a closelook at the position of the slope stakes. Thehorizontal distance of a slope stake from thecenter line varies, and to determine what it is, youmust know three things.1. The width of the roadbed, including widthsof shoulders and ditches, if any2. The side-slope ratio (expressed in units ofhorizontal run in feet per foot of vertical rise orfall)3. The difference in elevation between thegrade for the road and the point on the naturalground line where the slope stake will be setIn figure 14-37, view A, d is the horizontaldistance from the center line to the slope stake,W/2 is the horizontal distance from the center lineto the top of the slope, h is the difference inelevation between the finished grade and theground at the slope stake, ands is the slope ratio.The product of h x s gives the run of the slope;that is, the horizontal distance the slope covers.The horizontal distance (d) of the slope stake fromthe center line, then, equals the sum of W/2 plushs. For example, suppose that W/2 is 20 ft, h is10 ft, and the bank is a 4:1 slope. ThenandIn practice, you may have to take otherfactors into account, such as transverse slope orthe crossfall of the pavement (sometimes calledthe crown), ditches, and so on. In figure 14-37,view B, for example, there is a crossfall (h=) acrossW/2 so that the run (horizontal distance covered)of the bank (hbs) is the product of s x hb insteadof hs, as in figure 14-31, view A. The crossfallis usually constant and may be obtained from thetypical design sect ion shown on the plans.Figure 14-37, view C, shows a cut section inwhich W/2 varies with crossfall, side slope, ditchdepth, and back slope. For example, assume thatthe distance from the center line to the beginningof the side slope is 20 ft, that the cross fall totals1 ft, that ditch depth is 1.5 ft, and that both theside slope and back slope ratios are 2:1. Thedistance W/2, then,comprises horizontalsegments as follows:1. From the center line to the top of the slopewhich is 20 ftFigure 14-37.-Determining slope stake location (distancefrom center line) for a proposed roadway.2. Then to the ditch flow line, which equalsthe product of slope ratio (2) times ditch depth(1.5), or 3 ft3. Then to the point on the back slope thatis level with the finished center line, which equalsslope ratio (2) times difference in elevation; thatis, crossfall plus ditch depth,The total distance, W/2, then, is the sum ofSLOPE-STAKE PARTY PROCEDURE.—Slope stakes are usually set with an engineer’s orautomatic level, a level rod, and a metallic ornonmetallic tape. In rough terrain, a hand levelis generally used instead of an engineer’s level.14-38

Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business