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SLOPE-STAKE PARTY PROCEDURE. Slope stakes are usually set with an
engineers or automatic level, a
level rod, and a metallic or nonmetallic
tape. In rough terrain, a hand level is
generally used instead of an engineers level. If
the engineers level is used, three crew members are
generally employed for fieldwork; they are the instrumentman,
the rodman, and one person to hold
the zero end of the tape at the center line. When
a hand level is used, two persons can take care
of the jobthe instrumentman also holds the zero
end of the tape and is positioned at the center-line
station as the rod reading is taken. The procedure
followed is a trial and error process. Under
field conditions, the rodman is at times as much
as 200 or 300 ft away from the instrument-man. If
power equipment is operating nearby or a
wind is blowing, oral instructions cannot be given
to the rodman about where to take trials shots;
in fact, often there. is not a clear view of the
ground slope at the station being worked. Consequently, the rodman must know as much as the instrumentman does about the theory and practice of setting slope stakes. The speed and efficiency of the party depend on the rodman more than on any other member. The rodman must be constantly mentally alert.The most practical field procedure requires that the rodman know the value of W/2 and of s (the slope ratio). This is not difficult, since these values are usually constant for several stations, and the rodman can be informed when they change. A typical procedure for setting slope stakes is as follows:1. The instrumentman computes the center-line cut or fill, using the HI, finished grade, and the existing ground elevation. Refer back to figure 14-36.2. The instrumentman calls or signals the center-line cut or fill to the rodman.3. The rodman mentally computes the approximate value of d by multiplying h x s and adding W/2. He pulls the tape taut while holding the tape at the computed distances.4. Noting the approximate rise or fall of the ground, the rodman adjusts the approximate value of d, moves to the d point, and sets up the rod for a trial shot.5. The instrumentman quickly calculates the cut or fill at this point and calls the value to the rodman.6. The rodman compares this with the estimated cut or fill. He should be fairly close and should know at once whether to move toward, or away from, the center line. Having a much shorter distance over which to estimate ground slope, he again estimates new cut or fill and hs + W/2, and moves the rod to the new d value.
Figure 14-38.-Setting slope stakes. 7. The instrumentman again gives the cut or fill; if the value checks, the rodman calls or signals back the cut or fill and the distance.8. The instrumentman quickly checks the two values mentally, and if the values are correct, records the values in the field book, signaling "Good" to the rodman.9. The rodman marks and drives the stake. With practice and on fairly smooth ground, a good rodman will seldom miss the first trial by more than 0.2 ft vertically and will, quite often, hit the correct value on the first trial. Figure 14-38 shows the application of these procedures to an actual situation. The following data are known for this slope-stake stakeout: 1. The station is 15 + 00. 2. The W/2 (from the typical design section) is 20 ft. 3. The slope ratio is 1:1; therefore, s = 1. 4. The existing ground elevation at the center line (from the previously run profile) is 364.00 ft. 5. The HI is determined to be 369.30 ft at that setup. |
 
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