CYL CPL 0801621 - Caterpillar

Factors to Consider
To determine the most practical location for setting the stringline, the following factors should be considered:1. Dimensional limitations of the paving machines. These include: * Lane width* Reach of the grade controls* Compatibility of the fine grader, spreader, and paver2. Terrain.3. Location of signs, utility poles, trees, and other obstacles.4. Material hauling requirements. Adequate space must be allowed for the trucks. Also, the trucks must not get close enough to the survey hubs or stringline stakes to disturb the soil.5. The distance between the stringline stakes should be decreased at curves, transitions, and super elevations.6. An adequate supply of stringline equipment makes the job go smoother. Enough stringline assures the paver is not slowed by the stringline crew.Stringline Configurations
Dual stringlines are used for high accuracy, multi-lane roads. Grade sensors sense the stringlines on both sides of the machine. The distance from the top of the survey hub to the stringline must be the same on both sides.Dual stringlines are used where there are space restrictions or multiple, non-uniform changes in slope or crown. These changes may be for special drainage or transition requirements.Single stringlines are used to control the elevation on one side of the machine. A slope sensor controls the cross slope and, therefore, the elevation of the other side.Setting Stringline
1. Assemble stringline holder (2) and rod bracket (3) to stake (1). The notched end of the holder should be about 300 mm (12 in) from the stake. The rod bracket should be about 150 mm (6 in) from the blunt end of the stake.2. Install one stake at each survey hub. Drive the stake about 300 mm (12 in) outside the survey hub. Each stake must be vertical and driven deeply enough to be stable. The notched end of the stringline holder must be directly above the tack.3. Use a plumb bob to align the notch to the tack.4. Use a rod marked with the precise length to put the notch the correct height above the survey hub. If "cut" or "fill" hubs are used, the height of the stringline must be calculated. The height of the stringline above the pavement surface must be the same.5. After the stringline stakes are positioned, install one stringline take-up reel about 7.5 m (25 ft) before the first stringline stake. Offset the take-up reel about 300 to 450 mm (12 to 18 in) outside the line of stakes, with the crank handle to the outside.6. Drive two stakes through the pockets of the take-up reel. Slide the reel up the stakes to a height that is convenient for turning the crank.7. Drive another stringline stake midway between the first stake and the take-up reel. The stringline holder of the mid-point stake should be 25 to 50 mm (1 to 2 in) higher than the other holders. This stake relieves strain on the other stakes and prevents the grade sensor from following the take-up line.8. Reel out the stringline. To reel out the stringline rapidly, place a storage