Question

A contractor has just been awarded a contract to construct a parking lot for a small shopping center. The soil conditions are very poor, and the designer has decided to bridge over the poor material with a structural fill 3 feet deep. The total estimated volume of material required is 14000 compacted cubic yards. The fill material is a sandy clay weighing 2600 pounds per bank cubic yard. The swell for the fill material is estimated to be 25%, and the shrinkage at the design density is estimated to be 15%. The contractor has selected a borrow source that is a half mile from the construction site. the contractor plans to maintain the haul road with a grader, and the resulting rolling resistance is estimated to be 55 pounds per ton. The coefficient of traction is estimated to be 0.6. The haul toad has an uphill grade of 2% when traveling from the construction site to the borrow site. Job conditions are considered to be favorable. The contractor plans to use Caterpillar 615C series II elevating scrapers to construct the fill. Performance characteristics of the 615C series II scraper are provided in Example 10.2 and figure 10.8. How many scrapers should the contractor use to complete the fill in 5 days, if he works 50 minutes per hour and 9 hours a day?

Answer 1