Problem 3 [20 points]: A contractor is planning to use an elevating scraper for a small cut and fill operation (1,200 BCY). The material to be hauled weighs 3,000 lb/bcy with a swell estimated to be 10% and shrinkage 20%. The rated heaped capacity is 11 cubic yards, and the rated maximum load is 28,000 lb. The scraper empty weight is equal to 36,000 lb. Its weight distribution while Empty is: 66% (Drive Axle), and 34% (Rear axle). Its weight distribution at rated max load is: 52% (Drive Axle), 48% (Rear axle). The distance between the cut and fill sites is equal to 1 mile through a linear road in firm earth with rolling resistance equal to 120 lb/ton. The scraper first climbs the road at an average uphill grade of 4% when hauling material the utilizes the same road to return empty. fixed time is equal to 1.5 minutes. Performance chart for given scraper is attached. Assume that traction and elevation do not affect performance.

Table 5.1 Operating Factors for Earthmoving Operations Walker's Building Estimator's Reference Book, 25th ed. (Lisle, IL: Frank R. Walker Company, 1995), p. 2.38 . Gross Weight