a 5. A contractor has a fleet of seven single engine scrapers that she plans to use to construct a 100,000 compacted cubic yard fill. Soil tests indicate that the fill material is well-graded sandy clay weighing 2,850 pounds per bank cubic yard with a swell of 35% and a shrinkage of 20% when compacted to the design density. The contractor must transport the fill over a mile-long haul road that has an average uphill slope of 3% when traveling from the borrow site. The rolling resistance of the haul road is estimated to be 90 pounds per ton, and the coefficient of traction is estimated to be 0.4. Road conditions limit the maximum speed to 28 miles per hour. Job conditions are considered unfavorable. The contractor has one tracked dozer that she plans to use to push-load the scrapers to 95% of their rated heaped capacity. Ownership and operating cost for each scraper is about $196 per hour and for the tracked dozer about $135 per hour. The scraper operator's wage is $61 per hour and the dozer operator's wage is $58 per hour. Job efficiency is estimated to be 45 minutes per hour. Information about the scraper and performance characteristics are provided in Example 9.3 and Figure 9.11. 136 Scrapers a. b. How many compacted cubic yards of fill can be excavated, hauled, and spread per hour Is productivity determined by the number of scrapers or the number of pushers? What is the unit cost per compacted cubic yard to excavate, haul, and spread the fill material c. a 5. A contractor has a fleet of seven single engine scrapers that she plans to use to construct a 100,000 compacted cubic yard fill. Soil tests indicate that the fill material is well-graded sandy clay weighing 2,850 pounds per bank cubic yard with a swell of 35% and a shrinkage of 20% when compacted to the design density. The contractor must transport the fill over a mile-long haul road that has an average uphill slope of 3% when traveling from the borrow site. The rolling resistance of the haul road is estimated to be 90 pounds per ton, and the coefficient of traction is estimated to be 0.4. Road conditions limit the maximum speed to 28 miles per hour. Job conditions are considered unfavorable. The contractor has one tracked dozer that she plans to use to push-load the scrapers to 95% of their rated heaped capacity. Ownership and operating cost for each scraper is about $196 per hour and for the tracked dozer about $135 per hour. The scraper operator's wage is $61 per hour and the dozer operator's wage is $58 per hour. Job efficiency is estimated to be 45 minutes per hour. Information about the scraper and performance characteristics are provided in Example 9.3 and Figure 9.11. 136 Scrapers a. b. How many compacted cubic yards of fill can be excavated, hauled, and spread per hour Is productivity determined by the number of scrapers or the number of pushers? What is the unit cost per compacted cubic yard to excavate, haul, and spread the fill material c
