$1.$ A contractor has just been awarded a contract to construct a parking lot for a small shoppingcenter. The soil conditions are very poor, and the designer has decided to bridge over the poormaterial with a structural fill, $3$ feet deep. The total estimated volume of material required is$14,000$ compacted cubic yards. The fill material is a sandy clay weighing $2,600$ pounds per bankcubic yard. The percent swell for the fill material is estimated to be $25\%,$ and the percent shrink$-$age at the design density is estimated to be $15\%.$ The contractor has selected a borrow sourcethat is $0\mathrm{.}5$ mile from the construction site. The contractor plans to maintain the haul road with agrader, and the resulting rolling resistance is estimated to be $55$ pounds per ton. The coefficient oftraction is estimated to be $0\mathrm{.}6.$ The haul road has an uphill grade of $2\%$ when traveling from theconstruction site to the dump area. Job conditions are considered to be favorable. The contractorplans to use elevating scrapers to construct the fill. Information about the scraper and performancecharacteristics are provided in Example $9\mathrm{.}2$ and Figure $9\mathrm{.}9.$ How many scrapers should the contrac$-$tor use to complete the fill in five days, if he works $50$ minutes per hour and nine hours per day?