A C-27 contractor is preparing a bid for a large commercial landscape project that requires extensive earthwork, including grading and excavation. The project specifications indicate a total of 1,500 cubic yards of soil to be excavated and hauled off-site. The contractor's primary excavator can move 75 cubic yards per hour, and the hauling trucks can each carry 15 cubic yards per load. Each round trip for hauling takes 45 minutes. The hourly labor cost for the excavator operator is $65, and for each truck driver is $55. How many total hours will be required for hauling, assuming one excavator and two trucks are used, and what is the total hauling labor cost? (Assume excavator loading time is negligible compared to truck cycle time, and trucks operate efficiently.)
- AHauling Hours: 25 hours; Total Hauling Labor Cost: $2,750
- BHauling Hours: 37.5 hours; Total Hauling Labor Cost: $4,125
- CHauling Hours: 45 hours; Total Hauling Labor Cost: $4,950
- DHauling Hours: 75 hours; Total Hauling Labor Cost: $8,250
Show answer & explanationAnswer & explanation
Correct answer: B. Hauling Hours: 37.5 hours; Total Hauling Labor Cost: $4,125
Total cubic yards to haul = 1,500 CY. Each truck carries 15 CY. Number of loads per truck = 1,500 CY / 15 CY/load = 100 loads per truck. Since two trucks are used, each truck makes 100 loads. Time per load (round trip) = 45 minutes = 0.75 hours. Total hauling time for one truck = 100 loads * 0.75 hours/load = 75 hours. Since two trucks are working simultaneously on the same total volume, the total duration for hauling is determined by the time it takes for one truck to complete its share of the loads. If two trucks split the 1500 CY, each truck hauls 750 CY. Loads per truck = 750 CY / 15 CY/load = 50 loads. Total hauling time = 50 loads * 0.75 hours/load = 37.5 hours. Total hauling labor cost = 2 trucks * 37.5 hours/truck * $55/hour = $4,125.
Why the other options are wrong
- A. Incorrect calculation of total hauling hours and associated cost.
- C. Incorrect calculation of total hauling hours and associated cost.
- D. Incorrect calculation of total hauling hours, possibly assuming one truck for the entire volume.
Earthwork Hauling Cost Calculation
The process of estimating the labor and equipment costs associated with transporting excavated soil or materials off-site, considering volume, truck capacity, cycle time, and labor rates.
- Requires calculating total loads based on volume and truck capacity.
- Cycle time per load includes loading, travel, dumping, and return.
- Total hours are multiplied by labor and equipment rates for cost.
Memory trick: Load, cycle, hours, then cost, for hauling, don't get lost.