COST OF HANDLING AND COST OF HANDLING AND TRANSPORTING MATERIALTRANSPORTING MATERIAL

TA.Ahmed Mohamed EldeebTA.Ahmed Mohamed Eldeeb

Teacher assistant AUCTeacher assistant AUC

COST OF HANDLING AND TRANSPORTING MATERIAL

In many instances, Engineering materials are delivered by the seller or producer directly to the project in trucks. However, in other instances the materials must be obtained by the contractor at the storage yard of the supplier.

Some projects require the use of aggregates, sand and gravel, or crushed stone, which are produced from natural deposits or quarries and hauled to them project in trucks or tractor-pulled wagons. The handling and hauling may be done by a contractor, using his or her laborers and equipment, or it may be accomplished through a subcontractor. Regardless of the method used, it will involve a cost which must be included in the estimate for a project. When estimating the time required by a truck for a round trip, the estimator should divide the round-trip time into four elements:

1 .Loading2 .Hauling, loaded

3 .Unloading4 .Returning, empty

The time required for each element should be estimated. If elements 2 and 4 require the same time, they may be combined. Since the time required for hauling and returning will depend on the distance and the effective speed, it is necessary to determine the probable speed at which a vehicle can travel along the given haul road for the conditions that will exist. Speeds are dependent on the vehicle, traffic congestion, condition of the road, and other factors. An appropriate operating| factor should be used in determining production rates. For example, if a truck will operate only 45min/h, this time should be used in determining the number of round trips the truck will make in 1 h.

While the discussions and examples given in this part of work do not include all types of handling and transporting, they should serve as guides to illustrate methods which may be applied to any job.

Lumber is usually loaded by laborers directly onto flatbed trucks, hauled to the Job, and stacked according to size.

A laborer should be able to handle lumber at a rate of 2,000 to 4,000 Feet Board Measure per hour (fbm/h), using the lower rate for small pieces and the |higher rate for large pieces. A fair average rate should be about 3,000 fbm/h.

Trucks of the type generally used will haul 2 to 6 tons, corresponding to 1,000 'to 3,000 fbm per load. The average speed will vary with the distance, type of road, |traffic congestion, and weather.

Estimate the cost of transporting 40,000 fbm of lumber from a lumberyard to a job site. The lumber will be transported by trucks which can carry 2,000 fbm per load. The job site is 2 miles (mi) from the lumberyard- An examination of the haul road indicates an average speed of 20 mi/h for the trucks, including necessary delays to check oil, gasoline, water, etc. Assume that a worker will handle 3,000 fbm/h of lumber. Based on using two workers,( a truck driver and a laborer), and one truck, the length of the job can be determined as follows:

Rate of loading a truck, 2 x 3,000 = 6,000 fbm/hTime to load a truck, 2,000 / 6,000 = 0.33 h = 20 min.Time to unload a truck, 2,000 / 6,000 = 0.33 h = 20 min.Travel time, round trip, 4 mi / 20 mi/h = 0.20 h = 12min.Total time per load = 0.86 h = 52 min.No.(Cycles) trips per h, 1/0.86 = 60/52 = 1.16 tripsQuantity hauled per hour (Production rate) 1.16 x 2,000 = 2,320 fbm/h

Total time for the job, 40,000 / 2,320 = 17.2 h

An alternative method of determining the length of the job is as follows:

No. truckloads required, 40,000 / 2,000 = 20 truckloadsRound-trip time per load, 0.86 hTotal time for the job, 20 x 0.86 = 17.2 h

The cost will be (Assuming rate of truck is $10.58/h, of driver $8.10/h, for laborer $7.50/h)Truck, 17.2h@$10.58 =$181.98Truck driver, 17.2h@$8.10 =$139.32Laborer, 17.2h@$7.50 = 129.00

Total cost = $450.30 per total job Cost per 1000 fbm,$450.30 / 40 =$ 11.26

Based on the use of two laborers who remain at the yard, two laborers who unload the trucks at the job, and a driver for each truck, with the drivers to assist in loading and unloading the trucks, the costs can be determined as follows:

Rate of loading truck. 3 x 3,000 = 9,000 fbm/hTime to load a truck, 2,000 / 9,000 = 0.222 h = 13.32 min.Time to unload a truck, 2,000 / 9,000 = 0.222 h= 13.32

min .Travel time, round trip, 4 mi /20 rni/h = 0.200 h = 12 min.

Total time per load (Cycle time) = 0.644 h = 38.64min.No. trips per h per truck, 1 / 0.644 = 1.55 trips

Round-trip time 0.644No. trucks required, Time to load 0.222

=2.9 trucks

An alternate method of determining the number of trucks required is as follows:

No. trips per h per truck = 155Quantity of lumber hauled per h per truck, 1.55 trips x 2,000 fbm = 3,100 fbm

No. trucks required, 9,000 / 3,100 = 2.9 trucksDetermine the cost, using 3 trucks

Total time for the job, 40,000 fbm / 9,000 fbm/h = 4.44 h

The cost will be Trucks, 3 x 4.44 = 13.32h @ $10.58 = $140.93 Truck drivers, 13.32 h @ $8.10 = $107.89

Laborers, 4 x 4.44 = 17.76 h @ $7.50 =$ 133.20 Total cost = $382.02

Determine the cost, using 2 trucks. Since there are not enough trucks to keep the laborers busy, the rate of hauling will determine the length of the job.

Quantity hauled per truck, 1.55 x 2,000 = 3100 fbm/hQuantity hauled by two trucks = 6200 fbm/hTotal time required for Job, 40,000 / 6,200 = 6.45hThe cost will be:

Trucks, 2 x 6.45 = 12.9 h @ $10.58 = $136.48 Truck drivers, 12.9h@$8.10 = $104.49

Laborers, 4 x 6.45 = 25.8 h @ $7.50 =$19.50 Total cost = $434.47

Note that the total costs are based on labor and truck costs for the actual time at work, with no allowance for laborers and trucks while they are waiting their turn to start working- If there will be costs during such nonproductive times, the total cost of the job will be higher than the values calculated.

Sand and gravel are strip-mined by companies and stockpiled for use on construction projects. Sand is generally excavated from riverbeds by draglines, loaded into trucks, and transported to a central location for later distribution to prospective buyers, Similarly, gravel is strip-mined from a rock quarry, crushed in a rock-crushing machine, screened, and transported by trucks to a central gravel yard. Sand and gravel can be handled by several types of equipment, such as clamshells, front-end loaders, or portable conveyers. Small quantities may be handled by common laborers.

Portable belt conveyers are used frequently for handling and transportingmaterial such as earth, sand, gravel, crushed stone, concrete, etc. Because of the continuous flow of material at relatively high speeds, belt conveyers have high production for handling material.

The amount of material that can be handled by a conveyer depends on the width and speed of the belt and on the angle of repose for the material. Portable belt conveyers are available in lengths of 33 to 60 ft, with belt widths of 18 to 30 in, the maximum speeds of conveyer belts range from 250 to 450ft/min. A 300-ft/min belt speed is representative for many job sites. Table below gives the areas of cross section of materials with various angles of repose.

Table of cross section of materials for loaded belts, ft2

Width of belt, in Angle of repose

10° 20° 30° 18 0,134 0.174 0.214 24 0.257 0.331 0.410 30 0.421 0.541 0.668

A portable belt conveyer is used to load sand from a stockpile into trucks. The conveyer has a 24-in-wide belt which has a travel speed of 300 ft/min. The conveyer will load 12-yd3 dump trucks that will haul the sand 4 mi at an average travel speed of 30 mi/h. Assume a dump time of 2 min and an angle of repose of the sand of 20°. Determine the number of trucks required to balance the production rate of the belt conveyer.Production rate of conveyer, 300 ft/min x 0.331 ft2 = 99.3 Cu.feet/min The hourly production rate will be (99,3 cu.f./min / 27cu.f./cu.yrd) x60min/h = 220.7 cu.yrd. /h

The cycle time for a truck isTime to load, 12 yd3 / 220.7 yd3/h = 0.05 h = .05 x 60 = 3min.Time to haul, 4 mi / 30 mi/h = 0.13 h = .13 x 60 = 7.8 min.Time to dump, 2 min / 60 min/h = 0.03 h = .o3 x 60 = 1.8 minTime to return, 4 mi / 30 mi/h = 0.13 h = 13 x 60 = 7.8 minRound-trip time per truck = 0.34 h = .34 x 60 = 20.4 min.

Quantity hauled per hour, 12 yd3 / 0.34 h = 35.3 yd3/hNumber of trucks required, 220.7 yd3 /h / 35.3 yd3/h = 6.2 trucksTherefore 6 or 7 trucks are required

The following example illustrates a method of determining the cost ofunloading and hauling the material to a job.

Estimate the probable cost of loading 160yd3 of gravel from a stockpile into trucks and hauling it 3 mi to a project. Use a 0.5 yd3 truck-mounted clamshell to load 6-yd3 dump trucks. The trucks can maintain an average speed of 30 mi/h hauling and returning to the cars- The truck time at the dump will average 8 min, including the time required to check, service, and refuel a truck.

The clamshell should handle an average of 32 yd3/h allowing time for moving the clamshell and for other minor delays. The estimated cost can be determined as follows:

Time to load a truck, 6 yd3 / 32 yd3/h = 0.188 h

Travel time, round trip, 6 mi / 30 mi/h = 0.200 hTime at dump, 8 min / 60 min/h = 0.133 hTotal round-trip time = 0.521 hNo. loads per h per truck, 1.00 / 0.521 = 1.92Volume hauled per truck per h, 6 x 1.92 = 11.52 yd3No. trucks required, 32 yd3 / 11.52 = 2.78If 3 trucks are used, the time required to complete the job will be 160 yd3/

32 yd3/h = 5 h.

The cost will beMoving clamshell to and from job = $420.00 (Assumption) Cost of clamshell. 5 h @ $57.50 = 287.5Trucks, 3 x 5 = 15 h @ $16.80 = 252.00Clamshell operator, 5 h @ $17.25 = 86.25Clamshell oiler, 5 h @ $11.25 = 56.25Truck drivers, 3 x 5 = 15 h (a) $8.10 = 121.5Laborers, 2 x 5 = 10 h @ $7.50 = 75.00

Total cost = $1,298.50

If 2 trucks are used, the length of the job will be determined by the rate at which the trucks haul the gravel. As previously determined, a truck should haul 11.58 yd3/h.Two trucks should haul 2 x 11.58 = 23.16 yd3/h.The length of the job will be 160 / 23.16 = 6.9 h.

The cost will beMoving clamshell to and from job = $ 420.00Cost of clamshell, 6.9 h @ $57.50 = 396.75Trucks, 2 x 6.9 = 13.8 h @ $16.80 = 231.84Clamshell operator, 6.9 h @ $17.25 = 119.03Clamshell oiler, 6.9 h@ $11.25 = 77.63Truck drivers, 2 x 6.9 = 13.8 h @ $8.10 = 111.78Laborers, 2 x 6.9 = 13.8 h @. $7.50 = 103.50

Total cost = $1,460.53

Thus it is cheaper to use 3 trucks.If a foreman is used to supervise the job, her or his salary should be added to the cost of the project.

The costs determined in previous examples are the minimum amounts, based on the assumption that the cost durations can be limited to 5 or 6.9 h. It may be impossible or impractical to limit the costs to these respective durations. If such is the case, the appropriate durations should be used.

Bricks are generally loaded at the brick supplier by forklifts or small cranes that are fitted on the bed of flatbed trucks and hauled to a project. The capacity of the trucks is normally 2,000 to 3,000 bricks per load. Popular sizes of building bricks weigh about 4 lb each.

Upon arrival at the project, the bricks are unloaded by a small crane that is mounted on the truck, or by a forklift, onto small four-wheel tractors that transport bricks around the perimeter of the structure where the bricks are to be laid.

Workers, using brick tongs, can carry 6 to 10 bricks per load to the brickmason for laying. A worker should be able to pick up a load, walk to the location of the brick mason and deposit the load, and return for another load in 0.5 to 1 min per trip. If it is assumed that the average time for a trip is 3/4 min and the work carries 8 bricks per trip, in 1 h he or she will handle 640 bricks. The actual number of bricks, worker can handle will depend on the job site conditions at a particular. The following table provides rates for various job conditions.

Bricks Trip Bricks Hourscarried time, handled per 1,000per trip min per hour bricks

6 0.5 720 1.398 0.5 960 1.0410 0.5 1,200 0.836 0.75 480 2.088 0.75 640 1.5610 0.75 800 1.256 1.00 360 2.788 1.00 480 2.08

10 1.00 600 1.6

The cost for 60,000 bricks from a supplier includes delivering, unloading, and stacking the bricks at a central location at the job site. Estimate the cost of transporting the bricks from the central location where they are stacked by the supplier to the structure where they will be installed by a brick mason. The bricks will be hauled by a small four-wheel tractor at a rate of 1800 bricks per hour.Laborers will be stationed around the perimeter of the structure to carrybricks to the brick masons. Assume each laborer will carry 8 bricks per load and average 3/4 min per trip each way.No. bricks handled per labor-hour will be 8 x 60 /0.75 = 640Time to haul bricks by tractor = 60,000 / 1,800 per h = 33.33 hTime to haul bricks by laborers = 60,000 / 640 per h = 93.75 h

The costs will beTractor, 33.33 h @ $19.00 = $ 633.27Operator, 33.33 h @ $9.50 = 316.64Laborers, 93.75 h @ $7.50 = 703.13Total cost =$1,653.04

The cost for handling bricks is $1,653.04 / 60,000 = $0.028 per brick .

Estimate the cost of hauling 60,000 bricks from the brickyard supplier to a job 4 mi distant. Each truck will haul 3,000 bricks per load and can travel at an average speed of 20 mi/h loaded and at 30 mi/h empty, allowing for lost time. Three laborers will be stationed at the yard to load the trucks, and another three be at the job to unload the trucks. The truck drivers will assist in loading unloading the trucks. Each laborer will carry 8 bricks at the yard and at the job. Assume that a laborer will average 3/4 min per trip at the yard and at the job.No. bricks handled per labor-hour. 8 x 60 ÷ 0.75 = 640Rate of loading a truck, 4 x 640 = 2,560 per hTime to load a truck, 3,000 ÷ 2,560 = 1.170 hTime to unload a truck, same = 1.170 hTime to drive from yard to job, 4 ÷ 20 = 0.200

Time to drive from job to yard, 4 ÷ 30 = 0.133 hTotal Time for round trip = 2.673 hNo. bricks hauled per h per truck, 3,000 ÷ 2.673 = 1,122No. trucks required to haul 2,560 bricks per h, 2,560 ÷ 1,122 = 2.28 trucks

It will be necessary to use either 2 or 3 trucks. If 2 trucks are used, the cost will be determined as follows.Rate of hauling bricks, 2 x 1,122 = 2,244 per hTime required to finish the Job, 60,000 ÷ 2.244 = 26.7 hThe cost will beTrucks, 2 x 26.7 = 53.4 h @ $22.80 = $1,217.52Truck drivers, 53.4 h @, $8.10 = 432.54Laborers, 6 x 26.7 = 160.2 h @ $7.50 = 1,201.

Total cost = $2,851.56

If 3 trucks are used, the rate of loading the trucks, as previously determined, will be 2,560 bricks per hour.Time required to finish the job, 60,000 ÷ 2,560 = 23.5 hThe cost will beTrucks, 3 x 23.5 = 70.5 h @ $22.80 = $1,607.40Truck drivers, 70.5 h @ $8.10 = 571.05Laborers, 6 x 23.5 = 141.0 h @ $7.50 = 1,057.50

Total cost = $3,235.95

It will be more economical to use 2 trucks.

This project involves loading cast-iron pipe onto trucks and hauling it to a project, where it will be laid on the ground along city streets. The average haul distance will be 5 mi.

The pipe will be 12 in. in diameter and 18 ft long and weigh 1,140 Ib per joint of 18 ft . A 4-ton truck-mounted crane will be used to load the pipe onto 8-ton trucks, which will haul 14 joints per load. The pipe will be unloaded from the trucks by an 80-hp crawler tractor, with a side boom, which will move along with the trucks.

The trucks can average 25 mi/h loaded and 30 mi/h empty.The total labor crew will consist of the following persons:

At the loading site 1 crane operator

1 crane oiler 2 laborers with the crane

2 laborers on the truckAt the unloading site

1 tractor operator 2 laborers helping unload pipe

Determine the number of trucks required and the direct cost per foot fortransporting the pipe.

The time required by a truck for a round trip will be:Assuming the time required to load or unload of one joint is 3 min.Loading truck, 14 joints x 3 min/joint = 42 min ÷ 60 = 0.70 hHauling to job, 5 mi / 25 mi/h = 0.20 hUnloading truck, 14 joints x 3 min/joint = 42 min ÷ 60 = 0.70 hReturning to car, 5 mi / 30 mi/h = 0.17 hTotal time = 1.77 hNo. trips per h, 1 ÷ 1.77 = 0.565

No. joints hauled per h per truck, 0.565 x 14 = 7.9 jointsNo. joints unloaded per h, 60 ÷ 3 = 20 jointsNo. trucks required, 20 ÷ 7.9 = 2.54 trucksUse 3 trucks

Assume that the crane and truck will operate 50 min/h. The average numbof joints hauled per hour will be 20 x 50 ÷ 60 = 16.67 joists

The cost per h will be:

Crane, 1 h @ $62.75 = $ 62.75Trucks, 3 h @ $22.50 = 67.50Tractor with boom, 1 h @ $18.20 = 18.20Crane operator, 1 h @ $17.25 = 17.25Crane oiler, lh @ $l 1.25 = 11.25Tractor operator, 1 h @ $15.86 = 15.86Truck drivers, 3 h @ $8.10 = 24.30Laborers, 6 h @ $7.50 = 45.00Foreman, 1 h @ $17.30 = 17.30Total cost = $279.41Cost per ft, $279.41 ÷ (18 x 16.67) = 0.931

Any cost of moving equipment to the job and back to the storage yard should be prorated to the total length of pipe handled, and added to the unit cost determined above, to obtain the total cost per unit length.

1-Estimate the total direct cost and the cost per 1,000 fbm of lumber for transport 50,000 fbm of lumber from a lumberyard to a job which is 3 mi from the yard. A 5- stake-body truck will haul 3,000 fbm per load. The trucks can average 25 mi/h loaded and 40 mi/h empty.

One laborer plus the truck driver will load lumber onto the truck at the lumberyard, and another laborer plus the truck driver will unload the truck and stack lumber at the job. Each worker will handle 1,200 fbm/h when working.

Assume that the laborers and the trucks operate 50 min/h. Determine the most economical number of trucks to use.

Will placing an additional laborer at the yard and at the job reduce the cost of handling and hauling the lumber?

Labor and truck costs per hour will be

Trucks $16.40Truck drivers 9.25Laborers 7.30

2- Using the information given in Prob. 1, is it less expensive to keep two laborers at the yard and two other laborers at the job site or to use only two laborers, who will ride with the truck driver to load and unload a truck?

3-The owner of a sand and gravel pit is considering the purchase of a fleet of trucks to deliver aggregate to customers. Two sizes are being considered, namely, 10- and 15-yd³ diesel-engine-powered dump trucks. The haul distances will vary from 6 to 20 mi, with an average distance of about 12 mi.

It is estimated that the 10-yd³ trucks can travel at an average speed of40mi/h loaded and at 50 mi/h empty, while the 15-yd³ trucks can travel at an average speed of 35 mi/h loaded and at 45 mi/h empty.

The trucks will be loaded from stockpiles of aggregate, using a 2-yd³ clamshell with an angle of swing averaging 90°. See THE Table TO GET the output for the clamshell. The average truck time at the dump will be 4 min for the 10-yd3 truck and 5 min for the 15-yd3 truck. Assume that the trucks and the clamshell will operate 45 min/h.

Determine which size truck is more economical.

The cost of a 10-yd³ truck is $27,10 per hour, and that of a 15-yd³ truck is $43.55 per hour. A truck driver will be paid $9.50 per hour. Because the cost of the clamshell will be the same for each size truck, this cost need not be considered.

4-Is it more economical to use a 1- or a 2-yd³ clamshell to load sand and gravel from stockpiles into 10-yd3 diesel-engine-powered dump trucks? Assume an average angle of swing of 90° from the clamshell.

Use THE Table to determine the production rate for each clamshell. In addition lo the time required by a clamshell to load a truck, there will be an average delay of 2 min waiting for another truck to move into position for loading. Assume a 50-min hour for both the

clamshell and the trucks. The costs per hour will be-:

1-yd³ clamshell $38.852-yd³ clamshell 72.15

Truck 29.50Truck driver 9.50Clamshell operator 18.20Clamshell oiler 12.40

5-A total of 140,000 bricks is to be hauled from a brickyard by 5-ton gasoline-engine- powered stake-body trucks to a project 4 mi from the yard. A truck, which can haul 3,000 bricks per load, will average 30 mi/h loaded and 40 mi/h empty. Assume that the trucks operate 45 min/h.

Determine the total cost and the cost per 1,000 bricks for each of the stated conditions.

(a) Three laborers plus a truck driver will each load 450 bricks per hour onto a truck, and three other laborers plus a truck driver will unload the bricks from a truck at the job at the same rate.

(b) Three laborers plus a truck driver will each load 450 bricks per hour onto a truck; then the truck driver and the three laborers will ride on the truck to the job, where they and the truck driver will unload the bricks at the same rate as at the yard. The costs per hour will be

Truck, each $15.75Truck driver 9.50Laborers, each 7.25

6-The operator of a gravel pit is invited to bid on furnishing 2,500 yd3 of bank-run gravel for a job. The gravel is to be delivered to a job, which is 12 mi from the pit. The gravel will be loaded into trucks by a hydraulic excavator which will load at a rate of 80 yd³/h. The trucks will haul 10 yd3 per load and average 35 mi/h loaded and 45 mi/h empty. Assume that the hydraulic excavator and the trucks will operate 45 min/h. The following costs will apply:

Royalty paid for gravel, $0.42 per yd³General overhead, $0.30 per yd³Profit, $0.55 per yd³Hydraulic excavator, $63.00 per hTrucks, each, $26.00 per hExcavator operator, $18.10 per hExcavator oiler, $12.50 per hTruck drivers, $9.10 per hForeman, $18.50 per hLabor taxes, 15 % of wages paid, including foremanWhat price per cubic yard should be bid?