Construction Project Report

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PreliminaryCalculationsforteam3.pdf

Preliminary Calculations Earthmoving Fleet Productivity and Project Time Estimation

Project Information

The project consists of excavating a rectangular site and hauling the material to a disposal area located 4 miles away.

Site Dimensions

Parameter Value Length 300 yd

Width 200 yd Excavation Depth 5 ft

Soil Type Common Earth Swell Factor 25%

Haul Distance 4 miles Haul Grade 4% upgrade

1. Total Excavation Quantity Bank Volume (BCY)

Excavation volume is calculated as:

V = L \times W \times D

Depth must be converted to yards:

5 ft = \frac{5}{3} = 1.667\ yd

V = 300 \times 200 \times 1.667

V = 100,020 \approx 100,000\ BCY

Loose Volume (LCY)

With a 25% swell factor:

LCY = BCY (1 + swell)

LCY = 100,000 (1.25)

LCY = 125,000\ LCY

Therefore, the trucks must haul:

125,000 LCY

2. Equipment Selection The following equipment was selected for the earthmoving operation.

Equipment Model Key Specifications Excavator CAT 336 Bucket capacity = 2.5 yd³ Dump Truck CAT 730 ADT Capacity = 20 LCY Dozer CAT D6 Used for site support and

grading

3. Excavator Productivity Excavator cycle time is assumed to be 25 seconds.

Cycles per Hour

3600 25 = 144 c𝑦𝑐𝑙𝑒𝑠/ℎr

Adjusting for job efficiency (0.83):

144 × 0.83 = 119.5 ≈ 120 c𝑦𝑐𝑙𝑒𝑠/ℎ𝑟

Excavator Production

𝑃𝑟𝑜𝑑𝑢𝑐𝑡𝑖𝑜𝑛 = 𝑐𝑦𝑐𝑙𝑒𝑠/ℎ𝑟 × 𝑏𝑢𝑐𝑘𝑒𝑡 c𝑎𝑝𝑎𝑐𝑖𝑡𝑦

𝑃𝑟𝑜𝑑𝑢𝑐𝑡𝑖𝑜𝑛 = 120 × 2.5

𝑃𝑟𝑜𝑑𝑢𝑐𝑡𝑖𝑜𝑛 = 300 𝐶𝑌/ℎ𝑟

Excavator productivity:

300 𝐿𝐶𝑌/ℎ𝑟

4. Truck Cycle Time Haul distance to disposal site = 4 miles

Assume average truck speed = 30 mph

Haul Time

4 30 = 0.133 ℎ𝑟

0.133 × 60 = 8 m𝑖𝑛𝑢𝑡𝑒𝑠

Return Time

Return travel time = 8 minutes

Additional Operation Times

Operation Time Loading 2 min Dumping 1min

Spotting / Maneuvering 1min

Total Cycle Time

CT = 2 + 8 + 1 + 8 + 1

CT = 20 minutes

5. Truck Productivity Formula

𝑄 = 𝑞 × 60 × 𝑁 × 𝐸

𝐶𝑇

Where:

Variable Description q truck capacity

N number of trucks

E job efficiency

CT cycle time

6. Fleet Productivity Calculations Fleet 1 – Primary Fleet Equipment:

• 1 CAT 336 Excavator • 4 CAT 730 Dump Trucks • 1 CAT D6 Dozer

Truck Production

𝑄 = 20 × 60 × 4 × 0.83

20

𝑄 = 199 𝐿𝐶𝑌/ℎ𝑟

Excavator capacity = 300 LCY/hr

Fleet productivity is limited by trucks.

Fleet Production = 199 LCY/hr

Project Time

𝑇 = 125000 199

T = 628\ hours

𝐷𝑎𝑦𝑠 = 628 8 = 78.5 days

Fleet 2 – Alternative Fleet 1 Equipment:

• 1 CAT 336 Excavator • 5 CAT 730 Dump Trucks • 1 CAT D6 Dozer

Truck Production

𝑄 = 20 × 60 × 5 × 0.83

20

𝑄 = 249 𝐿𝐶𝑌/ℎ𝑟

Excavator limit = 300 LCY/hr

Fleet Production = 249 LCY/hr

Project Time

𝑇 = 125000 249

T = 502 hours

𝐷𝑎𝑦𝑠 = 502 8 = 62.7 Days

Fleet 3 – Alternative Fleet 2 Equipment:

• 1 CAT 336 Excavator • 6 CAT 730 Dump Trucks • 1 CAT D6 Dozer

Truck Production

𝑄 = 20 × 60 × 6 × 0.83

20

Q = 299 LCY/hr

Excavator limit = 300 LCY/hr

Fleet Production = 299 LCY/hr

Project Time

𝑇 = 125000 299

T = 418 hours

𝐷𝑎𝑦𝑠 = 418 8 = 52.3 𝐷𝑎𝑦𝑠

7. Fleet Comparison Fleet Numbers of

Trucks Productivity (LCY/hr)

Total Hours Total Days

Primary Fleet 4 199 628 78.5 Alternative Fleet 1 5 249 502 62.7

Alternative Fleet 2 6 299 418 52.3

8. Conclusion Increasing the number of dump trucks improves hauling productivity and reduces project duration.

The Alternative Fleet 2 (6 trucks) provides the highest productivity and the shortest estimated completion time of approximately 52 days.