1. BET403 Cost Engineering Individual Assignment & Group Report
2016
Lecture 4

2. Individual Assignment and Group Report
BET403 Cost Engineering
Individual Assignment and Group Report
Prepare a tender submission for the following tender:
Construction of a 24 km long 1200mm diameter concrete pipeline comprising 16 km from pumping station A to reservoir B and 8 km from B to an industrial consumer C. There is a continuous outcrop of rock from chainage 10 to 13 km
TENDER closes at 1:00 pm (13:00) on Thursday 28 April 2016
Rock tip, 5km away
Pumping station A
Industrial consumer C
Reservoir B A
rock outcrop B C 10 13 16 24
2016
Lecture 4

3. Assumptions: 1200DN Class 6 concrete pipes H2 support class
BET403 Cost Engineering
Assumptions:
1200DN Class 6 concrete pipes
H2 support class
Average backfill height 2.5m
Minimum trench width and clayey sand
Rock excavation between chainage 10 and 13 consists of 15% hard rock and 85% medium to soft rock
Provide for removal and dumping of excavated rock to tip 5 km away
2016
Lecture 4

4. Individual Assignment and Group Report
BET403 Cost Engineering
Individual Assignment and Group Report
Task
Time required (including Work Break-down Structure and Time/Location diagram)
Group
Material quantities and costing
Individual 1
Labour requirements and costing
Individual 2
Plant and equipment requirements and costing
Individual 3
Development of project price
Tender submission
2016
Lecture 4

5. BET403 Cost Engineering Group Report Individual Assignment 1:
1. Time required (including Work Break-down Structure and time/location diagram)
2. Materials quantities and costing*
3. Labour requirements and costing*
4. Plant and equipment requirements and costing*
5. Development of project price
6. Tender submission
Individual Assignment 1:
Materials quantities and costing
Individual Assignment 2:
Labour requirements and costing
Individual Assignment 3:
Plant and equipment requirements and costing
* Individual Assignments
2016
Lecture 4

6. Remove and dump excavated rock Skills required Pipelaying team
BET403 Cost Engineering
Work required
Excavate trench
Lay pipe
Testing
Remove and dump excavated rock
Skills required
Pipelaying team
1 x foreman
3 x machine operators
5 x trades people
4 x labourers
Testing team
2016
Lecture 4

7. BET403 Cost Engineering
Notes
2016

8. Quantities Source: Humes Concrete pipe reference manual
BET403 Cost Engineering
Quantities
Source: Humes Concrete pipe reference manual
2016

9. Given: Quantities BET403 Cost Engineering
1200DN Class 6 concrete pipes
H2 support class
Average backfill height 2.5m
Minimum trench width and clayey sand
Quantities
Quantities ‘out’ - Excavation quantities
Hard rock
Medium to soft rock
Clayey sand
Quantities ‘back in’
Bedding quantities
Haunch quantities
Compacted ordinary fill quantities
Backfill quantities
Pipe
Source: Humes Concrete pipe reference manual
2016

10. BET403 Cost Engineering Source: Humes Concrete pipe reference manual
2016

11. Effect of excavation and compaction
BET403 Cost Engineering
Effect of excavation and compaction
Excavation: increased volume – bulking or swelling
Compaction: decreased volume - shrinking
One cubic excavated does not translate to one cubic loose or one cubic compacted
0.95 m3
compacted
1 m3
bank/ in-situ
1.25 m3
loose/ excavated
Shrinking
Bulking
2016

12. Bulking and shrinking Bank material: Loose material:
BET403 Cost Engineering
Bulking and shrinking
Bank material:
Soil that is in its natural, or in situ, state before disturbance
Measured as bank cubic meters
Loose material:
Soil that has been disturbed and is no longer in its original state
Measured as loose cubic meters
Compacted material:
Soil that has been compacted for use in construction projects
Measured as compacted cubic meters
Source:
2016

13. Bulking (Swell) Factor (%)
BET403 Cost Engineering
Shrink factor SF = (volume of in-situ material – volume of compacted material)
volume of in-situ material
Bulk factor BF = (volume of loose material – volume of in-situ material)
Example: Bulking of excavated materials
After excavation of 300 m3 clay the volume of loose clay material swells to 420 m3 in the dump
Bulking factor = (420 – 300)/ 300
= 0.4
= 40%
Material
In-situ Density
103 (kg/m3)
Bulking (Swell) Factor (%)
Clay
1,800 – 2,600
Granite
2,600 – 2,800
Sand, dry
1,600
Sand, wet
1,950
Sandstone
2,100 – 2,400
Soil
1,200 – 1,600
Source:
2016

14. LE > LP Excavated volume = LE x d x w BET403 Cost Engineering LP
Plan A w A
LE > LP d LE
Elevation B B B A A
Excavated volume = LE x d x w B
2016