TECHNOLOGY COSTING OF COLUMN

1. CONSTRUCTION TECHNOLOGY
COSTING OF COLUMN
GROUP N0 01

2. CONTENT
INTRODUCTION
SITE VISIT
CALCULATION
DISCUSSION
SUMMARY
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3. INTRODUCTION
Column.
 A column or pillar in architecture and structural engineering is a
structural element that transmits, through compression, the weight
of the structure above to other structural elements below.
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4. INTRODUCTION
Types of Columns
 Based on slenderness ratio (critical buckling length), Long
column, Short column, Intermediate column.
 Based on shape, Rectangular, Square, Circular, Polygon
 Based on type of loading, Axially loaded columns, Axial load
and un-axial bending column, Axial load and biaxial bending
column
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5. INTRODUCTION
RCC column (reinforced concrete column)
 Structural member designed to carry compressive loads with
steel frame composed with concrete.
 Columns especially slender columns may be subjected to lateral
loads and moment's.
 At times tensile stress may also develop especially in columns
at outer periphery of the building.
 Steel can take care of this tensile stress.
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6. SITE VISIT
SITE DETAIL
 Project name BMW
 Project Details
 Client Prime Homes
 Consultant Aruth Badaraji
 Contractor Nikko Construction (pvt) Ltd
 Date of commence 23/July/2016
 Date of completion April 2018
 Project Value 150 Millions
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7. SITE VISIT
 Current status of project
 Progress Structural 6th Floor
 Masonry 3rd Floor completed
 No of stories 6 story
 Type of Construction Apartment
 Location Bauddaloka
Mawatha
 Land Area 4000 sqft
 Architect Anil Kumara
 Structural Engineer Laksin Cooray
 Site Engineer Ashen Udara
 Procurement Method Traditional
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8. SITE VISIT
Selected column – C37 located in 5th floor – Grid D-E / 3
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Length of column : 3000mm
T12 T12
T16
T12
T12
T16
T12T12
T16
T12
T12
T16

9. CALCULATION
 BAR SCHEDULE AND REINFORCEMENT WEIGHT
Cost Calculation
• Number of bars
No. of 12mm bars: 8
No. of 16mm bars: 4
Total no. of bars: 12
• Number of stirrups
Length of column: 3000mm
Spacing of stirrups: 150mm
3000/150 = 20
20 +1 = 21 , two stirrups used in combination , 21 *2 = 42
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Rate of steel per 1Kg = Rs. 130.00 ( Lanva )
Labor rate for reinforcement Per 1Kg = Rs 25.00

10. CALCULATION
 Total length of a stirrups
162.5mm * 4 = 650mm
70mm * 2 = 140mm
Total length = 0.79m
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11. CALCULATION
Weight of dia 12mm bar
= 7800kg/m3 * 22/7 * (12/2mm * 10-3)3 * 3000mm
= 2.73kg
Total weight
2.73 * 8 = 21.86 kg
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12. CALCULATION
Weight of 16mm bar
= 7800kg/m3 * 22/7 * (16/2mm * 10-3)3 * 3000mm
= 4.85 kg
Total weight
4.85 kg * 4 = 19.43kg
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13. CALCULATION
Weight of stirrups
= 7800kg/m3 * 22/7 * (6mm * 10-3)3 * 790mm
=0.17 kg
Total weight
0.17kg * 40 = 7.41kg
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14. CALCULATION
 Total weight of reinforcement in a column
12mm bar = 21.86 kg
16mm bar = 19.43 kg
Stirrups = 7.41 kg
TOTAL WEIGHT = 48.1 kg
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15. CALCULATION
Labor Rate for steel reinforcement - Rs 25000/= per 1ton
- Rs 25/= per 1kg
Rate for 48.1 kg = 48.1kg * 25/=
= Rs 1202 /=
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16. CALCULATION
Bar name Number of
bar
Length Diameter of
a bar
Volume of a
bar
Total volume
bar
Mass of
bars
Rate
T16 4 10' 16 mm 603429 mm³ 2413714mm³ 19.43 Kg Rs 2525.90
T12 8 10' 12 mm 339429 mm³ 2715428mm³ 21.86 Kg Rs 2841.80
Stirrups 42 31.3" 6 mm 22487.1mm³ 944458.2mm³ 7.41 Kg Rs 963.30
Total - - - - 6073600.2mm³ 48.7 Kg Rs 6331.00
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Therefore total cost for reinforcement the column =Rs.6331+Rs.1202
=Rs.7533.00

17. CALCULATION
 FOAM WORK ARRANGEMENT
COST CALCULATION
8’X 4’ PLYWOOD COST = RS 2200.00
2’X 2’ BATTEN 1FT = RS 30.00
TREAD BAR 20FT = RS 720.00
TREAD BAR 1FT COST = 720/20 = 36.00
17
9”
15”

18. CALCULATION
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FOAM WORK ARRANGEMENT

19. CALCULATION
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48”
15” 15” 18”
Height of the column = 8 ft
Gap between two tread bars = 600mm
How many tread bars need = 2400 mm/600 mm
= 4
= 4+1
= 5 x 2
= 10
Column size = 2x0.75x8 = 12
= 2x1.75x8 = 28
= 12 + 28 = 40ft2
Plywood 1ft2 cost = 2200/32 = Rs 68.75

20. CALCULATION
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For plywood 40ft2 cost = 68.75 x 40 = Rs 2750.00
2’x 2’ battens need = 0.381mm x 10 x 3.28
Horizontal = 12.5 Ft
= 0.254 mm x 10 x 3.28
= 8.3 Ft
2’x 2’ battens need Vertical = 8 x 2438mm x 3.28
= 63.981 Ft
Cost for 2’x 2’ battens = (12.5+8.3 + 63.981) x 30 = Rs
2543.43.00

21. CALCULATION
Length of useable tread bar = 400 x 10 = 4000mm
= 4000mm/10 = 400cm
= 400/30 = 13.3ft
Cost for 13.3ft tread bar = 13.3 x 36 = rs 478.8
Labor cost for 1ft2 = rs 80.00
For 40ft2 labour cost = 80 x 40 = rs 3200.00
Final cost for column form work = 2750 + 2543.43 + 478.8 + 3200
= Rs 8972.23
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22. CALCULATION
FOAM WORK ARRANGEMENT
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23. CALCULATION
cement sand Coarse
aggregate
Grade(N/mm
2)
1 3 6 10/15
1 2 4 20
1 1 ½ 3 25
1 1 2 30
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► Concreting the column
Grade of concrete
Definition
The grade of concrete refers to the ratio by which the ingredients of concrete
e.g. cement, fine aggregate (sand) and coarse aggregate is mixed.
Few commonly used nominal mix ratios for volume batching are

24. CALCULATION
 Recommended steps for concreting
 Concrete is not a single step of mixing materials and it is a process of few
important steps.
 Material selection
 Material measuring
 Mixing
 Transporting
 Placing
 Compacting
 Finishing
 Curing
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25. CALCULATION
Hardening state
After final setting time of the concrete, hardening process is started and
continue for long period of time. Concrete gains strength due to this
hardening process.
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26. CALCULATION
 Concrete pouring method of the column
Equipment’s & tools required for concrete pouring
Hand saw, Wire cutter, Brush, Shovel
Steel Brush
Air compressor
Plumb bob
Line dory
Concrete Pump
Vibrator
Trowel
Spirit Level
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27. CALCULATION
 Concrete finishing and Curing
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28. CALCULATION
 Evaluation cost for concreting
Find the volume of column:
Length = 15" (15×25=375mm)
Width = 09" (9×25=225mm)
Height = 10' (10×300=3000mm)
Therefore total volume of column = 375mm×225mm×3000mm
= 253,125,000 mm³
= 0.253125 m³
= 0.25 m³
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29. CALCULATION
Item Number of
labours
Rate per date Total cost
Skills Non
skills
Skills Non
skills
Pouring 2 3 Rs.2000 Rs.1800 Rs.8100+Rs 8000
To poker - 1 - Rs.500 Rs.500
Other works - 1 - Rs.800 Rs.800
Rs.17400.00
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Therefore total cost for concreting the column is =Rs.3416+Rs 85.20 +Rs.17400
=Rs.20901.20

30. CALCULATION
 TOTAL COST FOR THE COLUMN
Reinforcement = Rs 7533.00
Concreting = Rs 20 901.20
Foam work = Rs 8972.23
Total = Rs 37 406.23
Profit and contingencies 25% = Rs 37 406.23 * 25 %
= Rs 9351.55
Total cost for the column = Rs 46757.78
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31. Discussion
 Link Spacing and link size of the column
 Link size should be > ¼ of largest diameter of bar or 6 mm. In
our column the largest diameter was 16mm and the link size
the 16/4 = 4 mm. Therefore it is taken as 6 mm
 Link spacing should be < 12 times of smallest diameter of the
bar. Then 12 x12 = 144 mm , but the column we chosen had
the link spacing 150 mm. 125mm can be use according to ( CL
3.12.7 )
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32. Discussion
 Concrete Protection Cover
 Weight of a 1m in steel bar.
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Diameter Weight
6mm 0.22kg
8mm 0.39kg
10mm 0.62kg
12mm 0.88kg
16mm 1.58kg
20mm 2.47kg
Standard weight is calculated
by: [DxD/162

33. Cost for concrete
 1:1:2 proportion. Grade 30
 Cement amount used
 Density = 1420 and mass for cement
 d = m / V
1 Cube = 2.83 m3
Sand and gravel cube cost can be calculate by
(1 / 2.83) x V = amount in cubes.
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Cement : Sand : Gravel
1 : 1 : 2 ( volume)
¼ : ¼ : ½ ( 1 m3)
For the compaction when mixing 50%
Then the volume increased to 1.5 m3
¼ x 1.5 : ¼ x 1.5 : ½ x1.5
0.375 : 0.375 : 0.75

34. Discussion
 Ties used in columns.
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35. Discussion
 Rate of steel
Rate of steel changes according to the manufacture. In
Sanstha the rate per ton is Rs 130000/=, In melva the rate is Rs
125000/= pre ton and in GTB 123000/=.
 Formwork in columns.
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36. Discussion
 Column with footing
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Volume selected
for cost
evaluation
Height of 10 Ft

37. Discussion
 Anchorage, laps and joints of column Bar
 Anchorage
 Laps and Joints
 When both bars at a laps exists size 20 and the cover is less than (1.5
x size of the smaller bar ,transfer link should be provided throughout
the lap length. At the lap the link bar should be not less than ( ½ x
size of the smaller bar ) and the spacing should not exceeding
200mm.
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38. Summary
 What is a Column
 What is a RCC Column
 Site Visit details
 How to identify Bar schedule
 How to calculate bar weight
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39. Summary
 How to Arranged the form work for column
 How to calculate form work cost
 What are the concreting methods
 How to pouring concrete
 Grades of concrete
 Finalize the cost of building a column
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40. Questions
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41. THANK YOU
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