Identify the elements of a tower crane and pricing the tower crane for a construction project

TOWER CRANE

ü A concrete pad is constructed using grade 50 concrete and with steel bars greater than T16.

ü The base is bolted to the ground.

ü Size of the concrete pad depends on the maximum height of the tower crane and the maximum load it may carry.

ü The long horizontal arm is called as working arm, which is the portion of the crane that carries the load. A trolley runs along that arm to move the load in and out from the crane's center.

ü The shorter horizontal arm is called as machinery arm, which contains the crane's motors and electronics as well as the large concrete counter weights.

ü Tower crane units are delivered to site using a long trailer.

ü Initially, tower units, boom and other equipments are assembled using a mobile crane.

ü Later when building goes up, tower crane also move up itself using hydraulic jacking system.

Jacking system

Hydraulic lifting unit lifts the rotation unit 2m above together with the arm. (arm is fixed to rotation unit). Then there will be a 2m gap between top of the last tower unit and the rotation unit. Then the tower crane itself lifts one tower unit at once and assemble it using nuts and bolt between the created gap. Later rotation unit again fixed to the top of the new tower unit.

ü This method is revised to remove the tower units after completion

ü To remove the large concrete pad (if necessary), first drill few holes in it and then add a special chemical to crack it easily.

PRICING OF TOWER CRANE FOR A 10 STOREY BUILDING

Preparation of the concerete base

Assumption

the size of the concrete base is 4 x 4 x 2.5 m3 sized made of grade 50 concrete.

the thickness of the lean concrete layer is 75 mm with grade 15 concrete.

excavated materials keep by the pit.

excavation of pit to install the concrete base.

Excavator

6

hr

@

2000.00

12000

uk labour

9

hr

@

80.00

720

12720.00

Materials for the concrete base

Total area of f/w to be provided

= (4x 4) x 2 x 2.5

= 40 m2

Volume of lean concrete

= 4 x 4 x 0.075

= 1.2 m3

Volume of grade 50 concrete

= 4 x 4 x 2.5

= 40 m3

Assumption

150 kg of 16 mm high yield steel bars are included in 1m3 of concrete

Total weight of 16mm dia r/f

= 150 x 40

= 6000 kg

= 6 T

Cost of materials

F/w

40

m2

@

800.00

32000

Lean concrete

1.2

m3

@

12500.00

15000

Grade 50 concrete

40

m3

@

14500.00

580000

R/f

6

T

@

125000.00

750000

1377000.00

Cost for curing and other related item of construction of base slab

10000.00

Tower Crane

the height of the floor of the building

3.5m

Total height of the building

35m

the maximum height of the tower crane

45m

Tower crane hiring

Assumption

Tower crane is hired from a company for monthly payment basis

monthly cost for the tower crane is Rs 200000

Expected hiring duration

12 month

Hiring cost of the tower crane

12 months

@

200000.00

2400000.00

Tower Crane transportation cost

Assumption

It need 8 trips of law bed truck to bring complete tower crane to the site

Single complete trip of the truck takes 9 hours

JCB takes 16 hrs to loading and 16 hrs to unloading

time taken to transport the complete tower crane

72

hours

Cost to transport back to the supplier after 1 yr is same as the cost of transport to

the site plus the relevant price escalation

transport cost

72

hrs

@

1200.00

86400

loading & unloading

32

hrs

@

2000.00

64000

uk labour

70

hrs

@

80.00

5600

cost of transport

156000.00

cost for transport

156000

Additional cost due to escalation

7800

cost of transport back

163800.00

Tower crane erection

Assumption

Cost of dismantling is same as the cost of erection plus the additional cost for

price escalation

It is required to hire a mobile crane for 20 hours for the rate of 3500 per hour

mobile crane

35

hrs

@

3500.00

122500

sk labour

80

hrs

@

120.00

9600

uk labour

50

hrs

@

80.00

4000

tools

1360

cost of erection

137460.00

Cost of dismantling

cost of erection

137460

Additional cost due to escalation

6873

cost of dismantling

144333.00

Demolition of concrete base

drilling the base

7000

chemical to weaken the concrete

20

lit

@

750.00

15000

breaking the concrete

30000

disposal of materials

45000

97000.00

Total cost to hire, transport and erection & dismantling of the crane

4,498,313.00

Operational Cost

Assumptions

the expected operational duration of the tower crane is 1000 hours

Consider for the complete duration

Operator

11.5

mth

@

45000.00

517500

Helper

11.5

mth

@

25000.00

287500

Generator

1000

hrs

@

200.00

200000

Diesel

15000

lit

@

75.00

1125000

Total operational cost

2,130,000.00

Total cost related to the tower crane

6,628,313.00

Number of operating hours

1000 hrs

Hourly cost of tower crane

Rs

6628.31