Reinforcement work

• Factors to be considered: materials,

wastage and storage.

• Various sizes.

• Need to store properly – rusty

• Labour constant – unload (carry),cut and

bend and assemble into the formwork

example1

• Calculate the cost of steel reinforcement bar Y

12 in a concrete beam.

Solutions:

Materials:

Cost of 1 tonne steel reinforcement = RM2,100

Weight of 1 m length Y12 = 0.994 kg

Labour:

Labour cost for steel fixer RM40/day

No. of labour 1 labourer

To calculate cost of materials

Cost of 1 kg steel RM2.10/kg

Add 5% wastage RM 0.11

Cost of tie (0.5kg/100 kg steel @RM2.50/kg) RM 0.02

RM 2.23

To calculate labour constant

Cost of steel fixer (assume 1 labourer)

Labour constant for unloading, cut and bend =0.25 hrs/kg

Labour constant for fixing =0.1hr/kg

Wages per day RM 40/day =RM5.00/hr

Time to unload, cut and bend (1 kg) 0.25 hr

Then cost to carry, cut and bend =RM5.00 x 0.25 hr

= RM 1.25

Time for fixing (1 kg) = 0.1 hr

cost for fixing ( 1 kg) = RM5.00 x 0.1 hr

= RM 0.50

Rate for 1 kg of steel

RM2.23 +RM 1.25 + RM0.50

=RM 3.98

+ 10% profit = RM4.38

Exercise 2

Calculate the cost 1 kg of Y12

Cost steel per tonne = RM2300

Weight Y12 for 1 m = 0.995kg

Wages per day RM45.00

Profit 20%

If the steel 40m long= ????

Exercise 3 Calculate the cost of 1 kg R6 links in a concrete

column.Numbers of links are 9 and the length for

each is 0.89m.

Cost 1 tonne of R6 RM1600

Labour cost RM40/day

Lab. Cons to unload, cut and bend 0.25 hrs/kg

Lab. Cons to fix 0.1hr/kg

Wastage 5%

Profit 10%

Weight 1 m R6 0.222kg

To calculate the cost of materials

Weight of links = 0.222kg x 0.89m x 9

=1.79 kg

Cost of 1 kg R6 = 1.79 x RM 1.60 =RM2.85

Add wastage 5% =RM0.14

=RM2.99

To calculate labour cost

Lab. Cons to unload, cut and bend 0.25hr/kg

Wages per hr RM5.00

Total cost RM 5 x 0.25 hr/kg x 1.79 kg RM2.24

Labour constant to fix = 0.1 hr/kg

Cost for fixing = 0.1 x RM5 x 1.79

= RM 0.90

Cost of material + labour

RM2.99 + RM2.24 + RM0.90

=RM6.13

Cost + 10% profit = RM6.75

Exercise 4 Calculate the cost of 1 kg reinforcement Y10

Details:

Wt of 1 ton of reinf bar = 1016kg

Cost of 1 ton Y10 =RM1200

Wastage 2 ½ %

Tie wire 0.5kg every 100kg of reinf. Bar

cost of tie wire RM2.50/kg

steel fixer to unload, cut and bend and fix 100kg of

reinforment bar requires 12 hours

Steel fixer’s wage per day RM 35

Profit 20%

To calculate the cost of materials

1 ton of reinf (1016kg) RM1200

100 kg = 1200/1016 x 100 RM118.11

wastage 2 ½ % RM2.95

Tie wire 0.5kg for every 100kg reinf@RM2.50/kg

100 kg reinf use 0.5kg x RM2.50 RM1.25

Total RM122.31

To calculate the cost of labour

1 steel fixer need 12 hrs to unload, cut , bend and fix

Cost of labourer = RM35/8 x 12 hrs = RM52.50

Total cost: materials + labour

=RM 122.31 + RM52.50

= RM 174.81

+ 20% profit = 34.96

rate for 100 kg =RM209.77

1 kg =RM2.10

formwork

• To support the concrete

• Selection of formwork depend on

quality,safety and economy.

• Must strong enough to support the wet

concrete.

• Can reuse for several times

• Labour constant for making, fixing and

stripping (eg: 1.5hr/m2)

Cost of materials

• Plywood

• Strut (to support the formwork)

• Nails and shutter oil to formwork

labour Constant

- fixing and stripping

- multiply by wage per hour

Example 1

To calculate the cost of 1 m2 of formwork:

Details:

-25mm thick plywood (2.44 m x 1.22m)@ RM 40/pc

-Can be reuse for 5 times

-Cost of nails and oil to formwork RM2.00/time

-1m2 formwork need 0.07m3 strut @260/m3

-1 labourer to fix and stripping 1m2 for 2 hrs

- wage per day RM40

-wastage 10%

- profit 10 %

To calculate the cost of materials

1 m2 of plywood RM40/(2.44 x 1.22) =RM 13.44

0.07m2 struts RM260 x 0.07 =RM 18.20

use 5 times RM 31.64

1 time RM 6.33

Wastage 10% RM6.33 x 10 % RM 0.63

Cost of nails and shutter oil RM 2.00

total cost RM 8.96

To calculate labour cost

Labour wage RM40/8 RM5/hr

Time to fix and strip 1 m2 formwork 2 hrs

Workman cost RM5/hr x 2 hrs RM10

Toatal cost : material + labour

= RM 8.96 + RM 10.00

= RM18.96

Profit (10%) RM 1.90

cost for 1 m2 = RM 20.86

Exercise 1 Calculate cost of 1 m2 of formwork:

-Plywood (2.44m x 1.22 m) @ RM35.00 /pc

-1m2 formwork need 0.06m3 strut @250/m3

- Reuse for 5 times

- Cost of nail and oil RM1.00/time

- 1 carpenter needs 1 ½ hrs to fix and strip 1 m2 of

formwork

- Carpenter’s wage RM35/day

- Working hrs 8 hrs/day

- Wastage 10%

- Profit 20%

solutions

Materials

plywood

1 m2 = RM35/(2.44 x 1.22) RM11.78

Strut 0.06 x RM 250.00 RM15.00

Cost for 5 times RM26.78

for 1 time RM 5.36

wastage 10% RM 0.54

cost of nail + oil RM1.00

cost of materials RM 6.90

Labour

1 ½ hrs to fix and strip 1 m2 form

wage per day RM35.00

Payment to carpenter 1 ½ x (35/8) =RM6.56

Material + labour = RM6.90 + RM6.56

=RM13.46

+ 20% profit = RM2.69

cost for 1 m2 formwork = RM16.15