Unit 2 | unit 2 taking out quantities detailed estimate up to plinth

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QSCT

Unit 2

Method of Estimating

2.1 Method of taking out Quantities: -

The method of taking out quantities are classified as: -

1) PWD method.

2) Centre line method.

These methods explained as follows,

1) PWD method: -

It is also called as long wall / short wall method.
It consists of following steps: -

1) Taking out dimensions from respective drawing.

2) Squaring the dimension.

3) Abstracting.

The term take show measuring the dimension like L x B xH of various item of construction from related drawing and these dimensions are recorded in measurement sheet form.
The meaning of squaring the dimension indicator the multiple of dimension to find quantities it item measure in cubic metre or multiple of length and height of item is measured in sq. m and these are recorded in measure sheet form.

All quantities of various item work are calculate and filled in measurements sheet.
This method is adopted by state PWD.
The rate of item of work are either worked out or taken from DSR.
Procedure: -

 Prepare foundation plan showing centre lined with all dimension. Centre to centre dimension are taken out by adding half width of each across to inner dimension of room.

 Now divide the wall into two groups. In plane wall is horizontal direction are called ling wall and vertical wall called as short wall.

 It advised not change the group of wall to avoid error.

 Measure length of long wall for item by using formula.

Long wall length for item = length of centre line long wall + width of item.

 Measure length of short wall for item by using formula.

Short wall length for item = length of centre line of short wall – width of item.

Advantage:

1) This method is simple abs accurate.

2) There are no chance of mistakes in calculate.

3) The method gives quantity quickly.

2) Centre line method: -

As the name itself implied, the total centre line length of wall of same have similar foundation is worked from plan of structure and is then multiple by respective dimension to obtain required quantity of structures.
Total length of centre line remains same for sub structure and superstructure item except in cases where are cross wall like at junction of wall.
This method is simple and easy in calculate for same structure having no cross wall.

If there are crossed wall, then special care is to taken in taking out dimension at all such junction point.
The simple rule is to deduct half width of respective item for each junction point from total length of centre line.
In case of building have different types of wall each set wall is considered separate i. e 1st determine total length of centre line of each type and make deduction for each junction as state above and multiple by respective width and depth that item to find out its quantity.

This method have length will remain same for excavation in foundation, for concrete in foundation for all footings and for superstructure.
This method is quick and easy but required special attention and considered at junction meetings point of partition or cross wall, etc.
Procedure: -

 Prepare the foundation plan of given drawing, write centre line length of each wall.

 Find the total length of centre line of long and short wall, having same type of footing.

 Calculate the number of junction of cross wall with main or external wall. It should be noted that corner of building where two wall meet are not taken in junction and if two wall meet a wall at some point take n= 2 at that point.

 Length for item = total centre line length -n x ( ½ x width of item).

 n = number of junction of cross wall with main walls.

For building have different type of wall each set of wall is separate taken.

Advantage: -

1) It can used for calculate of quantity of rectangle circular and polygons building.

2) This method is simple and quick.

3) Calculate are easy and less.

2.2 Factor considered while preparing detailed estimate: -

1) Quantity of materials: -

For large scale construction a large quantities of materials is required and this can purchase at rate cheaper that the rate of materials is rate of materials required fir minor work. So the rate of work is frames by considering volume of work.

2) Availability of materials: -

Estimate cost of particular item is higher than schedule rate if there is no assurance that the materials will available as and when required and it determined to progress of work if worker and maintenance staff remains for paucity of materials.

3) Transportation of materials: -

If fewer quantity of materials are required transportation to consider distance, the relatives cost of transportation becomes higher in comparison with cost of large quantities transport at time

4) Location of site: -

The site of work is selected, such that reduces damage or transit during loading, unloading, stocking of materials.

5) Local labour charge: -.

The skill, suitability and wages of local labour are considered in that time while preparing the detailed estimate.

Problem:

1) Work out the following plans quantity upto plinth level of both long wall short wall method and centre line method.

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Ans : by long wall short wall method,

Long wall :

(ABC ,DEF) = 6.96m

(GH) = 4.23 m

Short wall :

(AD,BE,CF) = 4.23 m

(DG ,HI) = 3.73 m

Sr.no	Description	No	Length	Width	Height	Quantity	Total quantity
1	Earthwork in excavtion
	Long wall
	(ABC,DEF)
	L=6.96 +1 = 7.96 m	2	7.96	1	1.2	19.10m3	43.56 m3
	(GH)
	L = 4.23 + 1 = 5.23m	1	5.23	1	1.2	6.28 m3

	Short wall
	(AD,BE,CF)
	L = 4.23 - 1 = 3.23 m	3	3.23	1	1.2	11.63m3
	(DG , HI)
	L = 3.73 - 1 = 2.73 m	1	2.73	1	1.2	6.55m3

2	P.C.C
	Long wall
	(ABC .DEF)
	L = 7.96 m	2	7.96	1	0.15	2.39 m3
	(GH)
	L = 5.23	1	5.23	1	0.15	0.78m3

	Short wall
	(AD,BE,CF)
	L = 3.23 m	3	3.23	1	0.15	1.45m3
	(DG , HI)
	L = 2.73 m	1	2.73	1	0.15	0.82m3

3	Plinth quantity
	Offset = (0.43 - 0.23)/2=0.1
	Plinth dimension = clear dimension - 2 x offset
	1 . Rubble
	For kitchen						10.71 m3
	L = 3 - 0.2 = 2.8 m
	B = 4 - 0.2 = 3.8 m	1	2.8	3.8	0.3	3.19
	For bed room
	L = 3.3 - 0.2 = 2.2 m
	B = 4 - 0.2 = 3.8 m	1	2.2	3.8	0.3	3.76
	For living
	L = 4 = 0.2 = 3.8m
	b = 3.5 - 0.2 = 3.3 m	1	3.8	3.3	0.3	3.76
	2.murrum
	For kitchen
	L = 3 - 0.2 = 2.8 m
	B = 4 - 0.2 = 3.8 m	1	2.8	3.8	0.2	2.13	7.15 m3
	For bed room
	L = 3.3 - 0.2 = 2.2 m
	B = 4 - 0.2 = 3.8 m	1	2.2	3.8	0.2	2.51
	For living
	L = 4 = 0.2 = 3.8m
	b = 3.5 - 0.2 = 3.3 m	1	3.8	3.3	0.2	2.51

	3.pcc
	For kitchen
	L = 3 - 0.2 = 2.8 m
	B = 4 - 0.2 = 3.8 m	1	2.8	3.8	0.1	1.06	3.56 m3
	For bed room
	L = 3.3 - 0.2 = 2.2 m
	B = 4 - 0.2 = 3.8 m	1	2.2	3.8	0.1	1.25
	For living
	L = 4 = 0.2 = 3.8m
	b = 3.5 - 0.2 = 3.3 m	1	3.8	3.3	0.1	1.25

4	DPC
	Long wall
	(ABC,DEF)
	L=6.96 +0.43 = 7.33 m	2	7.33	0.43	_	6.35	14.94 m2
	(GH)
	L = 4.23 + 0.43 = 4.66m	1	4.66	0.43	_	2

	Short wall
	(AD,BE,CF)
	L = 4.23 - 0.43 = 3.8 m	3	3.8	0.43	_	4.9
	(DG , HI)
	L = 3.73 - 0.43 = 3.3 m	1	3.3	0.43	_	2.84

	Deductions
	Door	3	0.9	0.43		1.16

5	Brickwork in superstructure
	Long wall						36.96 m2
	(ABC,DEF)
	Step 1
	L= 6.96 + 0.75 = 7.71m	2	7.71	0.75	0.4	4.63
	Step 2
	L = 6.96 +0.6 = 7.56 m	2	7.56	0.6	0.55	4.99
	Step 3
	L = 6.96 +0.43 = 7.39m	2	7.39	0.43	0.85	5.4

	Long wall
	(GH)
	Step 1
	L = 4.23 +0.25 =4.98m	1	4.98	0.75	0.4	1.49
	Step 2
	L = 4.23 + 0.6 = 4.89 m	1	4.89	0.6	0.55	1.59
	Step 3
	l= 4.23 +0.43 = 4.66m	1	4.66	0.43	0.85	1.7

	Short wall
	(AD,BE,CF)
	Step 1
	l= 4.23 - 0.75 = 3.48m	3	3.48	0.75	0.4	3.13
	Step 2
	l= 4.23 - 0.6 = 3.63m	3	3.63	0.6	0.55	3.59
	Step 3
	l= 4.23 - 0.43 = 3.88	3	3.88	0.43	0.85	4.17

	Short wall
	(DG,HI)
	Step 1
	l= 3.73 - 0.75 = 2.98m	2	2.98	0.75	0.4	1.79
	Step 2
	l= 3.73- 0.6 = 3.13 m	2	3.13	0.6	0.55	2.07
	Step3
	l = 3.73 - 0.43 = 3.3m	2	3.3	0.43	0.85	2.41

By centre line method,

Length centre line plan = 2 x 3.23 +2 x 3.73 +3 x 3.73 +4.23 +2 x 3.73

= 38.3m

Total length = length of centre line plan – n x 0.5 x width

= 38.3 – 4 x 0.5 x width

= 38.3 – 2 x width

1	Earthwork in excavation
	L = 38.3 - 2 x 1 = 36.3	1	36.3	1	1.2	43.56

2	PCC
	L= 38.3 - 2 X 1 = 36.3	1	36.3	1	0.15	5.14
3	Brickwork in foundation
	Step 1
	l = 38.3 - 2 x 0.75= 36.8	1	36.8	0.75	0.4	11.01	36.96 m3
	Step 2
	l= 38.3 - 2 x 0.6 = 37.1	1	37.1	0.6	0.55	12.24
	Step 3
	l = 38.3 - 2 x 0.43= 37.45	1	37.45	0.43	0.85	13.68

4	DPC
	L= 38.3 - 2 x 0.43 = 37.48	1	37.44	0.43		16.1	14.94 m2

	Deduction
	Door	3	0.9	0.43		1.16

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