M Rafique QSEV DMCE AIROLI AIM OF THE SUBJECT: … · III. office rent Job over heads ... II....

M Rafique QSEV DMCE AIROLI

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AIM OF THE SUBJECT:

1. To make the student able to estimate the property.

2. To make the student able to evaluate the property (old and new)

3. To draft the tender documents.

OBJECTIVES:

1. To carry out the market survey for rates of materials and item.

2. To study the rate analysis.

3. To study the specifications.

4. To study techniques of valuation and depreciation.

5. To study the Tender and contract procedures.

INTRODUCTION OF SUBJECT QUANTITY SURVEY, ESTIMATION AND VALUATION

QUANTITY SURVEY means careful study and examination of various quantities (i.e., taking out

quantity from drawing and design)

Survey means a detailed critical inspection. Survey is the act of looking or seeing or observing.

(Study, examine, look over carefully or inspect)

Quantity means how much something is there. Quantity is product of dimension of an item.

ESTIMATION means process of calculating the quantities and cost of various items required in

construction.

VALUATION means assessing the present fair value of a property (structure + land) at a particular

time.

In this subject a large number of topics have been covered. It includes:

1. Estimates, types and methods

2. Rate analysis

3. Specification

4. I S : 1200

5. Tenders and Contract

6. Acts

7. Valuation

8. Types of property (freehold, leasehold)

9. Bar bending schedule

10. Estimation of earthwork, mass haul diagram

OUTCOME OF THE SUBJECT

After studying these topics students will be able to prepare approximate estimate, detailed estimate.

He can draft specifications, tender documents. He can prepare and check. R.A. Bills etc.

Question : Identify the various items of work involved in construction of RCC framed structure and

LBS

I S : CODE:

1. I S : 1200 (Method of measurement of building and civil engineering works)

2. SP : 27 (Handbook of method of measurement of building works)


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3. I S : 3861 (Method of measurement of plinth, carpet, and rentable areas of building)

4. I S : 7272 (Recommendation for labour output constants for building works

5. I S : 2502 ( Code of practice for fixing and bending of bars in reinforced concrete - Detailing)

Role of Quantity Surveyor

A quantity surveyor and estimator is a professionally trained, qualified and experienced person,

dealing with construction of different building, cost, management and communication.

He is appointed on behalf of his employer, whose main task is to ensure that the project is kept within

the agreed budget.

The contractor is also needs services of quantity surveyor for claims for variations in the work and

their settlement.

The quantity surveyor’s role is connected not only with estimate but also the building economics.

Roles of a quantity surveyor are as follows:

1) Preparing the estimate or cost of work to be done by co-relating drawing and specification.

2) Analyzing the rates of items with reference to rate s of materials, labours, hire charges of

machineries and equipment in the locality.

3) Scrutinizing the rates quoted in the tender by different contractors.

4) Measuring the work done, checking RA bills.

5) Analyzing the actual costs with estimated costs, material requirements and finally collecting the

data which will be guide lines for similar type of building.

6) Estimating the cost of work actually carried out.

7) Preparing the bill of quantity (BOQ) and tender document before tendering.

8) Assessing the extra cost due to special features.

9) Preparing the cash-flow statement during construction.

10) Preparing the final account on completion of the project.

11) Value engineering- guiding the architect while preparing the appropriate specification suitable

to soil, climate and functions.

12) Assisting the architect, client in cost planning, preparing of financial statements, cost fore-

costing, settlement of contractors claim and final accounts after completion of work.

GENERAL ITEMS OF WORK INVOLVED IN CONSTRUCTION OF A BUILDING:

Principle units for various item of work:

Principle unit for any item depends upon the nature of work.

Sl no Nature of work Principle unit

1 Voluminous, thick, mass M3

2 Surface work i.e. thin and shallow M2

3 Long and thin Rmt.

4 Steel work Kg

5 Piece or job work number

Unit of various items of work


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Sl no Item unit

Desired accuracy in measurement or limits of measurement (according to SP: 27-1984

1) Dimension shall be measured to the nearest of 0.01m except the following

a. Thickness of RCC slab – measured to the nearest of 0.005m

b. Woodwork – measured to the nearest of 0.002m

c. Structural steel works—to nearest of 0.001m

d. Reinforcement work

e. f. g.

h.

i. j. to nearest of 0.005mthickness of road work (<20 cm) – nearest to 0.005m

2) Area:

a. area shall be worked out to the nearest 0.01 m2

b. for steel work area—to nearest of 0.001 m2

c. volume or cubic content: shall be worked out to nearest of 0.01 m3 except woodwork

which shall be worked out to nearest of 0.001 m3

d. Weight shall be worked out to nearest of 1 kg.

e. Rates shall be worked out upto two places f decimal.

Conversion of Units from MKS to FPS and vice versa:

Density of materials used in Construction:

Thumb Rules for calculating the approximate quantity of steel:

Weight of Tor steel per running meter (Dia.)2 /162

SOURCES OF RATES:

1. Prevailing market rate, 2. DSR & 3. Rate analysis


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Labour Requirement and Labour rate (for rate analysis)

Sl.no. Item Unit Labour required in days (8 hr.)

Head

mason mason Mazdoor Carpenter Fitter Painter Polisher

1

Excavation in ordinary

soil-lift 1.5m,lead 30m

10 cum 3.25

2 Excavation in hard soil 10 cum 7.75

3 Filling or back filling 10 cum 2.33

4 PCC machined mixed in foundation

10 cum 0.25 2.5 14

5

Cement concrete for RCC work for wall, columns, beams, slab

10 cum 0.5 3 23

6

Centering and shuttering for flat

surface

10 cum 4 3

7 Reinforcement work for RCC

100 kg 1 1

8 2.5 cm thick cement concrete DPC

100 sqm 0.5 8 9

9

Brickwork in foundation

and plinth

10 cum 0.5 8 16

10

1st Class BBM in super

structure in Ground floor

10 cum 0.5 8 16

11 1st BBM in First floor 10 cum 0.5 9 20

12

Half brick wall (without

hoop iron)

10 sqm 1.2 2.1

13 UCR stone masonry 10 cum 0.5 10 19

14

Precast Terrazo tiles to

floor

10 sqm 0.1 2 2.1 6.5

15 12 mm thick plastering 100 sqm 0.5 10 15

16

6 mm thick cement

plaster to ceiling

100 sqm 0.5 10 12

17 20 mm thick plaster in two coats

100 sqm 0.5 13 19.5

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White washing or

colour washing two coats with one coat of primer

100 sqm 2 1.5

19

Distempering two coat with one coat of primer

100 sqm 2.5 2.5

20

Ceramic tile flooring

laid over 25 mm thick base in cm 1:6

100 sqm 1 20 21


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Task work / Out turn work: Quantity of work which can be done by a skilled labour of the trade

working for 8 hours a day. Task work does not mean that the quantity of work can be completed only

by the labour as designated. But other types of labours or helpers are also to be engaged to complete

the quantity of work. For example, a Mason can complete 1.5 cum of brickwork per day (8 hrs a day)

provided he is helped by 2 mazdoors to carry and mix the ingredients of mortar and also to carry and

place all other materials at his disposal etc. instructions from a Head Mason for a few hours is also

necessary to complete the quantity of brickwork

RATE ANALYSIS

The determination of rate (correct and reasonable) per unit of a particular item of work is called as

rate analysis.

The above rate is determined by following its specification, detailed survey of materials, labours,

T&P etc. as required and their prevailing rates.

PURPOSE OF RATE ANALYSIS:

1) To find the current rate per unit of an item at the locality.

2) To check viability of rates offered by contractors.

3) To calculate the quantity of materials and labours required for project planning.

4) To decide or fix up the labour contract rate.

HOW TO FIX UP RATE PER UNIT OF AN ITEM:

The following five sub-heads are estimated and summation of these gives the rate per unit of item.

1) Quantity of materials and cost of material

2) Number of labour and rates of labours

3) Cost of equipment or T&P

4) Contingencies, water charges

5) Over head or establishment charges and contractors profit

FACTORS AFFECTING THE RATE ANALYSIS;

1) Major factors

a. cost of materials

b. cost of labours

c. specification

2) Minor factors

a. T&P

b. Over head charges

c. Contractors profit

COST OF MATERIALS:

Material is the major part required for construction work. About 50% of total cost of work is due the

cost of materials. Hence, it is necessary to work out the exact quantity of materials required.

Cost of materials includes original cost, freight, transportation, sales tax and insurance etc.


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COST OF LABOUR

About 30% of total cost of work is due to cost of labour.

Hence, the number labour required for the work shall be worked out correctly.

The rates of labour vary from place to place.

SPECIFICATION

It indicates the quality and proportion of material, the method of construction and protection of work.

TOOL AND PLANTS

Different types of tool and plants are necessary of execution of work.

A good estimator will decide whether purchasing is more economical or hiring is advisable.

OVER HEAD CHARGES (General over head and Job over heads)

General over heads include general expenses to maintain the main office of the contractor such as

I. Salaries of office staff

II. Stationery articles, printing, postages etc.

III. office rent

Job over heads include expenses directly incurred to project such as

I. Salaries of technical, non-technical persons engaged for the work

II. temporary shed and godown rents

III. small tools as the contractor provide for his workmen

IV. repair and depreciation for tools and plants

V. lighting at site

VI. Public relation

VII. labour welfare

VIII. Insurance etc.

Contractors profit:

Generally a profit of 10% should be considered reasonably for ordinary contracts after allocating all

charges of equipments and establishment etc.

For small job-15%

For large job—8% reasonable

FORMAT FOR RATE ANALYSIS:

Consider First 10 cubic meter Unit- cum.

Sl no

Particulars Quantity Unit Rate Amount

1 Material

2 Labour

3 Contingencies, T&P and Water

charges @1.5%

4 Profit and overheads 10%

Total =


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Therefore Rate per cubic meter =

IS-1200 (part 1 to 28 )

Measurement plays a very important role in planning and execution of any civil engineering work

from the time of first estimate to final completion of project. It is also important for settlement of

payment of the project.

It is observed that different government department follows their own mode of measurement. This

may differ from one department to another. Even, mode of measurement in state differs from other in

the country. This different mode of measurement may create disputes in measurement between the

contractor and the owner. Thus to bring the uniform mode of measurement throughout the country

and all government department, the IS-1200 were introduced.

The IS-1200 covers the method of measurement, unit of rate for payment for different items of works

and materials in building and civil engineering works.

The IS-1200 was first adopted in 1964 by the Indian Standard Institution, after the draft finalized by

the civil works. Measurement sectional committee had been approved by the civil engineering

division council.

Is-1200 describes the general rules of measurement regarding,

how to club the items ( i.e. clubbing of

items)

bill of quantity / items of works

description of items

booking of dimension

measurement in stages

rules for deductions etc.

unit of measurement

For example,

Is-1200 part II describes the general rules for measurement of concrete works as follows,

Clubbing of items:

o Items of similar description may be clubbed together

Bill of quantities / items of works:

o Items of works shall fully describe the materials and workmanship to represent work

to be executed

Description of material

o The description of each material shall include where necessary, all charges for storing,

delivery, handling, unloading, conveyance etc. and labour for fitting, fixing in

position, finishing to required shape and size.

Desired accuracy in measurement

o All work shall be measured as follow

o Dimension shall be measured to nearest 0.01m except for thickness of slab which shall

be measured to nearest 0.005m


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o Areas shall be measured to nearest 0.01m2

o Cubic content shall be measured to nearest 0.01 m3

Booking of dimension

o Order shall be consistent and generally in sequence of L x B x D

Work shall be measured separately in a) under water, b) in liquid mud, c) under position, d)

under tides, e) in snow

Measurement in stages

o Work shall be measured under the following categories in convenient stages stating

the height or datum

o Below ground level / datum level

o Above ground / datum level

Unit of measurement

o Work shall be measured in cum.

Rules for deductions as per IS-1200:

1) Rules for deduction in masonry (i.e. for brickwork and UCR)

No deduction shall be made for the following:

a. Opening upto 0.1 sqm.

b. Ends of beams, posts, rafters, purlins etc.

c. Wall plates, bed plate, bearing of slab, chajjas, where thickness does not exceed 10 cm

and bearing does not extend over full thickness of wall.

d. Cement concrete block for holdfasts and holding down bolts.

e. Iron fixtures like holdfasts for doors and windows pipe upto 300 mm dia.

2) Rules for deduction in plastering work:

a. No deduction shall be made for ends of beams, posts, rafters etc.

b. No deduction shall be made for opening upto 0.5 sqm. And no addition shall be made

for jambs, soffit, sills of these opening

c. For opening between 0.5 to 3 sqm. And when both faces are plastered with the same

plaster, deduction shall be made for one face only and no addition shall be made for

jambs, soffit and sill etc.

d. For opening between 0.5 to 3 sqm. And when one face is plastered, deduction shall be

made for 50% of one face only (i.e. half deduction) and no addition shall be made for

jambs, soffit and sill etc.

e. For opening of area exceeding 3sqm. deduction shall be made for opening on each

face, and jambs, soffit and sill shall be added.

3) RCC work:

No deduction shall be made for the following:

a. Volume occupied by the reinforcement

b. Pipe conduit etc. not exceeding 100 sqcm in cross sectional area.

c. Opening upto 0.1 sqm.

d. Ends of dissimilar materials ( like girders, beams, rafters, steps etc.) upto 500sqcm

e. Chamfers, splays, grooves, and rebates

f. Small voids not exceeding 40 sqcm

4) Form work:

a. No deduction shall be made for opening upto 0.4 sqm.


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b. Form work of secondary beams shall be measured upto the sides of main beams, but no

deduction shall be from the form work of main beam intersects it.

c. No deduction shall be made form work to stanchion or column casing at intersection of

beam.

d. Raking of circular cutting and rounded or moulded edges shall be measured in rmt.

e. Moulded stopping shall be enumerated.

Some Terminologies:

Covered area

It is the ground area covered by the building immediately above plinth level. It doesn’t include the

watchman’s cabin, pump house, garbage shaft, electric cabin etc.

Plinth area:

This is the built-up covered area measured at the floor level of the basement or at any storey.

The following shall be included in the Plinth area.

Area of wall at floor level excluding plinth offsets, if any

Internal shaft of sanitary installation (A should not be greater than 2 sqm.). AC duct, lift,

machine room etc.

Porch area other than cantilever

The following shall not be included in plinth area:

Area of loft

Balcony

Area of architectural features

Cantilever porch

Spiral staircase including landing

Terrace at floor one

Floor area:

This is useable covered area of the building at any floor level.

Floor area = plinth area – area of walls

The following shall be included in wall area

Doors and other opening in the wall

Internal pillars and supports


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Plaster along walls exceeding 300sqcm in area

Carpet area:

This is the floor area of the useable rooms at any floor level.

Carpet area = floor area – following i.e.

Verandah

Corridors, passages

Kitchen, pantry

Stores in domestic building

Entrance hall and porches

Staircase and mumty

Shaft for lifts

Garages

Barsaties (i.e. covered space open at top

at least one side, constructed on a terrace

roof used for shelter during rains)

Canteens,AC ducts, AC plant room

Rentable area:

For residential building, the area shall be the carpet area along with the following,

The carpet area of kitchen, panty, store, lavatory, bathroom and

50% of carpet area of unglazed and 100% of glazed verandah

Contingencies:

There are always some items of work which are unforeseen and can not be reasonably predicted

during the preparation of estimate. To meet up such unforeseen expenses an additional amount of 3 to

5% of the estimated cost of work is provided in the total estimate. This addition cost is known as

contingencies.

e.g. i) nosing in steps

ii) moulding

Work charged establishment

It is the establishment which is directly charged or employed for execution of the work. It is a

temporary establishment. It includes work charged staff, departmental store (site store), and

machineries in connection with the specific work. Work charged establishment may include technical

and non-technical staff. for such work charged establishment, an additional amount 2 to 2.5 % of the

estimated cost is provided in the total estimate. General the appointment of such staff is made on

temporary basis according to progress of the work.

T&P:

For big projects, it becomes necessary to use special type of tools and plants. These tools and plants

are not for general use. Their cost is born by the work concerned.

Such T&P may be batching plant, transit mixer, dumpers, cranes etc.

So in order to purchase such type of special T&P, an amount of 1 to 2.5% of the estimated cost is

provided in the total estimate.

Lump sum item:

The item of work which can not be easily measured or assessed during its execution is called as


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lump-sum item

Lump-sum rate is provided for such j\items in the estimate.

Examples of lump-sum item

Work of site cleaning

Dewatering

Removing roots of a tree etc.

Departmental charges or centage charges

Prime cost:

Prime cost is the actual cost or articles at shop. It refers to the supply if article only and not to the

carrying out of work. It is not always possible at the time of preparing the estimate and even when

entering contract, to specify exactly the type of article required. For example, water supply fitting,

sanitary fittings, door and window fittings etc. are to be decided during the time of actual fitting

according to the owner’s choice or engineer-in-charge.

For the execution of such item reasonable amount is kept in the estimate as prime cost.

Contractor is not allowed any profit on the prime cost articles but he may be allowed actual cost of

carriage, if specified.

Provisional sum

Provisional sum is the amount provided in the estimate for some special work, whose details are not

known at the time of preparing the estimate. Such special works are,

Installation of lift

Shifting of water lines, sewer line or electric line etc.

Service pipe connection to main water line.

Day work:

The term Day work is used to denote the procedure of costing an item of work on the basis of actual

labour and material required.

Certain item of work which cannot be measured such as, architectural works, dismantling partition

under water, taking out the roots of trees during excavation etc, are included in day work.. These are

paid for on the basis of the actual quantity of material and labour hours required to complete the ob

and are denoted as day work

A list of labour engaged and their rates are recorded. Similarly a list of material required for the work

is prepared. The prices are to include cost of material, labour, overheads, supervision and profit.

Piece work:

Bill of quantity (BOQ) or schedule of quantities:


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BOQ is a complete list of all items of work involved in connection with the estimate for a project

with description, quality and unit rate against each item of work.

These are filled up in a tabular form similar to the abstract of estimated cost but the rate and amount

column remain blank. Such BOQ is provided in tender form for item rate tenders. Contractors put up

their own competitive rates and calculate the totals to offer their estimated amount to complete the

whole work. The BOQ is also required to calculate the quantities of different materials required for

the project.

Schedule of rates

Schedule of rates are those list of rates which help in preparation of estimate. The also serve as guide

in setting rates in connection with contract agreements. They are prepared on the basis of the rates

prevailing in each locality including the cost of transport and profit.

All rates should be inclusive labour, materials, octroi, local charges, income tax, sales tax, royalties

etc.

They should be maintained and kept up to date by different engineering department or authorized

organization, in the form of a printed book known as Schedule of Rate Book.

Administrative approval:

For any work or project required by a department, an approval or sanction of the competent authority

of the department, with respect to the cost and the work is necessary at first instance.

The formal acceptance of the proposal by the competent authority of the administrative department is

termed as administrative approval

For this, approximate estimate and preliminary plans are submitted by the engineering department to

the administrative department to abating the administrative to take up work within the sanction

amount.

After the administrative is given, the engineering department take up the work and prepares the

detailed designs, drawings and estimate and then execute the work.

Technical sanction:

It means the sanction of detailed estimate. Design calculation, quantities of works, rates and cost of

the work by the competent authority of the engineering department. After the technical sanction is

given, then only the work is taken up for execution.

Technical sanction ensures that the proposal is structurally sound and the estimate is accurately

calculated based on adequate data.

Expenditure sanction:

It means the consent of government in the expenditure proposed. The expenditure is sanctioned by

the finance department on the basis of administrative approval and sanctioned detailed estimate. This


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is an allotment of fund to meet up the expenditure to execute a work.

ESTIMATE

Introduction:-

An estimate is the process of calculating the quantities and cost of the various items required in

connection with the work for its satisfactory completion.

To prepare an estimate for any construction work, the things required are,

Drawing: Drawing should consist of plan, elevation and section through important points.

Specification: specification should be in details. It should be specific description of all

workmanships, quality, properties, proportion of materials and method of construction.

Rates: rates should be prevailing market rates.

Purpose of estimating:

1. To know the amount required to complete the work.

2. To know the quantity of materials

3. To know the labour required

4. To know the requirement of T&P, equipment

5. To fix up the completion period from the volume of works involved in estimate

6. To prepare the construction schedule and programme. Also to arrange funds required according

to the programme.

7. To invite tender

8. For valuation of existing property

9. To justify the investment from benefit-cost ratio

Types of estimate:

1) Approximate estimate:

a. Plinth area method

b. Cubic content method

c. Approximate quantity method

d. Service unit method

e. Typical bay method


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f. Cost comparison method

g. Elemental bill method

h. Use of CBRI equations

2) detailed estimate:

a. Item rate estimate

b. Revised estimate

c. Supplementary estimate

d. Revised and supplementary estimate

e. Maintenance and repair estimate

Approximate estimate ( or preliminary or rough or abstract estimate):

This is an estimate to find out the approximate cost in a short time. It enables the concern authority to

know the financial aspect. Such an estimate is prepared from practical knowledge and cost of similar

works.

For this estimate, detailed surveying, design and drawings are not required.

A line sketch of project according to its requirements may be required.

Approximate estimate for main parts of a project are made separately.

This estimate is accompanied by a brief report explaining the necessity and utility of the project and

showing how the cost of separate items has been arrived at.

(Main item like cost of land, cost pf building, cost of road, water supply, sanitary works,

electrification etc.)

This is also accompanied with site plan or layout plan. Provision of contingencies @ 5 to 10 % is

added with the abstract which is the total approximate cost of project.

Importance of approximate estimate:

The importance of approximate estimate should not be neglected. Because if there is large difference

between the approximate and the cost of construction of a project, this may misguide the intention to

understand the project.

In case the approximate estimate cost is too high, the project may be left without preparing its

detailed estimate

If the approximate estimate is too low and in later stage, when it is found that the actual estimated

cost is much higher than the approximate estimate, then the project may be cancelled due to lack of

fund.

Hence to make the approximate estimate close to the cost of construction, practical knowledge, upto

date records of rates and approximate method of estimate are essential.

Importance of approximate estimate is obvious.

Under-estimating may result in the client getting an unpleasant shock when tenders are opened and

drastically modifying or abandoning the work at that stage.

Over-estimating may lose the engineer his client or his job or in any case his confidence.

Purpose of approximate estimate:


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Approximate estimate is worked out before preparation of detailed estimate of a project. It serves

mainly the following purposes.

To know the feasibility of the project

To save time and money.

To obtain administrative approval.

For insurance and tax schedule

For planning the project

To know the benefit- cost ratio.

To give a rough idea of the probable expenditure.

Plinth area rate method:

Plinth area estimate is calculated by finding the plinth area of the building and multiplying by the

plinth area rate.

The plinth area rate is obtained from the cost of similar building having similar specification, height,

and construction in the locality.

The plinth area should be calculated for the covered area by taking the external dimension of the

building at the floor level. Courtyard and other open area should not be included in the plinth area.

For multistoried building, the plinth area estimate is prepared for each storey separately.

If the plan of the building is not ready or available, floor area of rooms, etc. may be determined from

requirements, and 30 to 40 % of the total area thus found, may be added for walls, circulations to get

the approximate plinth area.

For example:

Cube rate method ( cubic content method):

This is an approximate method. It is more accurate than plinth area estimate.

This estimate is calculated by finding the cubical content of the building [LXBXD] and multiplying

by the cube rate.

The length and breadth should be taken as the external dimensions of the building at the floor level

and the top of roof. ( or half way of the sloped roof)

The foundation and plinth and the parapet above roof are not taken into account in finding the cubical

content [IS-3861].

The cubical rate is obtained from the similar building constructed recently at that locality.

Approximate quantity method:

In this method approximate total length of wall is found in running meter. And this total length is

multiplied by the rate per running meter of wall, which gives a fairly accurate cost.

For this method, the structure may be divided into two parts.

Below plinth [ foundation + plinth]

Above plinth [superstructure]

The running meter cost below plinth including the cost o excavation, foundation, plinth, and DPC.

Similarly, the running meter cost for super structure includes the cost of brickwork, floors, roofs etc.

For this method the plan or line plan of the structure should be available.


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Service unit method:

In this method, all cost of a unit quantity such as per km of road, per m of span for a bridge, per

classroom, per student for school building, per bed for hospital, per liter for water tank, per seat for

cinema hall etc. are considered first and approximate cost is prepared by multiplying the cost per

service unit by the number of units in the structure.

Approximate estimate = number of service unit x cost per service unit.

This estimate can be prepared quickly, but it requires records of the current rate per service unit for

similar designed structures having the same specification at that locality.

Typical bay method:

Bays are compartments or similar portion of a structure. When the area of a structure consists of

similar parts such as godown, a railway platform, factory shed etc. which are constructed with

intermediate columns or with roof trusses on walls placed at equal distance forming bays. Bay is a

center to center distance between the supports.

Approximate cost = no of bays x cost of one bay

Cost comparison method:

This method is suitable for preparing approximate for prototype structures or units consisting of

several works after comparing with the past records of expenses for such works.

For example when prototype staff quarter or railway stations etc. are required to be estimated

approximately then the estimate for such prototype works are prepared by comparing the previous

cost with the present market rates, normally by increasing the past cost on a % basis.

Elemental bill method:

i.Elemental bill method:

In this method, a building is divided into a few items of works and measurements are taken out

for the same.

The cost per unit of each group is worked out separately and carefully. The quantities are

multiplied by these rates and the cost is worked out.

The nature of each group or item of work and the total number of items will vary with different

kinds of buildings. For a small work- residential building- the different items to be considered

may be as follows:

i. External walls

External walls including excavation, concrete bedding, brick masonry work, pointing, internal

finishing, doors and windows. Measurements are taken out in square meter (specifying the

thickness of wall)

ii. Internal walls:

Internal wall including all items mentioned under external walls. The unit of measurement is

square meter

iii. Ground flooring :

Ground flooring includes surface excavation, hard murum or rubble soling, floor finishing with

concrete bedding etc.-unit sqm.

iv. Suspended flooring:

Suspended flooring Including RCC slab or other supporting arrangement and floor finishing. -

Unit- sqm.


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v. Stairs:

Complete item may be measured I number of steps, cost of one step being worked separately.

vi. Roof:

Includes a) Trusses, if any, per number, b) Purlin, common rafters, battens and tiles- all these

are measured together in one item. Unit - sqm. Of the roof area

vii. Water supply and sanitary fittings-LS

viii. Electrical work- LS based on past experiences

CBRI equations:

CBRI stands for Central Building Research Institute, (Roorkee).

In this method, approximate quantity of materials and labours required are sqm. Of plinth area, are

calculated with the help of empirical equations developed by CBRI Roorkee and the quantities are

multiplied by the total plinth area of the building.

Therefore, approximate cost = quantity x current rate

CBRI equations are for building of different shapes and plinth area varying from 30 to 300 sqm.

These equations are average constant.

These equations are useful for preparation of building cost index, preplanning of materials, and

labour requirement in a building project.

For example:

For double storied building, materials and labours are calculated as below,

Cement required = )0.145xA+0.54) in Tonne

Steel required = (21.97xA-305) in kg

Similarly, mason required = 1.355xA+36

Mazdoor = 4.91xA+33 etc.

Where A = plinth area in sqm.

Note: i- equations given by CBRI are valid for PA= 30 to 300 sqm.

ii- derived equations are based on particular specifications.

Item rate estimate:

It is an accurate estimate. In the estimate the quantities and cost of each item of work are worked out.

The length breadth and height of each item are taken out correctly form drawing and quantities of

each item are calculated and then abstracting and billing are done.

The detailed estimates are done in 2 stages:

Detailed of measurement and calculation of quantities

Abstract of estimated cost

The cost of each item of work is calculated in a tabular form, from the quantities already computed.

And the total cost is worked in abstract of estimate form.

The rates of different items of work are taken as per schedule of rate or current workable rate are

analyzed rate fro finished item of work.

The provision for contingencies (3%) and work charged establishment (25) are made.

The grand total thus obtained gives the estimated cost of work.

The detailed estimate is accompanied with:


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Report

General specification

Detailed specification

Drawing-plan, elevation, section

Site plan or layout plan or index plan etc.

Calculation and design

Analysis rate, if rates not as per schedule of rate., or for the non-schedule item

Detailed estimate is prepared for technical sanction of the competent authority, for arranging

contract (i.e.) for execution of work.

Measurement sheet

Item no. Particulars No. L B H/D Quantity remarks

1

2

Abstract sheet

Item no. Particulars Quantity unit rate amount remarks

1

2

Total = Rs.

Add for contingencies @5%

Add for contingencies @2.5%

Grand Total =

Revised estimate:

It is a detailed estimate. It is required to be prepared under anyone one of the following conditions:

When original sanction estimate is exceeded or likely to exceed by more than 5%.

When the expenditure on a work exceeds or likely to exceed the amount by more than 10%

When there are material deviations from the original proposal.

When it is found that the sanctioned estimate is more than the actual requirement.

This estimate is accompanied with a comparative statement, abstract form, rate and amount

for each item of work of the project as compares with the original estimate side by side stating

the reasons of variations.

A revised estimate is prepares and submitted for fresh technical sanction.

Supplementary estimate:

While a work is in progress, some changes or additional works due to material deviation of a

structural nature from the design originally approved may be thought necessary for development of a

project. An estimate is then prepared to include all such works. This is known as supplementary

estimate.

This estimate is accompanied by a full report giving its necessity.

The abstract must show the amount of original estimate and the total of sanction required including

the supplementary amount.


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Combination of revised and supplementary estimate:

During execution of project, it may be necessary to revise the original estimate due to increased

volume of original proposed work and at the same time sanction of supplementary works.

For such a case a revised estimate is prepared for the increased volume of original work and a

detailed estimate for the supplementary works not included in the original schedule. The amount of

supplementary estimate is added to the revised estimate, showing the amount separately. Thus the

total amount for supplementary works also.

Comparison of revised and supplementary estimate:

Sl. No. Points Revised estimate Supplementary estimate

1 Conditions

where

necessary

This estimate is required when the

sanctioned amount is exceeded due

to change of rate or addition of work

fairly dependent on the work at first

sanctioned. So revised estimate is

due to material deviation from

original proposal.

This is required to supplementary

works which are fairly independent

of the work at firs sanctioned. So

supplementary estimate is due to

material deviation of a structural

nature from the design originally

approved.

2 Comparative

statement

It is accompanied with a

comparative statement in an abstract

from showing the probable

variations for quantity, rate and

amount against each item of work

involved in the project.

No comparative abstract form is

required. This is an estimate for

additional work only. The abstract

shows the original estimate and the

total amount of the sanction

required including supplementary

amount.

3 Need of

drawing

Revised estimate is required due to

change of rate or quality of

materials, so revision of drawing is

necessary.

Supplementary estimate is

required due to some new works

or due to change of design, so

addition or revision of drawing

may be necessary


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Annual maintenance and repair estimate:

After completion of a work it is necessary to maintain same for its proper function and for the same,

an estimate is prepared for the item which requires renewal, replacement, repairs etc. in the form of

detailed estimate.

Complete estimate:

This is an estimated cost of all items which are related to the work in addition to the main contract or

to the detailed estimate.

The complete estimate includes the following:

1. cost of land

a. actual cost of land

b. cost of surveying

c. cost of examination of deeds, title of land and execution of deeds

d. Defaulting taxes of land, title of land, street improvement if any.

2. cost of legal expenses required between the owner and the contractor

3. cost of main contract or material, labour and supervision

4. contingencies 5% for extra works

5. engineering fees

a. cost for preparation of plan, design, estimate and sanction

b. cost for supervision of works

6. permit fee for water and electricity during construction

7. misc. expenses like transportation cost of owner with his party.

Complete set of estimate:

A complete set of estimate is set of documents which are prepared for submission to the government

to obtain its sanction.

A complete set of estimate shall essentially consists of the following:

1. Title page: indicating the name of engineering department, circle, division, name of work, and

total estimated amount.

2. index of contents

3. reports

4. design data design calculation

5. specification

6. detailed statement of measurement, quantities and rates

7. analysis of rate of unscheduled items

8. detailed estimate in specified form

9. an abstract of estimate showing the total estimated cost for all items, contingencies, work

charged establishment, T&P, department charges

10. general abstract ( in case of several units of works under a project )

11. drawing consisting plans, detailed drawings, site plan, index plan etc.

Approximate cost for water supply, sanitary and electrification works:


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In total estimate of a building, cost of water supply, sanitary and electrification works are also

required.

Provisions for above works are usually made on the basis of percentage of the building cost.

When external services for water supply pipe line, sewer line and electric line runs abutting a

building, in that case provision for internal services should be considered as below.

1. water supply---- 4 to 5 % of building cost

2. sanitation ---- 4 to 5 % of building cost

3. electrification---- 9 % of building cost

4. approach road, boundary walls etc.---- 5 % of building cost

5. architectural treatment etc.---- 1 % of building cost

Steps in calculation of approximate estimate:

1. plinth area = carpet area + circulation area + area occupied by walls

a. circulation area = 20% of Plinth area

b. area occupied by walls in frame structure = 8% of the floor area

c. area of wall s in load bearing structure = 15 to 17 % of floor area

2. cost of super structure = plinth area x cost of construction for superstructure

3. building cost = cost of super structure + cost of foundation

4. cost of foundation = 20% of cost of super structure

5. Cost of other building services like, water supply, sanitation, electrification, architectural

treatment, approach road and boundary walls etc.

6. total

7. add for

a. contingencies @ 5%

b. work charge establishment and contractors profit @ 5%

8. grand total

Numerical on approximate estimate:


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Methods or procedures of taking out quantities for various items of work:

For the accurate estimate the dimensions, length, breadth and height or depth are taken out correctly

from drawing.

For accurate estimate, junctions of wall require special attention.

Long and short wall method:

Steps:

1. draw the centerline plan

2. consider wall spanning in horizontal direction as ‘ Long wall’ and vertical wall as ‘ short

wall’

3. calculate c/c length of long wall and short wall

4. calculate length of long wall = c/c length of long wall +1/2 * LHS short wall width+ ½ *RHS

short wall width

5. OR length of long wall = c/c length of long wall + width of short wall [if LHS and RHS

width is same]

6. calculate length of short wall = c/c length of short wall – width of long wall

7. quantity = LXBXD IN CUM.

Center line method:

STEPS:

1. draw center line plan

2. calculate the total length of center line for main wall

3. calculate number of T- junction carefully for main wall

4. calculate the total length of center line for partition wall (thickness = 100 mm )

5. calculate number of T- junction carefully for partition wall

6. calculate the total length of center line for verandah wall

7. calculate number of T- junction carefully for verandah wall

8. calculate length of item = L

9. L = c/c length – no of T-joints * ½ * width of item at this level

10. quantity = L * B * H

11. take no. of junction for wall meeting from 3- direction = 1

12. take no. of T- junction for wall from four direction = 2

Crossing method:

In this method, first the over all perimeter of the building is calculated. Then four times the thickness

of the wall is subtracted from perimeter to get the center line length.

Internal walls are grouped separately to their sections and measured in between the internal faces of


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the main wall at that level.

MASUREMENT OF STEEL WORKS:

In RCC works steel reinforcement may be used in the form of:

plain mild steel bars

deformed bars

cold twisted bars

TMT (Thermo Mechanically Treated) bars

Hot drawn steel wire ( mostly used in prestressed concrete

Plain round MS bar is denoted by Ф

Cold twisted deformed or Tor steel bar is denoted by the symbol Ф

Development length (Ld):

Tensile force = Bond resistance

Lap length:

During placing of steel for RCC structure, if the requires length of bar is not available then lapping

i.e. placing tow bars side by side for a designed length is done. This designed length is the

development length.

Lap length in compression should not be less than 24 dia.

End anchorage:

An anchorage is generally provided in the form of

Semi circular hook

90 degree bend

45 degree bend

fig.

for Mild steel bar, the bond resistance value of an anchorage is assumed as

16 Ф for semicircular bend

8 Ф for 90 degree bend

12 Ф for 45 degree bend

In case of deformed bars, the value of bond stress for various grades of concrete is greater than

40% than the plain bars. Hence the deformed bars may be used without hook and anchorage,


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provided development length is satisfied.

Hook and bend allowance according to IS 2502- 1963 are as follows

For Tor steel

Minimum hook or bend allowance = 75 mm

Hook allowance = 13 Ф

90 degree bend allowance = 6 Ф subject to minimum of 75 mm

For Mild steel

Minimum hook or bend allowance = 75 mm

Hook allowance = 9 Ф should not be less than 75 mm

90 degree bend allowance = 5 Ф subject to minimum of 75 mm

fig.

Note – Provide lap length = 50x diameter of bar (unless specified otherwise)

Bent up bars:

Fig.

Covers to reinforcement as per IS-456-2000

Slab - 20 mm

Beam - 20 mm

Column - 20 mm

Footing - 20 mm


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Stirrups:

Fig

Bar bending schedules:

BBS is a list of reinforcement bars in tabular form. It provides the information as shown in the

following table.

BBS

Sl

no.

Particulars Bar

mark

Dia. Shape of

bending

Cutting

length

Lc

No. Total

length

Weight

per rmt

Weight

1

2

3

Purpose of BBS:

1. It is prepared to estimate the quantity of reinforcement.

2. It is prepared for payment of bill.

3. It is prepared to know the requirement of different sizes of bars.

4. It is used for procurement of steel, stage wise.

5. It is used as guidelines for cutting, bending, placing and fixing of bars at site.

6. It is also used for checking of reinforcement at place. Checking becomes easy.

7. It is also used for checking the actual consumption at site.

Problems:

Prepare the BBS for Column footing.

Prepare the BBS for Continuous beams.

Prepare the BBS for Continuous slab.

Prepare the BBS for Portals.

Prepare the BBS for Retaining wall.


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ROAD ESTIMATE:-

Earth work:-

The cross section of earthwork of road in banking or in cutting is usually in the form of trapezium as

shown in the fig.

Fig.

Volume = sectional area x length

And

Sectional area = area of central rectangular portion + area of triangular portion on two sides

= Bxd + 2x 1/2xSxdxd

= Bxd + Sd2

volume = (Bxd + Sd2)xL

Note:

Above formula is applicable when ground is leveled and formation level of road has no

gradient.

S : 1 = H : V means V = 1 and S = H

S : 1is the ratio of side slopes as horizontal : vertical

For 1 vertical, horizontal is S1,

For d vertical, horizontal is Sd,

If side slope is given as 2H: 1V, then S = 2

If side slope is given as 1H : 2V then S = ½ ( divide both sides by 2)

If side slope is given as 1 in n, then S = n (e.g. 1in 100 meaning is for 100 m length, vertical

length is 1 or 100H : 1v so S = 100

when the ground is in a longitudinal or the formation level has a uniform gradient for a length

‘L’/ then the quantity of earthwork may be calculated by any one of following methods

1. Formula of Mid section method:

o V = (B*dm+Sdm2) where dm =(d1+d2)/2

2. Trapezoidal formula or Average End Area method or Mean Sectional Formula method

o Total volume = ½(A1+2A2+2A3+. . . . 2An-1+An)

o Where v=L/2[1st area + last area+2*Σ(other areas)

o A1, A2, A3….etc are the area of consecutive sections and spaced at a common

distance or length.

3. Prismoidal formula or Simpson’s rule for volume.

o V=L/3(1st area + last area +4 * Σ(even areas + 2* Σ odd areas)

o Note that the number of section must be odd to apply the prismoidal formula. In case

of even number of sections, the end strip must be treated separately and the volume of


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the last strip may be calculated by mid section or by prismoidal formula.

4. Mean area method

o V=Am* L where Am= (A1+A2)/2, A1=B*d1+S*d12 , A2=B*d2+Sd2

2

Numerical:

Lead and lift:

Normally earthwork is estimated for 50m lead or distance and 1.5m lift or depth. And this distance of

50m and depth of 1.5m are known as normal lead and lift.

Normal rate for earthwork is for 50 m lead and 1.5 m lift.

For greater lead or lift, the rates will be different ( higher) for every unit of 50m lead and for every

unit of 1.5m lift

The earthwork is therefore, estimated separately for every 50 m lead and for every 1.5m lift.

In other words, the lea shall be a horizontal straight practical distance through which the e earth may

be carried or transported from the sources of to the place of spreading

Lift shall be measured from ground level.

When the earth to be carries over a bank and dumped beyond it, the lift shall be measures in level

between the center of gravity of the excavated earth and the top of bank.

For calculation of earthwork in a road, survey work is carried out. And with the help of survey work,

L-section and cross section of the ground are taken and the formation line is fixed.

The formation level is fixed in consideration of flood level, gradient, height of bank, depth of cutting

etc.

In plain countries, road is usually in banking. In hilly countries, road is usually both in banking and

cutting and the excavated earth from cutting is utilized in banking

Area of turfing or Pitching on sloping surface:

Width of Turfing = sqrt(dm2+S2dm

2) = dm sqrt(1+S2)

Area of side slopes on both faces = 2*L*dm*sqrt(1+S2)

Numerical:


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SPOT LEVELS FOR VOLUME:

To calculate the volume of earth work for large areas or from borrow pits, spot levels, are required.

Spot levels are the levels taken on various selected spots of a ground.

To calculate the volume of earth work, the area is divided into a number of squares or rectangle or

triangle. After this, the original surface levels are taken at each corner of square or triangle or

rectangle. Now, excavation or filling work can be carried.

The divided areas are recorded in the drawing. After completion of earthwork, the divided areas are

again marked on the new surface, and levels are taken at each corner of square, triangle or rectangle.

The difference of levels at each spot gives the depth at that point.

Mean depth is found out for each area (A)

Thus the volume area A1 = A * dm1 = V1

Note:-

If area of blocks are different, then V = A1*dm1 + A2 * dm2 + A3 * dm3

If area of each block is same, then V = area of one block * ∑ dm

MASS HAUL DIAGRAM:

Mass diagram is a curve plotted between distance on x-axis and cumulative volume of cutting and

filling on y-axis.

Any point the mass diagram , represents or indicates the cumulative volume of earthwork (i.e. cutting

or filling)at that point

It also represents the manner in which the earth is to be moved i.e. haul direction

It indicts the balance point of cutting and filling, the volume of free haul, volume of over haul.

Importance of Mass diagram:

The mass diagram is useful in economical planning of earthwork for road project

The mass diagram indicates the haul direction. Hence the economical planning for movement of

materials from cutting to filling can be made. The haul distance can be kept minimal to reduce the

cost of earthwork especially for undulating and hilly area.

Mass diagram determines the movement of earthwork for different leads to use maximum quantity of

excavation in filling embankment.

Mass diagram determine the place of borrow pit

Mass diagram helps in preparing the comparative economical study of between the cost of carried

earth from the cutting and the cost of carried earth from borrow pit


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May-2009-problem:

The GL at various chain ages along the center line of a proposed road are as under:

Chainage 21 22 23 24 25

GL 180.50 183.36 185.52 187.10 186.50

The ground has uniform cross slope of 1 in 8. the chain is 30 m. long. The road formation is proposed

at uniform gradient passing through the GL at end chainages with formation width as 8m. and side

slope of cutting as 1:1.

Estimate the quantity of earthwork for the proposed road section, in a tabular form.

SOLUTION:-

Let us solve this problem by using mean area method, chain = 30 m.

Gradient in formation = (186.50-180.50)/(4*30) = 6/120 = 1/20 i.e. 1 in 20

Therefore for, for 30 rise = 1/20*30 = 1.5m

Other data given, B=8m,’ b=4m, L=30m, S=1, r=8

A = [sb2 +r2*(2*b*d+sd2)]/(r2-s2)

Chainage 21 22 23 24 25

GL 180.50 183.36 185.52 187.10 186.50

FL 180.50 182.00 183.50 185.00 186.50

d 0 -1.36 -2.02 -2.1 0

Chainage d s r A Am L qty

21 0 1 8 0.254

22 -1.36 1 8 13.186 6.72 30 201.600

23 -2.02 1 8 20.816 17.001 30 510.030

24 -2.1 1 8 21.801 21.308 30 639.24

25 0 1 8 0.254 11.028 30 330.84

Total =1681.71 m3


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Terminology:

Haul distance:

Haul distance is the distance to be traveled ta any tome from face of excavation to the tip end of

embankment formed from it.

It is the distance between the place of excavation and place of dumping.

Haul:

Haul is the sum of product of each load or volume by its haul distance

Total haul = ∑ (load * haul distance)

Average haul distance

This is the distance between the center of gravity of cutting and the center of gravity o f deposited

materials.

Free haul distance:

In contract work, the cost of earthwork includes the cost of haul ( i.e. transportation) within a

specified distance ( say, 1km, 5km etc.) and this limit of distance upto which materials is hauled ( i.e.

transported) without any extra cost is known as free haul distance.

Economical haul:

This is the distance within which it is profitable to use the excavated materials from cutting and move

or transport or haul the same in banking i.e. filling.

In other words, this is the limit of profitable haul distance beyond which it is economical to waste the

earth and borrow the earth for banking or filling.

Beyond economical haul,

The cost of excavation + cost of hauling (i.e. transportation) = the cost of excavation + cost of

hauling to waste the earth+( cost of excavation + cost of hauling from the borrow pit)

Over haul:

As we know, in contract work, the cost of earthwork includes the cost of excavation plus cost of haul

(i.e. transportation) within a specified distance which is known as free haul distance.

If the earth is moved or transported beyond this free haul distance, the extra payment is made for the

haulage of each unit.

Thus the haul distance beyond the free haul distance is called as over haul distance. And the sum of

product of volume by the respective over haul distance is termed as over haul.


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Balance line:

A balance line is a horizontal line that intersects the mass diagram in two places.

Between the ends of balance line, the cut volume generated equals the fill volume required.

The exact interpretation of a mass diagram is entirely dependent upon the balancing line.

The position of balance line is adjusted generally near the base line trying to equalize the length of

upward and downward loops as far as possible to show a possible method to reduce haul distance and

borrowed earth.

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