Quantity Surveying/longwall shortwall method/Earthwork- Civil Engineering

BY : AADIL ANSAR
ROLL NUMBER : 14H11A0101
DEPARTMENT OF CIVIL ENGINEERING
AL-HABEEB COLLEGE OF ENGINEERING & TECHNOLOGY

Estimating is the technique of
calculating or Computing the
various quantities and the
expected Expenditure to be
incurred on a particular work or
project.

In case the funds available are less than the
estimated cost the work is done in part or by
reducing it or specifications are altered, the
following requirement are necessary for
preparing an estimate.
• Drawings like plan, elevation and sections
of important points.
• Detailed specifications about workmenship
& properties of materials etc.
• Standard schedule of rates of the current
year.

REQUIREMENTS OF ESTIMATION AND COSTING
• Estimate gives an idea of the cost of the work and
hence its feasibility can be determined i.e. whether
the project could be taken up with in the funds
available or not.
• Estimate gives an idea of time required for the
completion of the work.
• Estimate is required to invite the tenders and
Quotations and to arrange contract.
• Estimate is also required to control the expenditure
during the execution of work.
• Estimate decides whether the proposed plan
matches the funds available or not

PROCEDURE OF ESTIMATING
Estimating involves the following
operations
• Preparing detailed Estimate.
• Calculating the rate of each unit of
work
• Preparing abstract of estimate

DATA REQUIRED TO PREPARE AN ESTIMATE
• Drawings i.e. plans, elevations, sections
etc.
• Specifications.
• Rates

TYPES OF ESTIMATES
• Approximate estimate: It is also known as rough
estimate and it is not accurate. It is useful for
preliminary study of project to finalize the budget .
• Detailed estimate: It is accurate estimate, in which
each item of work is worked out separately in the
prescribed format
• Abstract estimate: It gives an accurate cost of the
project .The cost of each item is calculated with the
quantity in detailed estimate and rate arrived at site
in the prescribed format.

METHODS OF PREPARATION OF APPROXIMATE
ESTIMATE
Following are the methods used for preparation of
approximate estimate.
• Plinth area method
• Cubical content method

METHODS OF TAKING OUT QUANTITIES
The quantities like earth work, foundation
concrete, brickwork in plinth and super
structure etc., can be workout by any of
following two methods:
• Long wall - short wall method
• Centre line method.

LONGWALL-SHORTWALL METHOD
In this method, the wall along the length of room is
considered to be long wall while the wall
perpendicular to long wall is said to be short wall. To
get the length of long wall or short wall, calculate first
the center line lengths of individual walls. Then the
length of long wall, (out to out) may be calculated after
adding half breadth at each end to its center line
length. Thus the length of short wall Measured into in
and may be found by deducting half breadth from its
center line length at each end. The length of long wall
usually decreases from earth work to brick work in
super structure while the short wall increases. These
lengths are multiplied by breadth and depth to get
quantities.

CENTER LINE METHOD
This method is suitable for walls of similar cross
sections. Here the total center line length is
multiplied by breadth and depth of respective
item to get the total quantity at a time.
When cross walls or partitions or verandah
walls join with main all, the center line length
gets reduced by half of breadth for each
junction. Such junction or joints are studied
carefully while calculating total center line
length. The estimates prepared by this method
are most accurate and quick.

UNITS OF MEASUREMENTS
The units of measurements are mainly categorized for their nature,
shape and size and for making payments to the contractor and also. The
principle of units of measurements normally consists the following:
• Single units work like doors, windows, trusses etc., is expressed in
numbers.
• Works consists linear measurements involve length like cornice,
fencing, hand rail, bands of specified width etc., are expressed in
running meters (RM).
• Works consists areal surface measurements involve area like
plastering, white washing, partitions of specified thickness etc., and
are expressed in square meters (m2).
• Works consists cubical contents which involve volume like earth
work, cement concrete, Masonry etc are expressed in Cubic meters.

RULES FOR MEASUREMENT
1. Measurement shall be made for finished
item of work and description of each item
shall include materials, transport, labor,
fabrication tools and plant and all types of
overheads for finishing the work in
required shape, size and specification.
2. In booking, the order shall be in sequence
of length, breadth and height
or thickness

3. All works shall be measured subject to the following
tolerances.
• linear measurement shall be measured to the nearest
0.01m.
• Areas shall be measured to the nearest 0.01 sq. m.
• Cubic contents shall be worked-out to the nearest
0.01 cum.
4. Same type of work under different conditions and
nature shall be measured separately under separate
items.
5. The bill of quantities shall fully describe the materials,
proportions, workmanships and accurately represent
the work to be executed.

Generally all the Civil Engineering
projects like roads, railways, earth
dams , canals, buildings etc
involves under earth work. This
work may be either earth
excavation or earth filling or Some
times both will get according to the
desired shape and level.

• The volume of the earth work is
calculated from length, breadth and
depth of excavation of filling.
• Earth work in filling is called as
“earth work in embankment” and
earth work in excavation as “earth
work in cutting”.

LEAD : It is the average horizontal
distance between the center of the
excavation to the center of the
deposition.
LIFT : It is the average height
through which the earth has to be
lifted from source to the place of
spreading.

• Normally earthwork is
estimated for 30 meter lead
for distance and 1.5 meter lift
for height or depth and this
distance of 30 meter and the
height of 30 meter are known
as normal lead and lift .

Calculation of Quantity of Earthwork
The quantity of earthwork may be calculated by
various methods
1. Mid sectional area Method
Volume of Earthwork= Area of Mid section *
distance between sections
2. Mean sectional area Method
Volume of Earthwork= Mean cross sectional area
* Distance between them
3. Trapezoidal Rule
Volume of Earthwork=
L(A1/2 + A2 +A3 + ……+A(n-1) + A(n)/2)
where L= length of equal intervals between section ,
A1,A2,A3 ….. A(n) = area of cross sections along the longitudinal sections

4. Prismoidal Formula
Volume of Earthwork =
L/3(A1+A(n))+4(A2+A4+…+A(n-1))+
2(A3+A5+….A(n-2))
where L = length between the sections
A1= Area of cross section at one end
A(n)= Area of cross section at the
other end
A2,A3,A4= Areas of cross sections of
intermediate sections.

QUANTITY OF STEEL IN R.C.C.
ELEMENTS
• Reinforced cement concrete work is usually estimated
under two items. the concrete work including centering
and shuttering and binding of steel bar in position is taken
under one items under one items in cu m(cu ft.)
• the quantity of steel being small no deduction is made for
steel from the volume of concrete. Binding wire is not taken
separately but include in item of RCC work.
• Centering and shuttering may also be taken under a
separate item is sq. m(sq. ft.).Bending and binding of steel
may also be taken separately in quintal (cwt.).

• Steel reinforcement is calculated as per
actual requirement as laid in position
including overlaps, hooks, cranks etc. and is
determined from the detail drawings.
• If the detailed drawings are not available the
steel reinforcement may be calculated
approximately on the percentage basic of
concrete . The density of steel may be taken
as 78.5 quintal per cu m or 7.85 grams per cu
m.

• The percentage of steel reinforcement
depends on the design of structure . In
absence od detailed design the percentage
for steel concrete may be taken
approximately as given below:-
a) lintel , slabs etc. ...... 0.7 to 1%
b) beams ...... 1 to 2%
c) columns ...... 1 to 5%
d) foundation ...... 0.5 to 0.8%
• For small span and light load less steel is
required and for bigger span and heavier
load greater amount of steel is required.

• In RCC work the end or side covers for steel bar
may be taken as 40 mm to 50 mm(1.5" to 2") and the
bottom and top covers may be taken as 12 mm to 20
mm(0.5" to 0.75") for slab and 25 mm to 50 mm(1" to
2") for beams.
• The length of one hook may be taken as 9 dia. of
bar and the total length of straight bar hooked at
both ends may be taken as L+18 dia.

• For 45° cranked or bent up bar the additional length for one
bent up is equal difference in length of hypotenuse and
base
=d/sin45°-d
=d(1/0.707-1)
=d(1.42-1)
=0.42d
where 'd' is the vertical distance between the center of
upper and lower arms of bent up bars
= Total length of beam or slab minus of top and
bottom cover minus dia of bar.

• For 30° cranked or bent up bar inclined length
of crank
=d/sin30°
=2d
horizontal length of crank=d/tan30°
=1.73d

Schedule of bars
• The schedule of bars is list of reinforcement
bars in a tabular form giving the particulars of
bars, shape of bending with sketches, length of
each, total length and total weight.
• For each type of RCC work a schedule of bars
is usually prepared.
• From the schedule of bars the requirement of
different sizes and lengths of bars may be
known , and may be arranged and bent-up
during the time of construction.

The determination of rate per unit of a
particular item of the work, cost of the
quantity of material, the cost of labours
and miscellaneous petty expanses
require for its compilation is known as
Analysis of rates .

• The reasonable profit usually 10% for the
contractor is also included in analysis of rate.
• Rate of the material are usually taken as the
rate delivered at the site of the work and
include the cost at origin , cost of transport
and taxes.
• If the material are to be carried from a
distant place more than 8 km then cost of
the transport is also added.
• Rate of the material and the labour vary
from place to place and therefor, the rate of
the different items of the work also vary
from place to place.

Purpose of Analysis of Rate
• The quantities of material required
and their cost should be known.
• The number of different categories of
labours required.
• The capacity of doing work per
labours and their wages per day
should be known.

Factor depends the rate of a particular item of
work
• Specification of work and materials, quantity of a
material, proportion of mortor method of
constructional operation.
• Quantities of materials and their number of
different type of labours and their rates.
• Location of the site of work and its distance from
the source of material and the rate of transport
and availability of water.
• Profit and miscellaneous and overhead expanses
of the contractor.

Standard Data Book
It is a book in which the quantity of a material
and labour required per unit of various finished
items of work has been standardized.
Standard Schedule of Rate
It is a book in which the rates of all the material
at source, the wages of the labour, conveyance
charge of material where fixed by the competent
engineering authority for each year for various
government department.

Rates of Materials
• 1st class bricks = Rs 4500 per 1000 Nos.
• 2nd class bricks = Rs 4000 per 1000 Nos.
• Brick Ballast = Rs 800 per cum
• Coarse sand = Rs 800 per cum
• Cement 50 kg bag = Rs 350 per bag
• Twisted bars = Rs 5000 per Quintal
• Bitumen = Rs 10 per kg

Rates of Labours
• Mason = Rs 450 per day
• Plaster = Rs 400 per day
• Carpenter = Rs 400 per day
• Bhishti = Rs 250 per day
• Mazdoor = Rs 250 per day
• Painter = Rs 300 per day

Labour required for different work
• Earth work in excavation: Mazdoor = 33
(% cum) Mason = 1.5
• Earth work in Filling : Mazdoor = 18
(% cum) Mason = 0.5
• Cement concrete : Mazdoor = 15
in foundation Mason =1.5
Bhishti = 2

• Plastering work ( 100 sqm) : Mazdoor = 10
Mason = 10
Bhishti = 2
• Distempering/painting/
white washing ( 100 sqm) : Mazdoor = 5
Painter = 4
• RCC (10 cum) : Mazdoor = 40
Mason = 2.5
Bhishti = 5
Blacksmith = 4
Carpenter = 4

Estimating serves a number of purposes in the
construction process including preparation of
bids and cost control. The role of the estimator
includes preparing conceptual estimates,
preliminary estimates, pre-bid estimates, post
bid estimates, cost control, final project cost,
cost on the operating construction period.
As the works gets organized, smaller
contractors can work on the project at lesser
rate.

Quantity Surveying/longwall shortwall method/Earthwork- Civil Engineering

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