This document discusses different methods for preparing approximate estimates for civil engineering projects. It describes the purpose of approximate estimates as providing a rough idea of probable project costs for feasibility analysis, administrative approval, and valuation purposes. It then outlines five common methods for approximate cost estimation: service unit method, plinth area rate method, cubical content method, typical bay method, and approximate quantity method. For each method, it provides a brief explanation of how costs are calculated based on units like service units, built-up area, volume, number of bays, or length. The approximate estimate gives initial guidance on project costs before undertaking more detailed planning and estimates.

1. C.S. INSTITUTE OF TECHNOLOGY DEORI DIST.
GONDIA
DEPARTMENT OF CIVIL ENGINEERING
Presented by
Mr.Rikesh S.Bisen

2. Chapter 2 Approximate Estimates

3. Approximate estimate
 Approximate estimate is prepared to decide the financial aspect,
administrative approval for sending the proposal and appraisal of
various civil engineering works
 The approximate estimate is prepared from the practical knowledge
and cost of similar works. The estimate is accompanied by a report
duly explaining necessity and utility of the project and with a site or
layout plan.

4.  PURPOSE OF APPEOXIMATE ESTIMATE
To give a rough idea of the probable expenditure: At the early stages
of the development of a project it is necessary to ensure whether the
project can be financed. A rough idea of the probable expenditure has
to be obtained and if this appears feasible, then further details may
be considered.
Administrative approval: In the case of government and other public
works, proper sanction has to be obtained for allocating the
expenditure required for the detailed investigations and preparation
of plans and estimates. This sanction is given based on approximate
cost estimating method.

5. Valuation and rent fixation:
Sometimes it is required to estimate the cost of an existing
structure, for one or more of the following reasons: for sale or
purchase, for rent fixing, for framing tax schedules, or for
insurance requirement. In these cases the approximate methods
are adopted

6.  Types of Approximate Estimate
1.Service unit method
2.Plinth area rate method
3. Cubical content method
4.Typical bay method
5.Approximate quantity method

7. Service unit method
Buildings are constructed to serve a specific purpose. For example
hospitals are designed to accommodate certain number of beds.
Each bed is then considered a service unit. Hotels are designed to
accommodate certain number of guest rooms. each guest room is
considered a service unit. Same applies to offices, residential
houses,.. etc.
Whenever a building is constructed the Engineer or the architect
keeps the record of the place, actual cost, number of service
units, and the year of construction. From this record, it is
possible to work out the cost per service unit.
Approximate Estimate can be calculated by multiplying no. of
service unit and Rate of per service unit.

8. Plinth area rate method
In this method The built up area of the proposed structure is
worked out, and then multiplied by a suitable rate.
This rate of construction per square meter of built up area is
worked out by dividing the known cost of construction of a similar
building by the built up of that building.
App. Estimate = Built up area of proposed structure X Rate per
Sq. m of built up area

9. • Cubical content method
This method is more accurate than the square meter of floor
area method. because the depth of foundations and the height
of the structure above the ground level are the additional
dimensions taken into consideration.
App. Estimate = volume of buildings x rate/unit volume.
The calculation of Sub structure and super structure is done
separately

10. Typical bay method
 This bay method is applicable in garages, factory, and railway
platform where identical structures are visible.
 Bay in a construction term means a compartment of a building Or
Space between two supports in building. The cost of one bay is
calculated first and it multiplied by the number of bays.
 App. Estimate = No. of Bays X Rate per Bay

11. Approximate quantity method
For estimate of a railway project main work are foundation
embankment in cutting and banking, bridges, culverts, level, and
road crossing, fencing etc. are prepared by knowing the cost per
Km of recently constructed similar structure.
App. Estimate = length of structure in Km X-rate per Km