Chapter 2 Approximate Estimates.pptx

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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