There are separate methods of estimate in civil engineering for Differents works. Some of the civil works are measured in area, some of them are measured in volume and some of them are measured per unit. All of the civil engineering projects can not be estimated with the same process. Some of the works and their methods of estimations are described below.
Methods of estimate in civil engineering
Earthwork shall be taken in cubic m ie. m’ and length breadth and height and depth shall be measured to get cubic content Excavation shall include throwing of excavated earth at least one meter clear of the edge of the excavation.
Dressing or trimming and leveling or grading, ramming, and consolidation thickness of each layer shall be described and included in the item of earthwork. No separate measurement shall be taken, for setting out works, profiles, site clearance, etc. These are included in the rate.
Concrete work shall be measured in cubic m.i.e. m’ or cubic ft. No deduction shall be made for opening up to 0.1 sq.m (1 sq. ft) Formwork, (centering and shuttering). shall be taken under the separate item in sq. m (sq: ft) unless otherwise included in concrete work.
RCC work shall be taken in Cu m’ (Cu ft) excluding steel and the steel reinforcement shall be measured under the separate item in quintal (kg). Normally, centering and shuttering (formwork) shall not be measured separately but be included in the rate of RCC work.
Damp Proof Course
Dam proof course may be measured in sq.m (sq. ft) stating thickness. The horizontal and vertical damp proof course was measured separately.
Brickwork shall be taken in cubic m or (cubic ft). The description of the bricks and of the materials of mortar with proportion should be stated. Different kinds and classes of brickwork shall be taken under separate items. No deduction shall be made for opening up to 0.1 sq m or 1 sq ft.
The stone masonry work shall be taken in cubic m or cu ft. The description of stone materials or mortar and their proportion and nature and type of walling shall be stated. Different types of stone masonry such as Random, ashlar shall be taken under separate items.
Woodwork shall be taken in cubic m or cubic ft. Different kinds of wood and different nature of woodwork shall be taken under the separate items and shall be fully described stating the wood and woodwork.
Door and window shutter shall be taken in sq.m. or sq. ft. Stating ES, the thickness and the kind of wood, and both faces shall be described. Measurement shall be taken from inside after closing the shutters excluding chaukhat.
Door and window chaukhat shall be taken in cubic m or cu ft. Type t. of wood shall be stated and chaukhat of different kinds of wood shall er be kept separately.
Steel and Iron Work
The steel and ironwork shall be measured in quintal or kg. Various items shall be measured under separate items. Bending shall not be measured separately, this shall be included in the item of correspondence.
Roof covering shall be taken in sq m or sq ft. Measurement of the laid roof shall be taken without considering the lap of one over the other. Opening up to 0.4 sq. m (sq ft) shall not be considered. Supporting structure of roof shall be taken under separate item.
The ceiling shall be taken in sq m or sq ft and the method of fixing shall be described. No deduction shall be made opening up to 0.4 sq m or 4 sq ft.
Flooring shall be taken in sq m or sq ft. Net area covered shall be measured stating the thickness, kind of materials, size, mortar, and its mix. Skirting up to 30 cm in height shall be measured in running meter or ft and skirting exceeding 30 cm shall be measured in sq m (sq ft) stating the type of finish.
Plastering and Pointing
Plastering and pointing shall be taken in sq m or są ft stating thickness, mortar, and its mix. Plastering of all roofs ceilings, walls, etc shall be measured under separate items. No deduction shall be done up to 0.5 sq m or 5 sq. ft.
Painting shall be taken in sq m (sq ft) stating the number of coats. Different types of surfaces such as steel, wood, concrete, etc. shall be taken under separate items.
Sanitary and Water Supply Work
All pipes work shall be measured in running meter or ft. Fittings such as bend, junctions, etc. shall not be measured separately the length shall be measured along the center line of the pipe and fittings with stating method of laying.
Electrical wiring shall be taken in points as the light points. fan point etc. Point wiring shall include all necessary work required in complete wiring circuit wiring from main board to submain board shall be measured separately in running meter or ft.
Road metal, ballast, grit, etc shall be measured in cubic m or cu ft. In boulder deduct 10% for voids. The soling coat shall be taken in sq m or sq ft
Bricks and tiles shall be taken in numbers stating size, quality, and class Sand, Surki, stone, ballast, etc. shall be taken in cubic m or cu ft. Cement shall be measured by weight in a 50 kg bag.
Hence, these are the methods of estimate in civil engineering works. Now let us see, Methods of Taking Out Estimates of the buildings.
Methods of Taking Out Estimates
The calculations of quantities of materials can be done using various methods of estimates. The application of an individual method depends upon the design and shape of the building. The different methods are as under:
- Center Line method
- Crossing method
- Out to out and in to in method
- Bay method
1) Center line Method
This method is suitable only if the offsets are symmetrical and the building is more or less rectangular in shape. The centerline of the building is determined carefully after doing deductions for repeated measurements.
This centerline acts as length for the complete calculations of the estimate. If the deduction has not cared for the results of estimates may be wrong. All the walls should have the same section.
2) Crossing Method
In this method, lengths and breadths of the masonry walls at the plinth level are taken (internal dimension of the room + thickness of the walls) for calculating quantities.
The symmetrical offsets’ are a must as in the case of centerline method. The center line length is obtained by calculating the overall perimeter of the building and subtracting the four times thickness of the wall on it. From figure (a) Total length = 2 x 2.6 + 2 x 4.6 – 4 x 0.3 = 13.20 m
3) long wall & short wall Method
In this method, the wall along the length of the room is considered to be a long wall while the wall perpendicular to a long wall is said to be a short wall. To get the length of the longwall or short wall, calculate first the centerline lengths of individual walls
. Then the length of the longwall, (out to out) may be calculated after adding half breadth at each end to its centerline length. Thus the length of the short wall is measured into in and may be found by deducting half breadth from its center line length at each end.
The length of longwall usually decreases from earthwork to brickwork in superstructure while the short wall increases. These lengths are multiplied by breadth and depth to get quantities. This method is most practicable under all circumstances and is generally followed in the P.W.D. for computing the quantities of various items.
4) Bay Method
This method is useful and is generally followed in the case of buildings having several bays. The cost of the one classroom is worked out and then multiplied by the number of bays in that building. The extra cost of the end walls and the difference in framing. If there is any, should be made, so as to arrive at the correct cost.
I hope this article on the “Methods of estimate in civil engineering” remains helpful for you.
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