To prepare an approximate
estimate Reconnaissance survey a narrow strip of all the possible routes
between selected termini is conducted to determine the best possible routes and
the approximate cost of the projected line.
The following information are
collected from reconnaissance survey –
a. Extent
of waterway for nallah and river crossings.
b. High
flood level (H.F.L.) to determine the height of the road embankment.
c. Number
and length of more important bridges.
d. Total
length of the alignment.
e. Probable
amount of earthwork.
f. Geological
characteristics of the areas to determine foundations of bridges and stability
of embankment.
g. Value
of land.
In order to arrive at a fairly
close estimate preliminary survey along a route or routes selected as a result
of reconnaissance survey is conducted to determine the various distances,
heights and angles.
From the above survey reports,
maps and data preliminary estimates are prepared per km basis by adding the
following heads.
- Earth work estimate which includes provision of borrowed and hauling earth. Approximate estimate may be prepared with the help of contour map.
- Cost of road structures includes cost of bridges and culverts. The spans of the structures are determined and an approximate estimate is found by multiplying the span by cost per meter span of the respective structures of items numbers.
- Cost of sub-base, consisting of soling and edging according to the nature of the soil is selected and worked out for road width per km.
- Cost of base course including premix carpet is estimated from the cost per km basis.
- Cost of boundary pillars Rs.100 L.S. per km.
- Contingency 15 % and W.C. 5 % is added to the total cost from heads (a) to (e).
- Cost of permanent land is finally added to find out the approximate total estimated cost of the project.
