major district road, state highway road, national
highway roads, major bridges and flyovers are
being constructed for easy flow traffic. The
flyover or over bridges are to be designed Class
A loading and AA loading.
Necessity of flyover or over bridges:
For easy traffic flow of agricultural
goods and industrial goods without traffic
congestion flyover or over bridges is essentially
to overcome the traffic congestion required.
Traffic censes:
For designing any bridges or flyover the
traffic censes is essential to ascertain the traffic
censes we have to observe the vehicles censes.
Selection of site:
1) The following points are the guiding
factors for selection of suitable site,
2) The roads are crossing
perpendicular to each other.
3) The site should have more traffic
congestion.
4) The availability of men and
materials are to be ascertained
Selection of types of flyover:
We have to select types of flyover
according to traffic censes
Land acquisition:
If the highways or government
promboke land are not available at site the
private land to be acquired for construction of
our bridges.
Benefit cost ratio:
The annual cost of above ratio is
calculated by taking 10% of interest at 1% of
depreciation on the incurred expenditure of the
project and administrative expenses of the
project. Now the ratio between the cost networks
overcomes of indirect income such that road tax
is to be calculated for reasonable periods. For
any project these ratio should be 1:1
Estimate:
The cost of the project includes
expenditure on various items from planning to
the yearly maintenance up to the end of useful
life of the project. Generally they are,
1) Cost of preliminary survey
2) Cost of acquisition of land
3) Cost of various structure
4) Maintenance cost
5) Operation cost
6) Cost of tools and plants
7) Cost of establishment of construction.
Location:
Construction of a flyover across salemKrishnagiri
road in Salem town. The length of
flyover 40m and length of approaches is 600m.
The total length of flyover is 640m and width of
8m.
The component of the project:
This project is consist of main deck slab,
deck beam, piers, girders, foundation, handrails,
wings of slope is 1 in 30. Soil available is clay
mixed with gravel. The bearing capacity of soil
is 245 kN/m². The width of road is 8m, length of
deck is 40m, c/c of pier is 20m, cross beam as
also being placed at 4m c/c. The dia of pier is
1.2m.
Design and drawings:
By adopting the AA loading and being
capability of soil the foundation as been
designed. The piers, wings, decks slab, main
beams and crossbeams are designed suitably.
II.TRAFFIC SURVEY
Traffic survey was made on 06.01.2015, in
the project site from 6.00 pm to7.00 pm. This
time was selected on the basic of the past traffic
study as an average of peak hour. All the four
arms of the site was observed and the number of
vehicles passed was converted to PCU’s
(Passenger car unit).
TRAFFIC PROJECTION:
The passenger car unit of a vehicle type
has been found to be depends up on the size, and
speed of the vehicle type and environment. They
are not dependent on the flow and road width