Methodology for Survey & Setting Out
NAME OF ACTIVITY:
SURVEY AND SETTING OUT
DESCRIPTION OF
AVTIVITY:
Clearing & Grubbing of demarked area & disposal of unsuitable
material with in the specified areas with all lifts and leads complete as
per MORT&H technical Specifications
clause 201 and as per the direction of Employer/NHAI/I.C..
SCOPE OF WORK:
This procedure applies for setting out data of Center line to grades as per contract drawings
for survey of road works undertaken by the company.
MANPOWER REQUIREMENT
Section In-charge
Site In-charge
Section Engineer
Site Supervisor
MACHINERY REQUIREMENT:
Instruments
appropriate for the
intended
setting
out
task and according
to
the accuracy requirements will be used. The instruments will be calibrated periodically as
per our calibration
plan
and
will
be kept
in
good
working condition. The following instruments will be used for setting out survey works.
ORGANIZATIONAL STRUCTURE:
The Sr. Surveyor shall be the Key Personnel, responsible for the Setting out work.
CROSS REFERENCE:
4.1 Contract Documents / Technical Specification.
4.2 MOST Specification, Clause No: 109
DEFINITION:
HIP: Horizontal
Intersection Point
VIP: Vertical Intersection Point
LS: Longitudinal Section.
CS: Cross Section.
SE: Super Elevation.
SETTING OUT:
The Engineering method of transferring the plan & elevation from drawings to the field with a firm control of alignment.
GTS BENCH MARK:
Reference point established by Great Trigonometrical Survey of India development.
These have been set up at interval all over the country with very high precision.
PERMANENT / REFERENCE
BENCH MARK:
Reference point
of known
elevation
established between the GTS
bench
marks
at closer intervals and the contractor shall obtain its value from the Engineer.
BENCH MARK:
It is a fixed reference point of known elevation.
TEMPORORY OR WORKS BENCH
MARK (TBM):
Reference points established from permanent BM at convenient location for setting out the pavement structure.
GRADES:
Elevation of any point with reference to a specified datum.
GRIDLINES:
Imaginary lines running Horizontal & Vertical with each line having a designated northing and easting.
PROCEDURE:
Preparation
4: The working or Temporary Bench Mark (TBM) will be established at every 200 mtr interval and also at or near all drainage
structures and underpasses.
The working benchmark / levels will be approved from the Engineer. Checks will be made on these benchmarks
once every 3months and adjusted if any, got agreed with the Engineer and recorded. An up-to-date record of all TBM including approved adjustment, if any, will be maintained and a copy will be supplied to the Engineer.
Setting Out Works:
1: With reference to the known BM values, the centerline of the proposed road will be located and marked at the existing carriageway, 15mtrs away from the centerline using a total station.
2: All
the HIP’s & VIP’s for Horizontal & vertical curves along the alignment will be located and
pegged
at site
in a similar. As per the coordinates provided by
the
Engineer, the traversing will be closed at BM and error, if any will be linearly distributed.
3: Pegging will be done at toe lines at every 20 mtr longitudinal
intervals of the embankment and in cases of no embankment, 2mtr away from the edge of the proposed road.
4: The alignment
as pegged will
be checked with respect to
the drawing. Upon conformity of
alignment control, Engineer will be required to check and approve the alignment.
Level along & across the alignment:
1: The existing
ground levels
will
be recorded
jointly on a level book along the horizontal sectioning at 10 mtr. Interval for straight as well as curve portions and along the cross sectioning as per the requirements of the Engineer depending upon the profile of the terrains with reference to the known BM elevation.
2: Upon approval of the alignment and existing ground level by the Engineer, road
works will commence for building up pavement layers.
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