The document outlines the steps and procedures for conducting surveys for construction projects. It discusses surveying existing site conditions, staking out reference points to guide construction, verifying locations during construction, and conducting an as-built survey once construction is complete. It also mentions coordinating systems used for construction surveys including geodetic coordinates, chainage, building grids, and localized grids.

1. •Survey existing conditions of the future work site including:
i. Topography
ii. EExisting buildings and
iii. Infrastructure
iv. underground infrastructure
whenever possible (for example, measuring invert elevation
diameters of sewers at manholes)
•Stake out lot corners, stake limit of work and stake location of
construction trailer (clear of all excavation and construction)
•Stake out reference points and markers that will guide the
construction of new structures
•Verify the location of structures during construction
•Provide horizontal control on multiple floors
•Conduct an As-Built survey:
“a survey conducted at the end of the construction project to verify
that the work authorized was completed to the specifications set on
plans.”

2. Coordinate systems used in
construction
 Land surveys and surveys of existing conditions are
generally performed according to geodesic coordinates.
However for the purposes of construction a more suitable
coordinate system will often be used.
 Geodetic coordinates:
 In geodetic coordinates, the Earth's surface is approximated
by an ellipsoid, and locations near the surface are described
in terms of latitude(ɸ),Lognitude(λ) and height(h)
 Geodetic latitude is determined by the angle between
the equatorial plane and normal to the ellipsoid, whereas
geocentric latitude is determined by the angle between the
equatorial plane and line joining the point to the centre of
the ellipsoid

3. Chainage or station
 In the case of roads or other linear infrastructure, a chainage (derived
from Gunter's Chain - 1 chain is equal to 66 feet or 100 links) will be
established, often to correspond with the centre line of the road or
pipeline. During construction, structures would then be located in
terms of chainage, offset and elevation. Offset is said to be "left" or
"right" relative to someone standing on the chainage line who is
looking in the direction of increasing chainage.
 Building grids:
In the case of buildings, an arbitrary system of grids is often
established so as to correspond to the rows of columns and the major
load-bearing walls of the building. The grids may be identified
alphabetically in one direction, and numerically in the other direction
(as in a road map). The grids are usually but not necessarily
perpendicular, and are often but not necessarily evenly spaced.

4. Coordinates system:
 Other coordinate systems
In other types of construction projects, arbitrary "plan
north" reference lines may be established, using
Cartesian coordinates that may or may not necessarily
correspond to true coordinates. The technique is
called localized grid. This method uses the plan
building grids as their own ordinates.

5. Equipment and techniques used in construction
surveying
Theodolites:
 are used for accurate measurement of angular deviation, horizontal,
vertical and slope distances.
 With computerisation, electronic distance measurement (EDM), total
stations, GPS surveying and laser scanning have supplemented (and to
a large extent supplanted) the traditional optical instruments.
 Techniques:
 The builder's level measures neither horizontal nor vertical angles. It
simply combines a spirit level and telescope to allow the user to visually
establish a line of sight along a level plane. When used together with a
graduated staff it can be used to transfer elevations from one location
to another. An alternative method to transfer elevation is to use water
in a transparent hose as the level of the water in the hose at opposite
ends will be at the same elevation. A double right angle prism verifies
grid patterns, isolating layout errors

6. Building construction survey:

7. Procedure of building contruction survey:
 Design points from a plot plan are "staked out" onto
the actual property to indicate the location of the
building
 Generally flagged or painted lathe, stakes, or rebar are
used
 Excavation crews use the stakes as markers to dig the
hole where the foundation will be built
 Concrete crews use the offset rebars to set up the
concrete forms into which the foundation will be
poured

8. Uses of building contruction survey
 A construction survey is used to establish or mark the
desired position of building corners, roads, sidewalks,
or utilities, that the engineer has designed.
 A detailed inspection of a property’s condition.
 To move all measurments on the ground the help of
layout.
 To get final positions for work.

9. Instruments used for building
construction survey:
 An auto level or a dumpy level is also a type of surveying
equipment used for measuring horizontal levels. It consists
of a telescope like device fitted on a tripod stand. Auto
level, tilting level, and self-leveling level are all types of
leveling instruments, each providing different rotating
capabilities.
 Global positioning system: GPS has not only made
surveying faster but has increased the accuracy to amazing
heights. GPS works with the help of satellite systems which
provide accurate data directly on the computer screen.
Some GPS equipment even have night vision which
facilitates surveying during the night time. However, it is
said that though GPS helps in acquiring the exact position
of the land

10. Total station:
 Is a theodolite with an Electronic Distance
Measurement Device.EDMD shifted the surveying
technology from optical mechanical devices to digital
electronic devices. In spite of just being distance
measuring equipment, total station can also be used
for leveling when adjusted in a horizontal plane. Most
of the ultra-modern surveying devices are a
combination of one or more of these devices.

11. Tapes
 In building construction survey the most common
instrument used for the measurment is the tapes
 Tapes are of differents materials used for different
purposes.
 These are of different lengths.

12. Road construction survey:

13. Steps for road constructio survey:
 here are just some of the responsibilities of surveyors
when it comes to highway construction surveys
 Determine topography
 Account for infrastructural needs
 Outline best routes
 Physical conditions

14. Railway construction survey:

15. Steps for railway construction
survey:
 Validation of new railway construction
 Marking of tentative alignment.
 Reconnaissance survey.
 Selection of good alignment.
 Preliminary survey of allignment.
 Final survey report.

16. Dams construction survey:

17. Steps for dams construction
survey:
 Examine the water availability.
 Examine the topography.
 Selection of the site.
 River guaging.
 Reconnaissance survey.
 Preliminary survey.
 Final location of survey.
 Final survey report.