Construction surveys

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SURVEY 2 (Engr. Fazal-E-Jalal)
Engr. Fazal-E-Jalal
2012
CONSTRUCTION SURVEYS
INTRODUCTION:
SURVEYING TERMS:
Accuracy - The degree of conformity with a standard, or the degree of perfection
attained in a measurement. Accuracy relates to the quality of a result, and is distinguished
from precision, which relates to the quality of the operation by which the result is obtained.
In the fields of science, engineering, industry and statistics, the accuracy of
a measurement system is the degree of closeness of measurements of a quantity to that
quantity's actual (true) value.
The precision of a measurement system, also called reproducibility or repeatability, is the
degree to which repeated measurements under unchanged conditions show the
same results.
Adjusted Position - An adjusted value for the horizontal or vertical position of a survey
station, in which discrepancies due to errors in the observed data are removed. This
adjustment forms a coordinated and correlated system of stations.
Bench Mark –
A relatively permanent object, natural or artificial, bearing a marked
point whose elevation above or below an adopted datum is known.
Usually designated as a BM, such a mark is sometimes further
qualified as a PBM (permanent bench mark), or as a TBM (temporary
bench mark).
Contour Line - An imaginary line on the ground, all points of which are at the same
elevation above or below a specified datum.
Contour Interval - A predetermined difference in elevation (vertical distance) at which
contour lines are drawn. The contour interval is usually the same for maps of the same scale.
Contour Map - A map that portrays relief by means of contour lines.

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2012
Control - A system of points whose relative positions have been determined from survey
data. See:
basic control, horizontal control, vertical control, and picture point.
Control Point - A point whose position (horizontal or vertical) has been determined from
survey data, and is used as a base for a dependent survey.
Control Station - A station whose position (horizontal or vertical) has been determined
from survey data, and is used as a base for a dependent survey.
Control Survey - A survey which provides positions (horizontal or vertical) of points to which
Supplementary surveys are adjusted.
Coordinates - Linear or angular quantities, or both, which designate the position of a point
in relation to a given reference frame.
Correlate - To remove discrepancies that may exist among survey data, so that all parts
are interrelated without apparent error. The terms coordinate and correlate are usually
applied to the harmonizing of surveys of adjacent areas or of different surveys to cover the
same area. Two or more such surveys are coordinated when they are computed on the
same datum; they are correlated when they are mutually adjusted.
Datum - A reference element such as a line or plane, in reference to which the positions of
other elements are determined. See: Horizontal Datum, Level Datum, and Vertical Datum.
Discrepancy - (1) The difference between duplicate or comparable measures of a
quantity. (2) The difference between computed values of a quantity obtained by different
processes in the same survey.
DTM, Digital Terrain Model - A representation in graphic form, on the computer, of the
terrain through the area being surveyed.
Easting - One of the two values indicating the position of a point on a grid system. The
easting Coordinate is abbreviated: E.
Feature Codes - The abbreviation used to define an object collected during a radial
survey.
Fixed Elevation - An elevation obtained, either as a result of tide observations or previous
adjustment of leveling, which is held at its accepted value in any subsequent adjustment.

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2012
Fixed Position - An adjusted value of the position of a point on the earth. The positions
obtained by the adjustment are called adjusted positions, and when used as control for
other survey work they are called fixed positions.
Grid - A network composed of two sets of equidistant parallel lines intersecting at right
angles.
Grid Azimuth - An azimuth measured from grid north.
Grid Coordinates - The numbers of a coordinate system that designate a point on a grid.
Grid Declination - The angular difference in direction between grid north and true north
at any given place.
Grid Distance - The straight line distance between two points, obtained by computations
from their grid coordinates.
Grid Position - The grid coordinates of a point.
Ground Control - In photo mapping, control obtained from surveys as distinguished from
control obtained by photogrammetric methods.
Guard Stake- A stake driven near a point usually sloped with the top of the guard stake
over the point. The guard stake protects, and its markings identify the point.
Horizontal Control - Control stations whose grid coordinates are known.
Horizontal Datum - In plane surveying, the grid system of reference used for the horizontal
control of an area; defined by the easting and northing of one station in the area, and the
azimuth from this selected station to an adjacent station.
Horizontal Position - The grid position of a horizontal control point.
Hub - A wooden stake set in the ground, with a tack or other marker to indicate the exact
position. A guard stake protects and identifies the hub.
Latitude - (1) The angular distance north or south of the equator. (2) In plane surveying, the
amount that one end of a line is north or south of the other end. As the plane coordinates of
a point are known as the easting and northing of the point, the latitude is the difference
between the northings of the two ends of the line, which may be either plus or minus. See:
Departure.

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Engr. Fazal-E-Jalal
2012
Level Datum - A level surface to which elevations are referred. The generally adopted
level datum for leveling in the United States is mean sea level. For local surveys, an arbitrary
level datum is often adopted and defined in terms of an assumed elevation for some
physical mark (benchmark).
Level Net - Lines of spirit leveling connected together to form a system of loops or circuits
extending over an area. Also called a vertical control net.
Mean Sea-Level - The average height of the sea for all stages of the tide. Mean sea level
at numerous tide-gauging stations usually forms the basis of a level datum for large areas.
Meridian - A north-south line from which longitudes (or departures) and azimuths are
reckoned.
Monument - Any object or collection of objects (physical, natural, artificial) that indicates
the position on the ground of a survey station.
Northing - One of the two values indicating the position of a point on a grid system. The
northing coordinate is abbreviated: N.
Occupied Station - A traverse or triangulation station over which a theodolite or an
engineer transit is set up for the measurement of angles at this station. Also, a station at
which angles have been so measured.
Offset Line - A supplementary line close to, and usually parallel to a main survey line to
which it is referenced by measured offsets. When the line for which data is desired is in such
position that it is difficult to measure over it, the required data is obtained by running an
offset line in a convenient location and measuring offset from it to salient points on the other
line.
Order of Accuracy - A mathematical ratio defining the general accuracy of the
measurements made in a survey. The orders of accuracy for surveys are divided into four
classes named: first-order, second-order, third-order, and fourth-order.
Parallax - A change in the position of the image of an object with respect to the telescope
cross hairs when the observer's eye is moved. This can be practically eliminated by careful
focusing.
Permanent Bench Mark - A benchmark of as nearly permanent character as it is
practicable to establish. Usually designated benchmark.

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Engr. Fazal-E-Jalal
2012
Plane Survey - A survey in which the effect of the curvature of the earth is almost entirely
neglected, and computations of the relative positions of the stations are made using the
principles of plane geometry and plane trigonometry.
Position - The place occupied by a point on the surface of the earth. Data that defines the
location of a point with respect to a reference system.
Precision - The degree of refinement in the performance of an operation, or the degree of
perfection in the instruments and methods used when making measurements. Precision
relates to the quality of the operation by which a result is obtained, and is distinguished from
accuracy, which related to the quality of the result.
Prime Meridian - An initial or zero median from which longitudes are reckoned. At an
international conference in 1884, the Greenwich Meridian was adopted by most countries as
the prime meridian for the earth.
Prime Vertical - A vertical circle perpendicular to the plane of the celestial meridian. The
plane of the prime vertical cuts the horizon in the east and west points.
State Plane Coordinate System - A coordinate system that accounts for grid lengths,
sea level factors, and grid azimuths.
Systematic Errors - An error that, as long as conditions are unchanged, will always have
the same magnitude and the same algebraic sign.
Target - Any object to which the instrument is pointed. A target may be a plumb bob or
cord, a nail in the top of a stake, a taping arrow, a range pole, a pencil, or any other object
that will provide a sharply defined, stationary point or line. A target is usually placed
vertically over an unoccupied transit station.
Tie - A survey connection from a point of known position to a point whose position is desired.
Total Station - An electronic theodolite that provides both angle and distance
measurements and displays them automatically.
Transit Station - A mark over which the instrument is, has been, or will be accurately
positioned for use.
Turning Points – Temporary points of know elevation.
Vertical Control - Established benchmarks.

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Engr. Fazal-E-Jalal
2012
=) R.L IS ZERO AT KUNARI, KARACHI (IN PAKISTAN); THOUGH FOR SURE, WE
KNOW THAT THE VALUE IS ZERO AT MEAN SEA LEVEL.
STANDARD ABBREVIATIONS:
CAD Computer Aided
Drafting
CADD Computer Aided Drafting &
Design
CL Center Line DSCON Discontinuity
DTM Digital Terrain Model EDM Electronic Distance Meter
EFB Electronic Field Book HI Height of Instrument
GPS Global Positioning System MRM Mile Reference Marker
NGS National Geodetic
Survey
PC Point of Curvature
PI Point of Intersection
(Survey)
POST Point on Semi-Tangent
POT Point on Tangent PT Point of Tangency
ROW Right of Way SDR Survey Data Recorders
TBM Temporary Bench Mark TP Turning Point
CONSTRUCTION SURVEYING:
It (otherwise known as "lay-out" or "setting-out") is to stake out reference points and markers
that will guide the construction of new structures such as roads or buildings. These markers
are usually staked out according to a suitable coordinate system selected for the project.
HISTORY:
 The nearly perfect squareness and north-south orientation of the Great Pyramid of
Giza, built c. 2700 BC, affirm the Egyptians' command of surveying.
 A recent reassessment of Stonehenge (c.2500 BC) suggests that the monument was
set out by prehistoric surveyors using peg and rope geometry.
 In the sixth century BC geometric based techniques were used to construct the tunnel
of Eupalinos on the island of Samos.

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Engr. Fazal-E-Jalal
2012
Great Pyramid of Giza Stonehenge Tunnel of Eupalinos
ELEMENTS:
Survey existing conditions of the future work site, including topography, existing
buildings and infrastructure, and underground infrastructure whenever possible
(for example, measuring invert elevations and diameters of sewers at manholes);
Stake out reference points and markers that will guide the construction of new
structures;
Verify the location of structures during construction;
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.
HORIZONTAL AND VERTICAL CONTROL:
Control surveys establish a common, consistent network of physical points that are the basis
for controlling the horizontal and vertical positions of transportation improvement projects
and facilities.
Horizontal and vertical control are developed to create a framework around which other
surveys can be adjusted. These control surveys are used for accurate mapping projects in
the construction of underground utility systems, roadways, power lines, tunnels, and many
other high precision projects.
Corridor control surveys ensure that adjacent projects have compatible control. Project
control surveys provide consistent and accurate horizontal and vertical control for all
subsequent project surveys — photogrammetric, mapping, planning, design, construction,
and right of way.
HORIZONTAL CONTROL SURVEYS: Horizontal control surveys coordinate horizontal
positional data. These positions can be referenced by parallels or plane coordinate axes.

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2012
Because they are used as a framework for other surveys, these surveys must be precise and
accurate. These surveys provide a network of monuments or points on the ground that can
be used as the control for any other surveying project, such as a boundary or construction
survey. The advantages of using a horizontal control survey is that lost monuments can be
replaced accurately, surveys can be coordinated, more than one network station can
provide a check to the work, and a reduction in the cost of the project can be achieved.
Most horizontals should (and will) be connected to the control network.
VERTICAL CONTROL SURVEYS: A vertical control survey determines elevation with
respect to sea level. These surveys are also used as a benchmark upon which other surveys
are based and high degree of accuracy is required. These surveys are useful for tidal
boundary surveys, route surveys, construction surveys and topographic surveys. In a vertical
control system, at least two permanent benchmarks should be used, but more may be
required depending upon the needs and complexity of the project. These projects are
needed for the construction of water and sewer systems, highways, bridges, drains, and
other major town or city infrastructure. These surveys can be done alone, but are often done
in conjunction with a horizontal control survey.
***The National Oceanic and Atmospheric Administration (NOAA) maintains the National
Geodetic Survey to which all vertical control surveys should be connected for reference. For
more information about the National Geodetic Survey or the standards for vertical control
surveys, please visit the NOAA website.
BUILDINGS:
INTRODUCTION:
Setting out is the opposite of measurement (which we've considered so far). In setting out,
we transfer design measurements into the field. Normal techniques and instruments are used.
This part describes common techniques for setting out various engineering works in
preparation for construction. If you watch local construction sites, you will see some of these
techniques in action.
After completing this topic you should be able to:
• Understand the principles of setting out
• Know the range of instruments and equipment used
• Choose a method appropriate to the site and type of construction

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Engr. Fazal-E-Jalal
2012
You need to understand horizontal and vertical control points, and the use of sight rails for
projects such as roads, slopes, pipelines and buildings.
• A structure must be correct in all 3 dimensions.
• Setting out must not delay the works.
Principles
We need Horizontal Control Points, and we need points of known elevation - Vertical Control
points. Set out design points from these control points. The control points are established
during the original measurement phase using a theodolite traverse or similar.
CONSIDERATIONS
1. Recording and filing large numbers of field books etc requires some systematic
procedures.
2. Regular inspections and adjustment of instruments are necessary. They should be stored
carefully and protected from site equipment.
3. Design points must be set out from control framework, not from other design points. This
avoids an accumulation of errors.
4. Do site inspections at regular intervals, and check for moved pegs.
5. Checks where possible - independent check of design points from additional control
points
STAGES
First stage
Establish horizontal and vertical control points.
Fix corners of buildings, road centrelines, etc.
Establish site clearance markers (for earthworks operator).
Second stage
Ensure horizontal and vertical control of buildings.
Peg batter slopes for cuttings and embankments etc.

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Engr. Fazal-E-Jalal
2012
PRELIMINARIES
1. Check design. Look for obstacles to setting out.
2. Reconnaissance: Do an on-site check. Decide the location of control points.
3. Traverse points for initial survey can become horizontal control points later.
4. Choose Bench Marks which should be referred to nearby marker or Arbitrary Datum
established.
A survey for engineering design usually produces a contour plan. Works are superimposed on
this initial plan as part of the working drawings, which form part of the contract.
Modifications to the design usually require production of "as-built" drawings from an "as-built"
survey.
HORIZONTAL CONTROL
Setting out is about working from the whole to the part. Secondary points (established from
the primary control points) are used close to the site to enable fast location of design points.
Primary control points should be far enough away from building activity to avoid damage.
Primary control points should be set in concrete. A subsidiary baseline may be established
from primary control points (traverse stations) and used to locate building.
REFERENCE GRIDS
1. Survey grid - usually based on original traverse
- known as eastings and northings
- Control points are original traverse points.
2. Site grid - specified by designer - usually coincides with survey grid.
3. Structural grid may be used to ensure building accuracy (particularly of the verticals)
PRECAUTIONS
1. Instruments must be adjusted
2. Measure horizontal distances, not slopes distances. If you need to set out along the slope,
ADD slope correction.
3. Make checks from other control points

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2012
4. Drive peg into ground at location of design point, and use nail driven into peg to mark the
exact point, where high accuracy is required.
VERTICAL CONTROL
Points of Horizontal control are often used for levels (vertical control) as well. One of these is
usually made the Master Bench Mark, while others become Temporary Bench Marks (TBMs).
TBMs can be established in existing structures, or could be a steel bar set in concrete.
Accuracy must be appropriate to the type of construction. Bench marks should be checked
regularly.
RAILROADS:
Railroads rely heavily on documentation like land surveys for new projects, such as track and signal
installations. Though the railroad may use its own employees for major construction, they often hire outside
land surveyors to eliminate conflict of interest and to shop around for the best deal. As a surveyor, it's your
duty to accurately map the land owned by the railroad and give suggestions to personnel as to the best
locations for new track and signal stations.
Step 1
Use a total station (a device that marries a distance meter
and a theodolite, an angle scope) to determine the
boundaries of land owned by the railroad in that
geographic area, be it just the land along the tracks on a
subdivision or the entirety of the rail yard. Set it up on one
side of the land to be surveyed.
 Step 2

Go to the farthest point of the railroad land or terminal
area with a prism. The total station sends infrared light
toward a stand-alone prism. The light reflects off the prism
to return to the station, which records the distance. The
station reports to a data collector.
 Step 3

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Mark each corner or edge of land using a Global Positioning
System (GPS) receiver, which reports the exact geographic
point to the data collector for storage.
 Step 4
Walk the area, mapping hills, rivers, buildings and landmarks. Include present
railroad track in use and old tracks, noting switch and road grade crossing
location.
 Step 5
Download the data from the collector onto a computer program, like Vector
Expert or Magellan, to calculate the size of land owned by the railroad in that
area, outlining the boundaries.
 Step 6
Write a report, suggesting the best areas to construct new track, including
curves and straights, road grade crossings and signal shacks. Weigh the cost-
effectiveness of installing curves versus straights as to land rights and tangent
land available for purchase.
 Step 7
Give the survey report to the railroad's division engineer, manager of track
maintenance or local road master, who may consult with outside contractors
before installing new track or buildings.
PIPELINES:
Pipeline Condition Survey
Pipeline condition surveys examine the condition and remaining operational lifetime of
pipelines in all types of buildings. Carrying out a survey enables you to anticipate future
repair needs and avoid unexpected leaks, pipe breakages and unnecessary usage
interruptions.
Construction of Pipelines
When a pipeline is built, the construction project not only covers the civil work to lay the
pipeline and build the pump/compressor stations, it also has to cover all the work related to
the installation of the field devices that will support remote operation.

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Engr. Fazal-E-Jalal
2012
The pipeline is routed along what is known as a 'right of way'. Pipelines are generally built
using the following stages:
1. Route (right of way) Selection
2. Surveying the route
3. Clearing the route
4. Trenching - Main Route and Crossings (roads, rail, other pipes, etc.)
5. Installing the pipe
6. Installing valves, intersections, etc.
7. Covering the pipe and trench.
=) Water supply and sanitation in Pakistan is characterized by some achievements and
many challenges. Despite high population growth the country has increased the share
of the population with access to an improved water source from 86% in 1990 to 90% in
2006, and the share with access to improved sanitation from 33% to 58% during the
same period according to the Joint Monitoring Program for Water Supply and
Sanitation.
OTHER CONSTRUCTION SURVEYS:
EQUIPMENT & TECHNIQUES USED IN MINING AND TUNNELING:
Total stations are the primary survey instrument used in mining surveying.
UNDERGROUND MINING:
A total station is used to record the absolute location of the tunnel walls, ceilings (backs),
and floors as the drifts of an underground mine are driven. The recorded data is then
downloaded into a CAD program, and compared to the designed layout of the tunnel.

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Engr. Fazal-E-Jalal
2012
The survey party installs control stations at regular intervals. These are small steel plugs
installed in pairs in holes drilled into walls or the back. For wall stations, two plugs are installed
in opposite walls, forming a line perpendicular to the drift. For back
stations, two plugs are installed in the back, forming a line parallel to
the drift.
A set of plugs can be used to locate the total station set up in a drift or
tunnel by processing measurements to the plugs by intersection
and resection.

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