nafris surveying

HND/CIVIL/06/46

https://archive.org/stream/surveying00thomuoft#page/114/mode/2upTask 1 (P 1-1, P 1-3,

M1)

A) (P1.1)

Describe the procedure that you are going to follow when producing the survey plan.

What is surveying?

A survey is an activity that collect information in an organized and methodical

how the features of interest of all or part of the units in a well-defined population using

concepts, methods and procedures, and to combine this information into a useful form.

It is defined as the process of measuring horizontal distances, vertical distances and

angles included in determining the location of the points in, on or under the earth's

surface.

The term survey is a representation of surface features in a horizontal plane.

The process of determining the heights on the vertical plane is known as leveling

1Site Surveying Procedures for Construction and the Built Environment

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When the area surveyed is small and the scale to which its result plotted is large, then it is

known as Plan

When the area surveyed is large and the scale to which its result plotted is small, then it is

called as a Map

Setting out of any engineering work like buildings, roads, railway tracks, bridges and

dams involves surveying

Types of Surveying

Plane surveying

Geodetic surveying

Plane surveying

The surveying where the effect of the curvature of Earth is neglected and the surface of

the earth is regarded as plan called surveying.

The accuracy of such surveys is relatively low.

Generally, when the survey is in the area less than 260 square kilometers, that are treated

as plane surveying

Plane surveying is conducted for the purpose of engineering projects

Geodetic surveying

Site Surveying Procedures for Construction and the Built Environment

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The effect of curvature is taken into account.

It is also known as “Trigonometrically Surveying”.

It is a special branch of surveying in which measurements are taken with high precision

instruments.

Calculations are also made with help of spherical trigonometry.

Procedures

1. Land Surveyor must spend time and effort to do a proper research necessary to

determine whether the encroachments, gaps or other irregularities along each line

surveyed. The points can be placed on the line near closed checked and the necessary

points on the basis of these investigations. If these investigations are made. then the

surveyor can not certify to an actual survey of this line and the platform must contain the

appropriate qualifications in accordance with these rules.

2. All visible damage on the property or determined to be located accurately investigate

and form clearly indicated. Regarding recorded, the surveyor must. at least consider the

most recent work and the adjacent flat registered in the subject property and all acts and

flat registered after the date of the act or flat which is based on the investigation.

3. Unless the rule provision, stakes or metal materials should be placed permanently

comparable to all concerned.

4. Where a corner falls just in passing, in a tree in a bouder or stone, etc., a metal or

cuttings are placed on the line so that the hidden point can be accurately located on the

field map. The corners of a property line on a roadside or bounded at points of entry and

exit path. Corners by intermediate benchmarks should not be so, because of its near

points of entry and exit location can be confused with entry and exit points.


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5. The results of a survey when the user informed of the investigation in written or graphic

form, are prepared in a clear and objective manner.

Traverse surveying

Traverse is a method in the field of surveying to establish control networks. It is also used in

geodesy.

Traverse networks involve placing survey stations along a line or path of travel, and then using

the previously surveyed points as a base for observing the next point.

Traverse networks have many advantages, such as:

need for recognition and organizational Less

which may require investigation along a form, the crossing can be altered to any shape

and can accommodate a large number of different areas

Only a few remarks should be taken at each station, while other networks survey a large

number of angular and linear observations to be made and considered

Traverse networks are free from the force of the considerations contained in the

triangular passes systems

Error of scale do not add up as the crossing is made. Oscillation azimuth errors can also

be reduced by increasing the distance between stations.

The movement is more accurate than triangulateration (a combined function of

triangulation and trilateration practice)


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Open traverse and close traverse

A traverse is a series of connected lines whose lengths and directions are known. A closed

traverse is one enclosing a defined area and having a common point for its beginning to end (For

Example a close property boundary). An open traverse is one which does not close on the point

of the beginning (For example: the line center survey of a highway, railroad, etc).

All top graphical surveys should have a skeleton or network of traverses to serve as horizontal

control.

Closed Traverse: Boundry is closed


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Open traverse Boundry is not closed

Checkpoint - The first control / base used for preliminary measures which can consist of any

known point may provide precise control of distance and direction that is, coordinates, elevation,

bearings, etc

Departure - The checkpoint starting the movement.

observation - All checkpoints set known or observed in the traverse.

Terminal - Checkpoint initial end speed coordinates are unknown.


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Control networks

The foundation control array of two or three dimensions is the largest in the topography of large

or small areas of land process.

Control networks include a number of points or positions that are spatially in order to control

points of the investigation or additional control dimensions on the site.

Use according to one of the following methods:

displacement

Networks

Electronic Distance Measurers (EDM)

GPS satellites


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B) (P1.3, M1)

Describe the instruments that you are planning to use, including the electronic

surveying instruments.

What are the electronic surveying instrument using construction site??

Classification of surveying

Chain surveying

Theodolite surveying

Levelling

Total station

Global positioning systems (GPS)

Chain surveying

The different accessories used in chain surveying are :

1. Metre chain

2. Chain pains

3. Measuring tape

4. Ranging rod

Metric chain surveying

The distance between the outside faces of handles of a fully stretched out chain is the

length of the chain.

The length of the chain, like 20m is engraved on the handles.

While measuring the long distance, the chain will have to be used a number of times.

Arrows are driven at the end of every chain length.

For holding the arrows in position, grooves are cut in the outside face of the handles.

The radius of the groove is the same as that the arrows.

For convenient handling of the chain, the handle joint is made flexible so that it is

possible to swivel to handle round the eye bolt.


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Chain pins

Chain pins or arrows are used with the chain for marking each chain length on the ground.

The arrow is driven into the ground at the end of each chain length is measured.

Chain pins the arrow should be made of good quality hardened and tempered steel wire

of minimum tensile strength of 70 kg/mm

The overall length is 400 mm and thickness is 4mm.

The wire should be black enamelled.

The arrow has a circular eye at the one end is pointed at the other end

Measuring tape

There are different types of tapes are used. They are

(a) Cloth or linen type

(b) Metallic Tape

(c) Steel Tap


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Ranging rod

Ranging rods should be straight and free from warps.

The deviation in straightness should not exceed 5mm in a 2 m length.

The ranging rod is painted in red and white in alternate band lengths of 200 mm each.

The bottom end of the rod is fitted with a pointed, hollow, cast iron shoe or steel shoe of

15 cm length.


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Advantages and disadvantages of chain surveying

Advantages:

It is simple

It does not require any costly equipment

It is adopted for preparing plans for small area

Disadvantages:

It cannot be used for large areas

It cannot be used in thick bushy areas with ups and downs.

Chain surveying is not always accurate.

2. Leveling

It is a surveying method used to determine the level of points/objects with reference to the

selected datum.

Leveling of an instrument is done to make the vertical axis of the instrument truly vertical.

Generally, there are three leveling screws and two plate levels are present in a theodolite

instrument. Thus, leveling is being achieved by carrying out the following steps

Step 1: Bring one of the level tube parallel to any two of the foot screws, by rotating the upper

part of the instrument.

Step 2: The bubble is brought to the centre of the level tube by rotating both the foot screws

either inward or outward. The bubble moves in the same direction as the left thumb.

Step 3: The bubble of the other level tube is then brought to the centre of the level tube by

rotating the third foot screw either inward or outward. [In step 1 itself, the other plate level will


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be parallel to the line joining the third foot screw and the centre of the line joining the previous

two foot screws.]

Step 4: Repeat Step 2 and step 3 in the same quadrant till both the bubble remain central.

Step 5: By rotating the upper part of the instrument through 180°, the level tube is brought

parallel to first two foot screws in reverse order. The bubble will remain in the centre if the

instrument is in permanent adjustment.

Otherwise, repeat the whole process starting from step1 to step5.

It is also used to set out engineering works.

Uses of Levelling:

To determine the difference in levels of points/Objects

To obtain contour map of an area

To obtain cross section of roads, canals etc.,

To determine the depth cutting and filling in engineering works.

To establish points or erect machinery or construct a building component at a

predetermined level.

Bench Mark:

It is surveyor’s mark cut on a stone/ rock or any reference point used to indicate a level in a

levelling survey.

Reduced Level:

Reduced level of a point is the level of the point with respect to the level of permanent

feature or bench mark.


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It indicates whether the point is above or below the reference point.

Instruments used in levelling are,

(i)Levelling instrument

(ii)Levelling staff

Levelling Instrument : Simplest form of levelling instrument is dumpy level.

The different parts of levelling instrument are,

(a) Telescope

(b) Eye-piece

(c) focussing knob

(d) level tube

(e) cross bubble

(f) foot screws

(g) levelling head

(h) diaphragm

(i) ray shade


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Theodolite

Main steps of theodolite traversing field work.

a. Measure the Horizontal angles

b. Measure the Vertical angle

c. Measure the distance

Traverse legs are measured by using electronic devices, a 30-meter steel tape, or trig-traverse

procedures. At each traverse station, a horizontal angle is measured and used to determine the

azimuth of the next traverse leg. These measurements are used to compute the relative horizontal

position of each unknown traverse station on some system of coordinates, such as the UTM grid

system. A vertical angle is also measured at each station and is used to determine the height

above or below vertical datum of each of the unknown traverse stations. In FA surveys, the

angular measurements may be made with one of two instruments, depending on the accuracy

required and the echelon at which the traverse is conducted. These instruments are the T16 and

T2 theodolites.

Field work

In a traverse, three stations are considered to be of immediate significance. These stations are

referred to as the rear station, the occupied station, and the forward station. The rear station is

that station from which the persons performing the traverse have just moved or a point to which

the azimuth is known. The occupied station is the station at which the angle-measuring

instrument is set up. The forward station is the next station in succession and is the immediate

destination of the party. During the traverse (Figure 5-2), the horizontal angles, vertical angles,

and distances are measured.


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a. Horizontal Angles. Horizontal angles are determined from instrument readings made at

the occupied station by sighting the instrument on the rear station and turning the instrument

clockwise to the forward station. When measuring horizontal angles, the instrument is always

sighted at the lowest visible point of the station markers designated the rear and forward

stations. Horizontal angles are used in determining azimuths.

b. Vertical Angles. Vertical angles are determined from instrument readings made at the

occupied station to the height of instrument on the station marker (usually a range pole) at the

forward station. When the distance between two successive stations in a traverse exceeds

1,000 meters, the vertical angle must be measured reciprocally (measured from each end of

that particular traverse leg). This reciprocal measurement procedure is used to eliminate

errors caused by curvature and reflection. Vertical angles are used in determining the

difference in height between stations.

c. Distance. The distance between the occupied station and the forward station is measured

by using electronic devices, horizontal taping, or trig-traverse procedures. The distance is

used in conjunction with the horizontal and vertical angles to determine coordinates and

height.


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Temporary adjustment of vernier Theodolite

At each station point, before taking any observation, it is required to carry out some

operations in sequence. The set of operations those are required to be done on an instrument in

order to make it ready for taking observation is known as temporary adjustment. Temporary

adjustment of a vernier theodolite consists of following operations:

Centering,

Leveling and Focussing


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Electromagnetic distance measurement

Applications of Electromagnetic Distance Measurement (EDM) in Civil Engineering

and Mining Engineering, or in both those engineering fields such as,

Calculating areas

Remote heights

Tie distances

Calculating areas

Set up the total station in the terrain so that it is within view of the entire area to be surveyed. It

is not necessary to position the horizontal circle.

Determine the boundary points of the area sequentially in the clockwise direction. You

must always measure a distance.

Afterwards, the area is calculated automatically at the touch of a button and is displayed.

Remote heights

Set up a reflector vertically beneath that point the height of which is to be determined. The total

station itself can be situated anywhere.

Measure the distance to the reflector.

Target the high point.

The height difference H between the ground point and the high point is now calculated at

the touch of a button and is displayed.


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Tie distances

The program determines the distance and height difference between two points.

Set up the total station at any location.

.Measure the distance to each of the two points A and B.

The distance D and the height difference H are displayed at the touch ofa button.

Total station


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A total station combines an electronic transit with an electronic measuring device to measure

distances between the instrument and survey points to calculate spatial coordinates. While it

sounds complicated, with a little practice you'll be setting up and using your total station in no

time.

many modern theodolites, costing up to $10,000 apiece, are equipped with integrated

electro-optical distance measuring devices, generally infrared based, allowing the measurement

in one go of complete three-dimensional vectors — albeit in instrument-defined polar co-

ordinates, which can then be transformed to a pre-existing co-ordinate system in the area by

means of a sufficient number of control points. This technique is called a resection solution or

free station position surveying and is widely used in mapping surveying. The instruments,

"intelligent" theodolites called self-registering tacheometers or "totalstaaions”, perform the

necessary operations, saving data into internal registering units, or into external data storage

devices. Typically, ruggedized laptops or PDAs are used as data collectors for this purpose.

Temporary Adjustment of Total station

Adjustment of level :

Adjustments made at each setting of the instrument before taking observations are known as

temporary adjustments.

Temporary Adjustments : includes

Setting up the level

Levelling up

Elimination of parallax


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1. Setting up the level : This operation includes fixing the instrument on the tripod and also

approximate levelling by leg adjustment.

2. Levelling up : Accurate levelling is done with the help of foot screws and by using plate

levels. The object of levelling up the instrument is to make its vertical axis truly vertical.

3. Elimination of parallax : If the image formed by the objective does not lie in the plane

of the cross hairs, there will be a shift in the image due to shift of the eye. Such displacement of

image is termed as parallax. Parallax is removed in two stages.

Focusing the eye for distinct vision of cross hairs.

Focusing the objective so that image is formed in the plane of cross hairs

To use a total station for setting out, it must be levelled and then centred over a control point in

the same way as for a theodolite. As before this must be done correctly otherwise the subsequent

readings taken with the instrument will not give the correct results.

Having set up the total station, it has to be orientated horizontally to the site coordinate system

and it may also have to be orientated vertically. For horizontal orientation, the coordinates of the

control point at which the instrument is set up are entered into the total station.

An adjacent control point is then chosen as a reference point (reference object) and the

coordinates for this site are also keyed in. To orientate the total station, the RO is sighted and the

horizontal circle orientation programme automatically computes the bearing from the total

station to the RO.

For vertical orientation, the height of collimation of the total station has to be determined. If the

height of the control point at which the total station is known, this is entered into the instrument

or is already stored in the control point data.


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Once the total station has been orientated it can be used for setting out horizontal positions either

using the coordinates of the points to be set out directly or using bearing and distance values

calculated from these coordinates.

Two approaches can be used.

-When the coordinates of the point to be set out are used, these are usually contained in the file

together with the coordinates of the control points for the project, and this is downloaded to the

total station before work commences.

-If the bearing and distance to be set out are known, these can also be used for setting out. They

are entered into the total station and, as soon as the appropriate key(s) are pressed to activate this

is setting out mode, the instrument once again displays the difference between the entered and

measured bearing values.

Task 02


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total angle

= 94°10’00”+ 178°19’00”+ 178°21’45”+ 94°42’25”+ 158°07’30”+ 89°03’55”+ 167°15’50”

= 960°00’25”

Primary angle for seven side picture

= (7-2)×180°

= 900°00’00”

correction

= (960°00’25” – 900°00’00”) ÷ 7

= 8°34’20.7”


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= 08°34’20” & 08°34’21”

angle corrections

<GAB = 94°10’00” - 08°34’20”

= 85°35’40”

<ABC = 178°19’00” - 08°34’20”

= 169°47’24”

<BCD = 178°21’45” - 08°34’21”

= 169°47’24”

<CDE = 94°42’25” - 08°34’21”

= 86°08’04”

<DEF = 158°07’30” - 08°34’21”

= 149°33’09”

<EFG = 89°03’55” - 08°34’21”

= 80°29’34”

<FGA = 167°15’50” - 08°34’21”

= 158°41’29”

WCB of lines

AB =187°22’20”

BC =187°22’20” + 169°47’24” – 180° =177°07’00”

CD =177°07’00” + 169°47’24” - 180° =166°54’24”


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DE =166°54’24” + 086°08’04” - 180° =073°02’28”

EF =073°02’28” + 149°33’09” - 180° =042°35’37”

FG =042°35’37” + 080°29’34” + 180° =303°05’11”

GA =303°05’11” + 158°41’29” - 180° =281°46’40”

AB =281°46’40” + 085°35’40” - 180° =187°22’20”

Line Departure latitude

AB - 103.4 * sin(WCB AB –180°)

= - 13.2678

- 103.4 * cos(WCB AB –180°)

= -102.5452

BC +157.25* sin(180°-WCB BC )

= +7.9101

- 157.25 * cos(180°-WCB BC )

= -157.0509

CD +143.36* sin(180°-WCB CD )

= +32.4765

- 143.36* cos(180°-WCB CD )

= -139.6330

DE +160.08* sin(WCB DE )

= +153.1188

+ 160.08* cos(WCB DE )

= +46.6930

EF +176.74* sin(WCB EF )

= +119.6166

+ 176.74* cos(WCB EF )

= +130.1111

FG - 110.6 * sin(360°-WCB FG )

= -92.6660

+ 110.6 * cos(360°-WCB FG )

= +60.3769

GA - 140.83* cos(WCB GA-270° )

= -137.8651

+ 140.83* sin (WCB GA-270° )

= +28.7457

departure correction

= - 13.2678+7.9101+32.4765+153.1188+119.6166-92.6660-137.8651

= +69.3231

latitude correction


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= -102.5452-157.0509-139.6330+46.6930+130.1111+60.3769+28.7457

= - 133.3024

bowditch error

Departure of AB

(69.3231÷992.26)×103.4

=7.2239

Latitude of AB

(-133.3024÷992.26)× 103.4

= -13.8910

Departure of BC

(69.3231÷992.26)×157.25

=109861

Latitude of BC

(-133.3024÷992.26)× 157.25

= -21.1253

Departure of CD

(69.3231÷992.26)×143.36

=10.0157

Latitude of CD

(-133.3024÷992.26)× 143.36

= -19.2593

Departure of DE

(69.3231÷992.26)×160.08

=11.1838

Latitude of DE

(-133.3024÷992.26)× 160.08


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= -21.5055

Departure of EF

(69.3231÷992.26)×176.74

=12.3477

Latitude of EF

(-133.3024÷992.26)× 176.74

= -23.7436

Departure of FG

(69.3231÷992.26)×110.6

=7.7269

Latitude of FG

(-133.3024÷992.26)× 110.6

= -14.8582

Departure of GA

(69.3231÷992.26)×140.83

=9.8389

Latitude of GA

(-133.3024÷992.26)× 140.83

= -18.9194

bowditch error correction

line departure correction(m) latitude correction(m)

AB - 13.2678 - 7.2239 -102.5452 + 13.8910


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= -20.4917

= -88.6542

BC +7.9101 - 10.9861

=-3.076

-157.0509 + 21.1253

= -135.9256

CD +32.4765 - 10.0157

=+22.4608

-139.6330 + 19.2593

= -120.3737

DE +153.1188 - 11.1838

=+141.935

+46.6930 + 215055

= +68.1985

EF +119.6166 - 12.3477

=+107.2689

+130.1111+ 23.7436

= +153.8547

FG - 92.6660 - 7.7269

=-100.3929

+60.3769 + 14.8582

= +75.2351

GA - 137.8651 - 9.8389

=-147.704

+28.7457 + 18.9194

= +47.6651

Ʃdeparture=0 Ʃlatitude=0

Co ordinates

A

( 1000 , 2000)

B

( 1000 -20.4917 , 2000 -88.6542 )

(979.5083 , 1911.3458)

C

( 979.5083 -3.076 , 1911.3458 -135.925 )

(976.4323 , 1775.4202)


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D

( 976.4323 +22.4608 , 1775.4202-120.3737 )

(998.8931 , 1655.0465)

E

( 998.8931 +141.935 , 1655.0465 +68.1985 )

(1140.8281 , 1723.245)

F

( 1140.8281 +107.2689 , 1723.245 +153.8547 )

(1248.097 , 1877.0997)

G

( 1248.097 -100.3929 , 1877.0997 +75.2351 )

(1147.7041 , 1952.3349)

A

( 1147.7041 -147.7041 , 1952.3349 +47.6651 )

(1000 , 2000)


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Task 3 (P 4-1, P 3-1, P 3-2, P 3-3)

Describe the procedure that you are going to follow for the development of the contours

from the point data available, by graphic interpolation.

What are the users of contours

Contour maps are use ful because they provide valuable information in the field some of these

users are such as:

1. The nature of the terrain and its slope can be estimated.

2. The work of the land can be estimated for civil engineering project such as road

construction

3. You can identify the ideal location for a project of the contour map of the region.

4. he visibility Inter-point can be determined using contour maps.

What are the method of contouring

Two methods of contouring such as:

1. direct method

2. indirect method

Direct method

In the direct method, the points of equal elevation on the ground and are physically drawn on the

map. This is a very tedious process and requires more time and resources than the indirect

method.


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Indirect method

Indirect method of contouring there are three methods:

1. cross section method:

Cross section method is most suitable for preparing contour maps for road works, rail works,

canals etc.

2. squares or grid method:

Squares or grid method is suitable for contouring of plains or gently sloping grounds.

3. Tacheometric method:

Tacheometric method is adopted for contouring of very steep hills

A contour line is an imaginary line points of equal elevation. These lines are drawn on the

plan after the establishment of an area reduces the levels of various parts of the region.

Contours in a different zone are drawn into constant elevation between two consecutive lines.

For example these image shows

outlines of a boundary area of the range of 1 m. In the level of contour lines

Characteristics of Contours


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The contours have the following characteristics

Contour lines must close, not necessarily in the limits of the plan

Widely spaced contour indicates flat surface.

Closely spaced contour indicates steep ground

Irregular contours indicate uneven surface.

If contour lines meet somewhere

If contour lines cross each other


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Task 3 (3.1)

Explain the different applications of the computer software and evaluate the benefits of

computer software to solve the following typical surveying problems.

Computer soft wares

Auto cad civil 2d & 3d

Spread sheets

Math lab

Auto desk

Computer aided design

Auto cad civil 2d & 3d

Auto cad civil 2d & 3d is a engineering software these software using for civil engineers,

designers and engineering draughmans.

These projects fall under the three main categories of land development, water and transportation

projects and can include construction area development, road engineering, river development,

post construction, cannels, dams, embankments and many others.

Types

Auto Cad LT

Auto cad LT is a lower cost version of auto cad , with reduced capabilities , first released

November 1993


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Auto Cad WS

Is a mobile application enabling registered users to view , edit, and share Auto Cad files via

mobile device using a limited auto cad feature set

Student versions

Auto Cad is licensed at a significant discount over commercial retail pricing to qualifying

students and teachers, with a 36 month license available.

Currently people using AutoCAD or AutoCAD on a learning plan inherit many advantages of

using civil 3D. Civil 3D was created to be a complement to AutoCAD, but the popularity and

demand has increased.

Spread sheet

A spreadsheet is a computer program for an interactive application for organizing and analyzing

the data form. Spreadsheets developed and computer simulations worksheets accounting paper.

The program operates on the data represented in the form of matrix organized in cell rows and

columns.

Each cell in the matrix is an element of model-view-controller that can contain numeric and text

data or formula results automatically calculated and displayed based on the content of other cell

sizes.

The user of the spreadsheet can make changes to a stored value and observe the effect on the

calculated values. This makes the sheet useful for calculations because many cases can be

investigated quickly without tedious manual recalculation. Modern spreadsheet software can

have multiple sheets that interact, and can display the data in text and figures, or graphically

calculations such as net present value or the standard deviation can be applied to tabular data

with a pre-programmed into a formula. Spreadsheets also provide conditional expressions,

functions, conversion between text and numbers and functions that operate on strings.


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Math lab

Math lab is a computer algebra system

calculations such as net present value or standard deviation can be applied to tabular data with a

pre-programmed into a formula. Spreadsheets also provide conditional expressions, functions to

convert between text and numbers and functions that operate on strings

C) (P3.2)

Explain the use of information taken from the digital mapping databases and how you can

relate them to your site surveying project.

Digital geological mapping is the process by which the geological, analyzed and recorded in the

field and displayed in real time on a computer or personal digital assistant is observed. The main

function of this emerging technology is to produce georeferenced geological maps that can be

used and updated while conducting fieldwork.

eological mapping is a process of interpretation that involves several types of information from

data analysis to personal observation, all synthesized and recorded by the geologist. Geological

observations traditionally have been recorded on paper or posters of standardized, in a notebook

or on a map.

Geological mapping is a process of interpretation that involves several types of information from

data analysis to personal observation and recorded by the geologist.

Geological observations traditionally have been recorded on paper or posters of standardized, in

a notebook or on a map

Some advantages of digital mapping

The data entered by a geologist may have less error than data transcribed by a clerk data

entry.

Data entry by geologists in the field can take less input total time data back to the office,

potentially reducing the total time required to complete a project.


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The extent of real world objects and their attributes can be entered directly into a

database with the ability to geographic information system (GIS).

The features can be automatically color-coded and symbolized based on established

criteria.

Many maps and images (geophysical maps, satellite images, orthophotos, etc.) can be

easily transported and displayed.

Some disadvantages of digital mapping

Computers and related items (batteries, pencil, camera, etc.) shall be performed in the

field.

The field of data entry on the computer can take more time to physically write on paper,

which can result in more programs on the ground.

The data entered by various geologists can contain several inconsistencies that the data

entered by a person, so that the database more difficult to query.

Written convey to the reader the details through images that can not communicate with

the same data analyzed in size descriptions.

The initial cost of the computer and digital geological support team can be. In addition, hardware

and software must be replaced from time to time due to damage, loss and obsolescence. Mobile

products on the market were discontinued as soon as technology and consumer interests evolve.

A product that works well for digital mapping may not be available for purchase in the following

the test of several brands and generations of hardware and software is prohibitive.


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A) (P3.3)

Evaluate the above statement by considering both positive and negative aspects related to

use of GPS.

The Global Positioning System (GPS) is a satellite navigation system based in space that

provides location and time information in all weather, anywhere on or near the Earth, where

there is a line unobstructed to four or more GPS satellites.

The system provides critical functions to military, civil and commercial users worldwide. It is

maintained by the Government of the United States and is freely available to anyone with a GPS

receiver.

There are software like auto civil and auto plotter clubbed with AutoCad which can be used for

plotting contours at any specified interval and for plotting cross-section along any specified line.

GPS error analysis examines the sources of error in the results of GPS and the expected size of

these errors.

Make corrections to clock errors of the GPS receiver and other effects, but there are still residual

errors are not corrected.

Sources of error signals measures the arrival time, numerical calculations, atmospheric effects is

data and clock signals, multipath, and natural and artificial interference. The importance of

residues from these sources depend on the geometric dilution of precision.

GPS

The signal can be blocked in wooded areas or thick urban areas

The data can be read directly from the GIS databases, making the data entry steps or

conversion of unnecessary intermediate data.


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DGPS is more expensive, requires more time to collect data in the field and more

complex post-processing to obtain more accurate information

sufficient accuracy for census mapping of many applications of high precision achievable

with differential correction

total Station

The field work was carried out very quickly.

Measurement accuracy is high.

involved in reading and recording manual errors are eliminated.

Calculation of coordinates is very fast and accurate. Even adjustments temperature and

pressure are carried out automatically.

Computers can be used for mapping and contour mapping and cross sections. Contour

intervals and scales can be changed quickly.


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Task 04

a) Graph sheet

b)

1. Explain the different methods existing, to measure areas on prepared plans.

Planimeter

A planimeter is an instrument used to measure the surface of a two-dimensional form, usually

one that is too complex for manual measurement. The machines of the apparatus of the method

of calculating the area using a formula known as the Green's theorem. Although a planimeter can

be used in a small physical area itself, it is most commonly used in a wide representation as a

map.

trapezoidal rule

Area is divided into a series of trapezoids If there are "n" number of time slots, there are "n + 1"

number of coordinates Mathematically correct and that all calculations are performed with pure

corner triangle and trapezoidal method direct and involves fewer calculations As difficult as it

involves finding the point of intersection The intervals are of the same value.

Simpson’s rule

Simpson’s rule is a numerical method that approximates the value of a definite integral by using

quadratic polynomials. Simpson's Rule is even more accurate than the Trapezoid Rule


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Produces more accurate results, as instead of connecting 2 adjacent points merely by a straight

line, a parabola is chosen Involves less calculationNot practically usable as it expects the data to

follow the rules below:

Number of intervals must be an even number

A minimum of 3 points are required

Intervals are expected to be equal

2.

Using Simpson’s rule for 0-100m

Area= 13

(width of interval) × (first + last coordinate) +4 ( sum of even ordinate) +2 (sum of odd)

Area = 13

* (20)* (8.4+7.3)+4(9.5+6.23)+2(7.34+7.89)

= 203

*(15.7+62.92+30.46)

= 203

*109.08

= 727.2m2


Chainage along the

survey line (m) 0.0 20.0 40.0 60.0 80.0 100.0

Ordinate (offsets)

(m) 8.4 9.5 7.34 6.23 7.89 7.3

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Using Simpson’s rule for 100-190

= 13

*30* (7.3+4.5)+4(9.81)+2(6.65)

= 10*(11.8+39.24+13.3)

= 10*64.34

= 643.4m2

Total area = 727.2+643.4

= 1370.6m2


Chainage along the survey

line (m) 100.0 130.0 160.0 190.0

Ordinate (offsets)

(m) 7.3 9.81 6.65 4.5

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3.

Grid method

The method of the grid extends over a DAM another excavation depths. Upgrading a volume of

excavation sky Borrow calculated using a grid in the area of excavation. Grids can be staked

square Pará 10, 20, 50, 100 or MAS cakes, depending on the project and do not disrupt the

desired accuracy. For each grid elevations final para Every corner of each square of the grid in

place. Remaining other existing ESTOS elevations in section Description same location to

determine the depth of cut or the filling height at each corner. Average each grid for the UN in

the depths / heights multiplies the Four Corners area of the square by subsection determine the

volume of earthworks Associated With a surface grid. The total volume of earthwork project

itsel f calculated by summing the volumes of each grid in the area of excavation. The volumes

calculated self FOLLOWS:

V = ((D1 + D2 + D3 + D4) / 4) × A × (1/27)

Where V = volume (cubic meters)

A = surface of the grid (square feet)

D = depth of cut / fill in every corner of the grid (pies)

prismatic formula

The prismatic formula (PF) allows a mayor precision ASM. It is particularly useful when the

ground is uneven or irregular Between sections significantly. Zone UN ANADE PF of the cross

section of a supplementary manner between the two half sections which define the volume which


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is calculated. Note that this section is calculated separately and not averaged between two end

zones. The volumes calculated self FOLLOWS:

V × L = ((A1 + (4 x Am) + A2) / 6) x (1/27)

Where V = volume (cubic meters)

A1, A2 = areas adjacent sections (square feet)

Am = area of a half-way cross-section (square feet)

L = distance from section A-Long Base Line (pies)

Contour Area Method

This is a general method that applies to a variety of situations. Using a preliminary grading plan,

separate areas from cut and fill, by dividing the areas between existing and proposed contours

Contour area method formula is

V = i(A1+ A2+ A3+ …….+.An) ÷(27)

Where,

V = volume(yd3)

A = area between each contour(ft2)

i = contour interval(ft)


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Task 5

A)

Selecting the degree of curve

Curves are usually fitted to tangents by choosing a D (degree of curve) that will place the

centerline of the curve on or slightly on or above the grade line. Sometimes D is chosen to

satisfy a limited tangent distance or a desired curve length

Horizontal curves

When a route change horizontal direction causing the point that changes the direction of a point

intersection between two straight lines is not possible. The change of leadership would be too

abrupt for Security Modem, high-speed vehicles. It is therefore necessary to file curve between

the right lines. Straight lines are called a path tangent in that the tangents to the curved lines are

used for change of address.

Type of horizontal curves


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Element of horizontal curve

Procedure of horizontal curve

Address changes to the research carried out by a horizontal curve. Horizontal

curves are tangent to a straight section of the survey, or another curve. The

beginning point of the curve or bend PC. Also, the tangent of the curve is shown,

and the station at the intersection, or PI, is labeled.


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The P.C. and P.T. stations follow the curved path of the survey line. However,

the P.I station is based upon the tangent length the difference between the P.I.

and P.T. stations will not equal to the tangent length.

Data from the horizontal curve is usually on the same page in which the curve

appears, and often referred to in the curve number.

Choosing D when the tangent distance is limited.

The tangent distance must often be limited in setting a curve. Examples are stream crossings,

bluffs, and reverse curves. In the case of stream crossings or bluffs, it is a matter of not starting a

curve until a certain point is reached. In the case of reverse curves, the total tangent distance

between PI's must be shared by two curves and not overlap. Some road standards may call for a

minimum tangent between curves. In any case, where the tangent is limited, D is usually chosen

by using the desired tangent distance.


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Tangent Offsets

In the tangent offset method, distance measured from the PC and PT toward the PI (called TO's

or tangent offsets) are used to set stations on the curve

Chord Offsets

The chord offset method of laying out a simple curve uses only a steel tape or surveyor's chain.

It is a particularly effective way to "try out" a curve in a particular situation to see how it fits.

Even though this method of curve location is mathematically correct, it is best suited to the

location of curves whose lengths are equal to multiples of the chosen chord length. However, if

the PC and PT of the curve are established in the usual way, the technique can be used to set

POC's coming in from the PC and PT with given chord lengths and letting the odd distance fall

in the center of the curve.

B)

What is setting out?

A common definition is that the opposite of surveying. Whereas survey is a method of forming

maps of a particular area or site, outlining plans begins and ends with different elements of a

particular plan correctly positioned on site

The aims of setting out

There are two main aims when taking setting out operation

1) The various elements of the plan must be correct in three dimensions, both relative and

absolute, is each must be the right size in the right position and the plane reduces correct

2) Once in place begins to move quickly with little or no time for that work can take place

and the cost can be minimized. Always remember that the commercial purpose of the

masters is a goal called back to effectively


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Coordinate positioning teachniuqes

for setting out by coordinates to be possible, a control network consisting of coordinated

points (with heights) must be established onsite. These are obtained by using theodolites,

tapes, GPS and total station.

Setting out using a theodolite and tape

To set out using coordinates by theodolite and tape, one of the following

procedures is used:

1. Angle and distance from two control points e.g. from point A below, can be set out from a

control point S using one of two methods:

Using the inverse calculation, determine the horizontal length l (SA) and the whole circle

bearings of ST and SA.

With the theodolite set up at S, sight T and set the horizontal circle to read zero along this

direction. Then the telescope is rotated through angle to fix the direction to A and measure l

along this direction to fix the position of A. This is known as setting out by angle and distance.

An alternative method would be to: compute l, WCB (ST) and WCB(SA) as per the first method.

Sight T from S and set the horizontal circle of the theodolite to read the WCB of ST. Rotate the

telescope towards point A until the WCB of SA is read on the horizontal circle.


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The telescope line of sight is no defining the direction of A and the exact position of A can be

fixed by measuring a horizontal distance l along this direction. This is setting out by bearing and

distance.

2. Intersection with two theodolites, from four control points using angles or bearings only.

Intersection is shown below.


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When setting out using coordinate-based methods with theodolites and tapes, the situation may

arise where there are no nearby control points available for this. This is overcome by establishing

a free station at any convenient place for setting out. This is shown in the next FIG and it is

essentially a resection.

Free station points are particularly applicable to large sites where the coordinates of prominent

features and targets on nearby buildings or parts of the construction are known.

The following steps are used when setting up a free station point:

-The theodolite is set up at some suitable place in the vicinity of the points which are to be set

out – hence the title free station as the choice of the instrument position is arbitrary.

-Any angular resection is carried out to fix the position of the free station point.

-The coordinates of the free station are calculated

Following this, setting out continues as before and the required design points are set out using

the theodolite at the free station point.

Although setting out can be conducted using theodolites, tapes (and levels) in what might be

sometimes called traditional methods, a lot of work on site is done using total stations and GPS

equipment.

When setting out by so-called traditional methods, direct methods of angle and distance are taken

to position structures and other works from nearby control points or from baselines.

Following this, offsets and profiles are put in place to define the main lines of a building and

provide vertical control for second stage setting out.

Despite their popularity on site, these well-established methods have the disadvantages that the

horizontal and vertical components of setting out have to be done separately (levelling must be

used for any heighting), they can be time consuming if a lot of points have to be set out, and they

require at least two people to do the setting out.


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Refernces

Lecturer notes

E books

http://en.wikipedia.org/wiki/Traverse_%28surveying%29

http://www.scribd.com/doc/229723904/Surveying

http://en.wikipedia.org/wiki/Traverse_%28surveying%29

http://www.engineeringcivil.com/theory/surveying/page/2

http://en.wikipedia.org/wiki/AutoCAD

http://en.wikipedia.org/wiki/Digital_geologic_mapping

www.scribd.com

www.slideshare.net

www.answers.com

www.civilengineering forum.com


http://www.slideshare.net/

http://www.scribd.com/

http://en.wikipedia.org/wiki/Digital_geologic_mapping

http://en.wikipedia.org/wiki/Traverse_(surveying)

http://www.scribd.com/doc/229723904/Surveying

http://en.wikipedia.org/wiki/Traverse_(surveying)

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