site surveying report 2

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SCHOOL OF ARCHITECTURE, BUILDING AND DESIGN BACHELOR OF QUANTITY SURVEYING (HONOURS) QSB60103103946-M - SITE SURVEYING Fieldwork Report 2 TITLE: Traverse GROUP MEMBERS: ID 1. Yeo Dor Een 0316224 2. Welson Lum Wei Jiunn 0319514 3. Yap Jia En 0319550 4. Yong Sing Yew 0318766 1

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Page 1: Site surveying report 2

SCHOOL OF ARCHITECTURE, BUILDING AND DESIGN

BACHELOR OF QUANTITY SURVEYING (HONOURS)

QSB60103103946-M - SITE SURVEYING

Fieldwork Report 2 TITLE: Traverse

GROUP MEMBERS: ID1. Yeo Dor Een 0316224

2. Welson Lum Wei Jiunn 0319514

3. Yap Jia En 0319550

4. Yong Sing Yew 0318766

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Table of Content

Content PagesCover Page 1

Table of Content 2Introduction to Traverse 3-5

Introduction of Apparatus 6-7Data and Results 8-14

Reference 15

Introduction to TraversingWhat is Traversing?

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Traversing is a survey which involves a connected sequences of line whose

length and direction are measured. It involves placing survey points along a

line or path of travel, and then using back the previously surveyed points as a

base for observing next point. It is a common method of control surveys

performed by surveyors in the field.

Objectives

The objectives of this field work 2 (Traverse) is to:

a) To give a proper understanding of traversing

b) To understand the method used in traversing

There are two type of traverse which are:

(a) Open Traverse:

An open traverse start on a known point and finished on an unknown

point. This lack of geometric closure means that there is no geometric

verification possible with respect to the actual positioning of the traverse

stations. An open traverse is commonly used for exploratory purpose such as

mine surveying. It should generally not be used in civil engineering works

unless situation needed.

Figure 1: Example of Open Traverse

(b) Closed traverse:

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A closed traverse is one enclosing a defined area and having a

common point for its beginning to end. It starts and ends at the same point,

forming a closed geometric figure called a polygon. This type of traverse was

the type that we doing for our field work.

Figure 2: Example of Closed Traverse

Selection of Station

i. The select station positions should be as close as possible to the

objects to be located.

ii. The selected station should be mark out clearly by anything which is

suitable.

iii. The chosen point should not be blocked by anything so that we can get

the reading from the other point.

iv. Too many points will increase the time and cost of the survey. However

too less points may provide a not sufficient control for the project.

Bearings

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A bearings are never greater than 90 °. It is referenced from north or south and the angle to the east or west from the north-south meridian.

Azimuths

An azimuths range from 0 to 360°. It is an angle measured clockwise from any reference meridian.  

Figure 3: Bearings and Azimuths

Acceptable Misclosure

Commonly for land surveying, an accuracy of about 1:3000 is typical. An accuracy of at least 1:5000 would be required for third-order control traverse surveys. The acceptable misclosure can be measured by:

Accuracy = 1: (P/EC)

P= Perimeter of the Entire Traverse

Ec= The Total Error

Introduction of Apparatus

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Theodolite

A theodolite is a surveying instrument with a rotating telescope for measuring

horizontal and vertical angles. Theodolite are mainly used for surveying and

have been adapted for specialized purposes in fields

like meteorology and rocket launch technology. When the telescope of the

theodolite is pointed at a target object, the angle of each of these axes can be

measured with great precision, typically to seconds of arc.

Figure 1: Theodolite

Tripod

A surveyor’s tripod is an instrument used to support any surveying instrument

for example theodolite and others. The head of the tripod supports and lock

the instrument while the feet are spiked to anchor the tripod to the ground. It

provides stability against downward forces and horizontal forces and

movements about horizontal axes. We need to set up the theodolite on the

tripod.

Figure 2: Tripod

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Leveling Rod

A levelling rod also called levelling staff. It is a graduated wooden or

aluminium rod, used with a levelling instrument to determine the different in

height between points or heights or points above a datum surface. The

levelling rod we used in fieldwork was aluminium rod. We get the height of the

theodolite after set up everything and mark the height of it on the levelling rod

with rubber band. In this fieldwork we used 2 levelling rod.

Figure 3: Levelling Rod

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Data and ResultsField Data

Point

Stadia Reading 1:

Stadia Reading 2: Horizontal Angle:

A T - 148.5 T - 157 168°44’40” /2M - 143.0 M - 143 =84°22’20”B - 137.5 B - 130

V - 89°25’00” V - 9

0°01’20”

B T - 160 T - 151.5 144°44’40” /2M - 147 M - 147.0 =72°22’20”B - 133 B - 141.5

V - 89°56’00” V - 8

9°42’00”

C T - 147.5 T - 154.0 224°34’20” /2

M - 142.5 M - 142.5 =112°17’10”

B - 137.5 B - 131.0

V - 90°14’20” V - 8

9°47’40”

D T - 153.5 T - 147.5 181°51’40” /2M - 142.0 M - 142.0 =90°55’50”B - 130.5 B - 136.0

V - 90°11’40” V - 9

0°32’00”

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Compute The Angular Error & Adjust The AnglesSum of interior angles :

(n-2) x 180 °= (4-2) x 180°

= 360°

Total angular error = 360°- 359°57’40”= 0°2’20”

Therefore, error per angle = 4 = 0°0’35”

Station Field Angles Correction Adjusted angles

A-B 84°22’20’ 0°0’35” 84°22’55’’

B-C 72°22’20’’ 0°0’35’’ 72°22’55’’

C-D 112°17’10’’ 0°0’35’ 112°17’45’

D-A 90°55’50’’ 0°0’35’’ 90°56’25’’

Sum 359°57’40’’ 0°2’20” 360°00’00’’

DistanceD= K s sin2(θ)

Distance A-B = 100 (157-130) sin2 (90°01’20”) = 27.00m

Distance B-C = 100 (151.5-141.5) sin2 (89°42’00”) = 10.00m

Distance C-D = 100 (154-131) sin2 (89°47’40”) = 23.00m

Distance D-A = 100 (147.5-136.0) sin2 (90°32’00”) = 11.50m

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B

10m

C 72°22’55”

112°17’45”

23m 27m

90°56’25” 84°22’55’’

D A

11.5m

(Not to scale)

Azimuth

Station D - A : 90°56’25’’

Station A - B : 270° + 84°22’55” + 0°56’25” = 355°19’20”

Station B - C: 180° + (72°22’55”- 4°40’40”) = 247°42’15”

Station C - D: 180°

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Computations For Latitude and Departure

Figure 1.1: Algebraic sign convention for latitude and departure

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Computations For Latitude and Departure

Length

Cos Sin Latitude Departure

Station

L(m) Bearing Cos θ

Sin θ L Cos θ L Sin θ

A-B 27 N 4°40’40” W 0.997 0.082 +26.919 -2.214

B-C 10 S 67°42’15’’ W 0.379 0.925 -3.790 -9.250

C-D 23 S 0° 00’00” E/W

1.000 0.000 -23.000 0.000

D-A 11.5 S 89°03’35’’ E 0.016 1.000 -0.184 +11.500

Total 71.5 -0.055 0.036

Accuracy = 1 : (P/Ec)

P = Total Length

Ec = [ (sum of latitude)2 + (sum of departure)2 ]1/2

Accuracy = 1 : (71.5 / 0.0657) = 1 : 1088.

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Adjusted Course Latitudes and Departures

The Compass Rule

Correction = – [ ∑∆y ] / P x L or – [ ∑∆x ] / P x L

Where,

∑∆y and ∑∆x = The total error in latitude and departure

P = Total length of perimeter of the traverse

L = Length of a particular course

Unadjusted Correction Adjusted

Station

Latitude Departure

Latitude Departure Latitude

Departure

A

+26.919 -2.214 0.020 -0.014 26.939 -2.228

B

-3.790 -9.250 0.008 -0.005 -3.782 -9.255

C

-23.000 0.000 0.018 -0.012 -22.982 -0.012

D

-0.184 +11.500 0.009 -0.005 -0.175 11.495

A

SUM -0.055 0.036 0.055 -0.036 0.000 0.000

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Computation of Station Coordinates

Station Adjusted Latitude

Adjusted Departure

N Coordinate Latitude (y-axis)

E Coordinates Departure(x-axis)

A 100.000 (Assumed)

100.000 (Assumed)

26.939 -2.228

B 126.939 97.772

-3.782 -9.255

C 123.157 88.517

-22.982 -0.012

D 100.175 88.505

-0.175 11.495

A 100.000 100.000

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Discussion

In this fieldwork, we were required to carry out a closed loop

traverse survey. The location was at the car park as well. Closed loop

traverse is a loop traverse starts and ends at the same point, forming a

closed geometric figure called a polygon which is the boundary lines of a

tract land. The equipment that we used for this fieldwork is theodolite,

tripod and plumb bob. Before starting the fieldwork, we roughly marked

four points of stations which are station A, B, C and D by using masking

tape.

After set up of theodolite, we used it to measure the angles of four

stations (A, B, C and D) as our field data. The theodolite is placed at

point A, and the horizontal angle of point A is achieved by reading the

theodolite through point D to B. The angles of the theodolite must be read

from left to right in order to obtain an accurate reading. This process is

repeated at each of the points. Horizontal and vertical angles are

recorded. We also have to record the top, middle and bottom stadia

readings. After the fieldwork is done, calculation of data is carried out to

obtain results.

Our group has faced some problems in this project. We carried out

two attempts in this fieldwork since the first attempt has failed to get an

accurate result. With the help from our lecturer in the second attempt, we

were able to solve the problems and get the result efficiently.

Furthermore, we also learnt that group work is very important in

the fieldwork. The survey could not be done smoothly by the absence of

any one of our group members. Participation of every group members is

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much appreciated that we were able to finish the fieldwork and obtain the

result on time.

Last but not least, thank to our lecturer, Mr. Chai who has taught us

on how to use a theodolite. This fieldwork has been completed

successfully by us with the patience and guidance from Mr. Chai.

Overall, this fieldwork has taught us a lot of hands-on knowledge about

the surveying.

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