ssreport1-141204022141-conversion-gate01.doc
TRANSCRIPT
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SCHOOL OF ARCHITECTURE, BUILDING AND DESIGN
BACHELOR OF QUANTITY SURVEYING (HONOURS)
QSB 60103- SITE SURVEYING
Fieldwork 1 Report
Levelling
Name Student ID Marks
SHARON CHOW CI YUNG 0313387
TAN CHUU YEE 0315097
MUHAMMAD HAZIQ BIN HAJI ABD ZARIFUL
0314131
PARHAM FARHADPOOR 0313698
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Table of Content
Content Page
Cover Page 1
Table of Content 2
1.0 Introduction to Levelling 3-4
2.0 Outline of Apparatus 5
2.1 Automatic Level 5
2.2 Adjustable Leg-Tripod 6
2.3 Optical Plummet 7
2.4 Horizontal Bubble Level 8
2.5 Bar- Coded Level Rod 8
3.0 Objectives 9
4.0 Field Data 10
4.1 Rise and Fall Method 10
4.2 Height of Collimation Method 11
5.0 Adjusted Data 12
5.1 Rise and Fall Method 12
5.2 Height of Collimation Method 13
6.0 Summary 14
7.0 References 15
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1.0 Introduction to Levelling
Levelling is the determination of the relative heights (altitudes) of the different points in
the area under survey, it is this information which, when coupled with that of the pan, enables a
section through the land and/or artefacts to be drawn (Clancy, 1991).
A horizontal line (or plane) of sight (line or plane of collimation) is established with a
telescope (fitted with cross-hairs) which can be turned about a vertical axis. The difference in
consecutive readings taken on a vertical staff gives the level difference between two points
which can be seen in the figure below.
Figure 1.0 Levelling
Source: http://www.colorado.edu/geography/courses/geog_2043_f01/lab4/diff.jpg
Backsight (B.S.) - The first reading from a new instrument position.
Intermediate Sight (I.S.) – Readings between the backsight (B.S.) and foresight (F.S.)
Foresight (F.S.) - The last reading from an instrument position.
There leveling has two type of layouts which are the rise and fall method and the height
of collimation method.
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Figure 1.1 Height of Collimation Method
Source: http://gmba-learning-gateway.co.uk/images/Height_of_Col.jpg?713
Figure 1.2 Rise and Fall Method
Source: http://constructionsite.org.uk/repository/resource/view_resource.php?
id=122&backname=study_unit
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2.0 Outline of Apparatus
2.1 Automatic Level - An Auto-Level is a Professional Leveling Tool used by Contractors,
Builders, Land Surveying Professionals, or the Engineer who demands accurate leveling every
time ( Engineering Supply, 2014).
Figure 2.0 Automatic Level
Source: http://www.engineersupply.com/Images/cst-berger-leveling-aligning-contractor-tools/
ES1008-CST-Berger-24X-SAL-Automatic-Level-55-SAL24ND-md.jpg
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2.2 Adjustable Leg-Tripod- Adjustable-leg tripods are the more common of the two in the
construction world, especially outdoors because of generally uneven terrain. The adjustable-leg
tripod is easier to set up on uneven ground because each leg can be adjusted to exactly the
height needed to find level, even on a very steep slope (Johnson Level, 2010).
Figure 2.1 Adjustable Leg- Tripod
Source: http://www.gotechequipment.com/laser%20images/GOtripod-1.jpg
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2.3 Optical Plummet - A device used in place of a plumb bob to center transits and theodolites
over a given point, preferred for its steadiness in strong winds (Dictionary of Construction.com,
2014).
Figure 2.2 Optical Plummet
Source:
http://www.sccssurvey.co.uk/media/catalog/product/cache/1/image/650x650/9df78eab33525d08
d6e5fb8d27136e95/l/e/leica_gdf111-1_tribrach_without_optical_plummet.jpg
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2.4 Horizontal Bubble Level - Tool for determining whether a surface is horizontal (The
Columbia Encyclopedia, 2014).
Figure 2.3 Horizontal Bubble Level
Source: http://image.made-in-china.com/43f34j00KvltAoQabOqR/Staff-Level.jpg
2.5 Bar- Coded Level Rod – To determine the relative heights of the different points in the area
under survey (Clancy, 1991).
Figure 2.4 Bar- Coded Level Rod
Source: http://www.testoon.com/images_produit/005838-full.jpg
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3.0 Objectives
To enhance the students’ knowledge in the leveling procedure.
To enable students to get hands-on experience in setting up and working with the auto-
level.
To determine the error of misclosure in order to determine whether the levelling is
acceptable or not.
To allow students to apply the theories that had been taught in the classes in a hand- on
situation such as making adjustments for each reduced level of every single staff station
in order to obtain the most accurate reduced levels.
To identify the reduced level of each staff station.
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4.0 Field Data
4.1 Rise and Fall Method
BS IS FS Rise Fall R.L. Remarks
1.458 100.000 BM1
1.390 3.679 2.221 97.779 TP A
1.619 1.502 0.112 97.667 TP B
1.243 1.535 0.084 97.751 TP C
1.553 1.488 0.245 97.506 TP D
1.276 1.269 0.284 97.790 TP E
1.274 1.300 0.024 97.766 TP F
1.627 1.436 0.162 97.604 TP G
3.571 1.489 0.138 97.742 TP H
1.348 1.338 2.233 99.975 TP I
1.329 0.019 99.994 BM1
∑BS=16.359 ∑FS=16.365 ∑Rise=2.758 ∑Fall=2.764
Arithmetical Check :
∑BS-∑FS= ∑Rise-∑Fall= Last Reduced Level Reading- First Reduced Level Reading
16.359-16.365 = 2.758-2.764 = 99.994-100.000
-0.006 = -0.006 = -0.006
Acceptable Misclosure= 12+/- √k
K= the number of set-ups
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12+/-√10= +/-37.947mm∴ The levelling is acceptable
4.2 Height of Collimation Method
BS IS FS Height of Collimation R.L. Remarks
1.458 101.458 100.000 BM1
1.390 3.679 99.169 97.779 TP A
1.619 1.502 99.286 97.667 TP B
1.243 1.535 98.994 97.751 TP C
1.553 1.488 99.059 97.506 TP D
1.276 1.269 99.066 97.790 TP E
1.274 1.300 99.040 97.766 TP F
1.627 1.436 99.231 97.604 TP G
3.571 1.489 101.313 97.742 TP H
1.348 1.338 101.323 99.975 TP I
1.329 99.994 BM1
∑BS=16.359 ∑FS=16.365
Arithmetical Check :
∑BS-∑FS= = Last Reduced Level Reading- First Reduced Level Reading
16.359-16.365 = 99.994-100.000
-0.006 = -0.006
Acceptable Misclosure= 12+/- √k
K= the number of set-ups
12+/-√10= +/-37.947mm
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∴ The levelling is acceptable.
5.0 Adjusted Data
5.1 Rise and Fall Method
BS IS FS Rise Fall R.L. Adj. Final
R.L.
Remarks
1.458 100.000 100.0000 BM1
1.390 3.679 2.221 97.779 +0.0006 97.7796 TP A
1.619 1.502 0.112 97.667 +0.0012 97.6682 TP B
1.243 1.535 0.084 97.751 +0.0018 97.7528 TP C
1.553 1.488 0.245 97.506 +0.0024 97.5084 TP D
1.276 1.269 0.284 97.790 +0.0030 97.7930 TP E
1.274 1.300 0.024 97.766 +0.0036 97.7696 TP F
1.627 1.436 0.162 97.604 +0.0042 97.6082 TP G
3.571 1.489 0.138 97.742 +0.0048 97.7468 TP H
1.348 1.338 2.233 99.975 +0.0054 99.9804 TP I
1.329 0.019 99.994 +0.0060 100.0000 BM1
Correction per set-up
= Error of misclosure ÷ Number of set up
= (100.0000-99.9940)÷10
= +0.0006 m
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5.2 Height of Collimation Method
BS IS FS Height of
Collimation
R.L. Adj. Final R.L. Remarks
1.458 101.458 100.000 100.0000 BM1
1.390 3.679 99.169 97.779 +0.0006 97.7796 TP A
1.619 1.502 99.286 97.667 +0.0012 97.6682 TP B
1.243 1.535 98.994 97.751 +0.0018 97.7528 TP C
1.553 1.488 99.059 97.506 +0.0024 97.5084 TP D
1.276 1.269 99.066 97.790 +0.0030 97.7930 TP E
1.274 1.300 99.040 97.766 +0.0036 97.7696 TP F
1.627 1.436 99.231 97.604 +0.0042 97.6082 TP G
3.571 1.489 101.313 97.742 +0.0048 97.7468 TP H
1.348 1.338 101.323 99.975 +0.0054 99.9804 TP I
1.329 99.994 +0.0060 100.0000 BM1
Correction per set-up
= Error of misclosure ÷ Number of set up
= (100.0000-99.9940)÷10
= +0.0006 m
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6.0 Summary
In this fieldwork, the reduced level of Bench Mark (BM) 1 is given which is 100.00m. The
leveling process begins with obtaining the backsight (BS) of BM1 and the foresight (FS) of
turning point (TP) A. Then the auto level is shifted to obtain the BS of TP A and the FS of TP B.
This process is repeated by shifting the auto level to obtain the BS and FS of the following staff
stations and lastly go back to BM1 to obtain its FS in order to calculate the error of misclosure.
We used both the rise and fall method and the height of collimation method to calculate
the reduced level of each staff station. The error of misclosure was -0.006mm and the
acceptable range of error of misclosure was calculated using the 12+/- √k formulae where k
represents the number of set-ups, and the acceptable range of error of misclosure is +/-
37.947mm. Thus, our leveling is acceptable.
To distribute the error, the correction per set-up is calculated using the following
formulae:
Correction per set-up
= Error of misclosure ÷ Number of set up
The correction per-set up is +0.0006m and is cumulative as shown in the table provided
in the adjusted data section.
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7.0 References
Clancy, J. (1991). Site Surveying and Leveling. (2nd ed). London, United Kingdom: Arnold.
Dictionary of Consturction.com. (2014). optical plummet. (Website). Retrieved on 13th
November, 2014 from http://www.dictionaryofconstruction.com/definition/optical-
plummet.html
Encyclopedia.com.(2014). spirit level. (Website). Retrieved on 13th November, 2014, from
http://www.encyclopedia.com/topic/spirit_level.aspx
EngineerSupply. ( 2014). Automatic Levels. (Website). Retrieved on 13th November, 2014, from
http://www.engineersupply.com/automatic-levels.aspx
Johnson Level & Tool. (2014). What is a Tripod? How do Tripods for Laser Levels Work?
Retrieved on 13th November, 2014 from
http://www.johnsonlevel.com/News/WhatisaTripodHowdoTripods
Macbain, G. (n.d.). Book Levels. (Website). Retrieved on 13th November, 2014 from
http://constructionsite.org.uk/index.php?/content/view/150/7ef605fc8dba5425d6965f
bd4c8fbe1f/open/cab34bec95719831380345d7068f5457/unit/29/key/
6ea9ab1baa0efb9e19094440c317e21b/chapter/3
Muskett, M. (1995). Site Surveying. (2nd ed). Oxford, United Kingdom: Blackwell Science Ltd.
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