SCHOOL OF ARCHITECTURE, BUILDING AND DESIGN

BACHELOR OF QUANTITY SURVEYING (HONOURS)

MARCH 2016 INTAKE

SITE SURVEYING [QSB 60103]

FIELDWORK 1 REPORT

LEVELLING

GROUP MEMBERS:

NAME STUDENT ID

PANG KAI YUN 0319802

SAM WEI YIN 0320364

TRACE GEW YEE 0320269

YEO KAI WEN 0319844

LECTURER: MR. CHAI VOON CHIET

CONTENT

No. Content Page Number

1. Objectives 2

2. Introduction 3

3. Fieldwork 9

4. Raw Data 10

5. Adjusted Data 12

6. Discussion 14

7. References 15

1

OBJECTIVES

To enable to have a basic knowledge on how to set up the instruments such as

Automatic level (Auto- level), tripod stand, levelling rod rather than learning from the

books.

To apply the theories that had been taught in class.

To have an experience using Auto-level while setting up, collaborating, levelling and

recording the data that have been collected.

To learn how to analyse the data.

To identify the reduced level of each station and spot of relative height.

To determine the difference in height of the points.

To experience the life being as a quantity surveyor and expose the actual working

environment such as working under the hot weather in site.

To determine the error of the mis-closure in order whether is it acceptable or not on

the levelling calculations.

To know the precautions while using the Auto-level.

To boost the ability of teamwork while doing on fieldwork.

2

INTRODUCTION TO LEVELLING

What is levelling?

Levelling is the measurement of geodetic height which using an optical levelling

instrument and a level staff or rod that have a numbered scale. Common levelling

instruments include spirit level, dumpy level, digital level and laser level. Levelling is defined

as ‘an art of determining the relative height of different points on, above or below the

surface’. The principle of levelling is to obtain the horizontal line to which vertical distances of

the points. By using this instrument of the levelling, it can be used for design the highways,

sewers, railways and others. It can used to calculate the volume of earthwork and used as

site layout for new foundation, contouring drainage and estimate the fall of the pipe.

When do we level?

To determine the difference in height between two or more points.

To determine the height of discrete points.

To provide spot heights or contours on plan.

To provide the data for road cross-sections or volume of the earthworks.

To provide a level or inclined plane in the setting out of construction works.

3

Definition of Term Used in Levelling

Level surface

The surface that parallel to the mean spheroidal surface of the earth

Vertical line

Any line that lying vertically on the level surface.

Horizontal line

Any line that lying on horizontal plane which is straight line tangential to level line.

Vertical plane

A plane that containing a vertical line

Horizontal plane

A plane tangential to level surface at a point which is perpendicular to the direction of

gravity.

Datum

Any surface or line from which vertical distances are measured. There are two types

of Datum which is Ordnance Datum (O.D.) and Assume Datum (A.D.).

Bench-mark (B.M.)

A diced reference point of known elevation.

Temporary Bench- mark (T.B.M.)

Which is set up by the surveyor for is own task temporary

Reduce Level

A vertical distance of a point above or below the datum. The elevation of a point is

either plus or minus according to the point.

4

Line of Collimation (HI)

The line intersects with the cross hairs of the optical center of the object.

Backsight (BS)

The first reading of the instrument set up at the first point.

Intermediate Sight (IS)

The reading between the backsight and foresight.

Foresight (FS)

The final reading of the instrument.

Change point (C.P.)

A transfer point of the levelling. A new point which the previous point of the backsight

and foresight are taken.

Levelling Method

1. Height of Collimation Method

5

2. Rise and Fall Method

Apparatus Used For Levelling

Automatic level (Auto- level)

It is a professional levelling tool which is used by contractors, builders, land surveyors and

engineers who demand accurate the levelling survey. It is a self- levelling optical instrument

that measure horizontal planes and angles at distances no matter long distance or short

distance. This instrument is easy to set up. Before we use this instrument, we have to make

sure that the spirit bubble is in center of the black circle.

6

Adjustable Leg Tripod

This instrument is easy to set up due to each leg can be adjusted to the required height. The

function of this instrument is to ensure a stable instrument setup for reliable measurements.

If the instrument is moved, it must be set up again by loosen the screw and adjust it to make

sure that the levelling tripod is placed horizontally.

Optical Plummet

Is a device that used to center the instrument and used in place of a plumb bob to center

transits and the theodolites over a given point. It is preferred for its steadiness in strong

winds. It also protects the instrument from the accident like falling down. The device has a

lock below to lock the instruments that used in the fieldwork.

7

Horizontal Bubble Level

A tool for determine whether the surface is horizontal. The function of the horizontal bubble

level is same as the spirit level which has to ensure that the bubble is at the center of the

black circle. It is to check the accuracy of a level. The reading indicates to the surface which

is parallel to the horizontal plane.

Bar-Coded Level Rod

An instrument that used to determine the relative heights of the different points above the

datum area with the use of automatic level. It is a graduated wooden or aluminium rod.

8

FIELD WORK

9

RAW DATA

Height of Collimation Method

Back Sight (BS) Fore Sight (FS) Height of Collimation Reduced

LevelBench Mark

(BM)

0.805 100.805 100.000 BM 101

1.380 3.090 99.095 97.715 BM 1

1.360 1.385 99.070 97.710 BM 2

1.365 1.440 98.995 97.630 BM 3

1.485 1.435 99.045 97.560 BM 4

1.225 1.195 99.075 97.850 BM 5

1.305 1.275 99.105 97.800 BM 6

1.400 1.545 98.960 97.560 BM 7

1.205 1.155 99.010 97.805 BM 8

2.615 1.300 100.325 97.710 BM 9

1.370 0.355 101.340 99.970 BM 10

1.365 99.975 BM 101

- 15.515

- 15.54015.540 - 100.000

- 99.975

- 0.025 - 0.025

10

Rise and Fall Method

Back Sight (BS)

Fore Sight (FS)

Height of Collimation

Reduced Level

Bench Mark (BM)

Back Sight (BS)

0.805 100.000 BM 101

1.380 3.090 2.285 97.715 BM 1

1.360 1.385 0.005 97.710 BM 2

1.365 1.440 0.080 97.630 BM 3

1.485 1.435 0.070 97.560 BM 4

1.225 1.195 0.290 97.850 BM 5

1.305 1.275 0.050 97.800 BM 6

1.400 1.545 0.240 97.560 BM 7

1.205 1.155 0.245 97.805 BM 8

2.615 1.300 0.095 97.710 BM 9

1.370 0.355 2.260 99.970 BM 10

1.365 0.005 99.975 BM 101

- 15.515

- 15.54015.540

- 2.800

- 2.8252.825

- - 99.975

- 100.000

- 0.025 - 0.025 - 0.025

Mis-closure = 99.975 m - 100.000 m

= - 0.025 m

Maximum allowable error of closure = ± 12 √k = ± 12 √no .of setup

= ± 12 √11 = ± 39.799mm ( ± 0.0398m )

Therefore, the levelling is acceptable.

11

ADJUSTED DATA

Height of Collimation Method

Back Sight (BS)

Fore Sight (FS)

Height of Collimation

Reduced Level

CorrectionAdjusted Reduced

Level

Bench Mark (BM)

0.805 100.805 100.000 0 100.00000 BM 101

1.380 3.090 99.095 97.715 + 0.00227 97.71727 BM 1

1.360 1.385 99.070 97.710 + 0.00454 97.71454 BM 2

1.365 1.440 98.995 97.630 + 0.00681 97.63681 BM 3

1.485 1.435 99.045 97.560 + 0.00908 97.56908 BM 4

1.225 1.195 99.075 97.850 + 0.01135 97.86135 BM 5

1.305 1.275 99.105 97.800 + 0.01362 97.81362 BM 6

1.400 1.545 98.960 97.560 + 0.01589 97.57589 BM 7

1.205 1.155 99.010 97.805 + 0.01816 97.82316 BM 8

2.615 1.300 100.325 97.710 + 0.02043 97.73043 BM 9

1.370 0.355 101.340 99.970 + 0.02270 99.99270 BM 10

1.365 99.975 + 0.02497 99.99997 BM 101

- 15.515

- 15.54015.540

- 100.000

- 99.975

- 100.000

- 100.000

- 0.025 - 0.025 0.000

12

Rise and Fall Method

Back Sight (BS)

Fore Sight (FS)

Rise FallReduced

Level Correction

Adjusted Reduced

Level

Bench Mark (BM)

0.805 100.000 0 100.00000 BM 101

1.380 3.090 2.285 97.715 + 0.00227 97.71727 BM 1

1.360 1.385 0.005 97.710 + 0.00454 97.71454 BM 2

1.365 1.440 0.080 97.630 + 0.00681 97.63681 BM 3

1.485 1.435 0.070 97.560 + 0.00908 97.56908 BM 4

1.225 1.195 0.290 97.850 + 0.01135 97.86135 BM 5

1.305 1.275 0.050 97.800 + 0.01362 97.81362 BM 6

1.400 1.545 0.240 97.560 + 0.01589 97.57589 BM 7

1.205 1.155 0.245 97.805 + 0.01816 97.82316 BM 8

2.615 1.300 0.095 97.710 + 0.02043 97.73043 BM 9

1.370 0.355 2.260 99.970 + 0.02270 99.99270 BM 10

1.365 0.005 99.975 + 0.02497 99.99997 BM 101

- 15.515

- 15.54015.540

- 2.800

- 2.8252.825

- 100.000

- 99.975

- 100.000

- 100.000

- 0.025 - 0.025 - 0.025 0.000

Correction per set-up = Error of mis-closure ÷ Number of set-up

= (100.0000 - 99.975) ÷ 11

= + 0.00227 m

13

DISCUSSION

In this field work, we are required to measure the reduced level (RL) of 10 points

around the staff parking at Taylor’s University Lakeside Campus. The levelling process

begins with obtaining the backsight (BS) of BM101 and the foresight (FS) of BM 1. The

reduce level of BM101 is given which is 100.000m. Then, the auto level is shifted to another

point by following the checkpoint set on the plan of the carpark. After shifting 11 point, we

will get back to BM101. All the reading is collected and recorded down.

The reduced level of each staff station is being calculated through the two methods,

which are Height of Collimation Method and Rise and Fall Method. There is a mis-closure

error in the levelling process. The error of mis-closure we calculated is - 0.025m which is

within the ± 39.799mm acceptable range of mis-closure. Thus, the levelling is acceptable.

The error of mis-closure can be caused by the staff is not held vertically. If the staff is not

held vertical, the staff reading obtained is greater than the correct reading. The error also

can be caused by sun. Due to bright sunshine on the objective, staff reading cannot be

taken properly.

The reduced level is adjusted by using the loop mis-closure method. The correction

per set-up is calculated to distribute the error. The correction per set-up is + 0.00227 m. All

the reduced level are adjusted and the final reduce level is equivalent to the original given

benchmark level.

In conclusion, this fieldwork helps us to understand better on the concept of levelling.

We get to learn how to conduct a fieldwork and how to use the levelling apparatus. We really

enjoy the process of doing this fieldwork. This is a very great experience and it will definitely

help us in our future.

14

REFERENCES

Levelling Equipment in Surveying. (n.d.). Retrieved July 5, 2016, from

http://www.aboutcivil.org/levelling-equipment.html

Levelling Tutorials. (n.d.). Retrieved July 11, 2016, from http://www.levelling.uhi.ac.uk/

Surveying Equipment. (n.d.). Retrieved July 11, 2016, from

http://www.engineersupply.com/surveying-equipment.aspx

Welcome to Agriinfo.in. (n.d.). Retrieved June 11, 2016, from http://www.agriinfo.in/?

page=topic

What is levelling? - Surveying & Levelling. (2015). Retrieved June 11, 2016, from

http://www.civileblog.com/levelling/

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