Ss field-data

TAYLOR’S UNIVERSITY | SABD | BQS

SCHOOL OF ARCHITECTURE, BUILDING AND DESIGN

BACHELOR OF QUANTITY SURVEYING (HONOURS)

QSB 60103 - SITE SURVEYING

FIELDWORK REPORT 1

LEVELLING

NAME STUDENT ID. MARKS LEE KAILYN 0320273

LIEW POH KA 0320424

DEONG KHAI KEAT 0320055

HUSNI NAIM BIN MOHD ZUHALI 0326126

TABLE OF CONTENT SITE SURVEYING | QSB 60103


CONTENT PAGES NO.

COVER PAGE 1

TABLE OF CONTENT 2

INTRODUCTION OF LEVELLING 3 - 4

APPARATUS USED 5 - 7

OBJECTIVE 8

LEVELLING FIELD WORK 9

FIELD DATA 10 - 11

ADJUSTED FIELD DATA 12 - 13

DISCUSSION 14 - 15

REFERENCES 16

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SITE SURVEYING | QSB 60103


INTRODUCTION OF LEVELLING

Levelling is the process of measuring, by direct or indirect methods, vertical distances in order to determine elevations. It is defined as “an art” of determining the relative height of different points on, above or below the surface. It is also the measurement of geodetic height using an optical levelling instrument and a level staff or rod having a numbered scale. Common levelling instruments include the spirit level, the dumpy level, the digital level, and the laser level.

Level SurfaceA level surface is defined as a curved surface which at each point is perpendicular to the direction of gravity at the point. The surface of a still water is a truly level surface. Any surface parallel to the mean spheroidal surface of the earth is, therefore, a level surface.

DatumA datum is an abstract coordinate system with a reference surface that provides known locations to begin surveys. In order to relate a series of heights to each other, they must be given a relative to common point or plane known as a datum.

There are two types of datum :

a) Ordnance Datum is a vertical datum which provides a basis for surveying and is referred to by all heights shown on Ordnance Survey maps.

b) Assumed datum is a datum transferred to a location near to the surveyed site when the Ordnance datum is inconvenient or impossible to relate to.

Bench-mark (B.M.)A bench-mark is fixed point and a post of other permanent mark established at a known elevation that is used as the basis for measuring the elevation of other topographical points.

Temporary benchmark (T.B.M.)A temporary benchmark (T.B.M.) is a fixed point with a known elevation used for level control during construction works and surveys. Temporary bench-marks can be set-up by a surveyor for his own works

3 SITE SURVEYING | QSB 60103


Reduced LevelA reduced level is the height of a point or object stated with reference to the selected datum for the work in hand. It is abbreviated to R.L. Provided that the starting point of the operations is a known or assumed R.L, then the R.L.’s of the various point of the site can be calculated from this R.L. and the staff readings taken at the various point. Back-sightIn levelling, the first sight or reading taken on a staff after setting up the level. A back-sight is always taken on a point of known or assumed height. It is abbreviated to B.S and is taken at the start of the work and at a change point.

Intermediate sightIn levelling, it is the staff reading taken on a point whose elevation is to be determined. All staff reading between B.S. and F.S. are intermediate sight.

ForesightIn levelling, it is the last sight or reading to be taken from one setting of the instrument. A foresight must be taken on a fixed point, which then become a benchmark.

Change Point (Turning Point)In levelling, it is a point at which two readings are taken on the staff, one before moving the instrument to a new position, and one after setting the instrument on the new position. It is often also termed a turning point and is abbreviated to C.P. or T.P.

Line of Collimation

It is a line joining the intersection of cross hairs of diaphragm to the optical center of object glass and continuation. It is also known as line of sight.

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APPARATUS USED

a) 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. The automatic level is known for providing users with consistent leveling accuracy every time while also being fast, low cost and easy to use. The automatic level is most commonly used in measuring, surveying, and setting horizontal and vertical levels. The instrument is normally situated on a tripod and then calibrated to a leveled position using leveling screws.

b) Optical Plummet

In surveying, 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.



5c) Adjustable Leg-tripod

A sturdy tripod in good condition is essential for obtaining accurate measurement. They provide a level base to easily mount and securely hold your instrument. The legs of tripod are adjustable and are made of wood, fiberglass or aluminium are adjustable for use in different types of surveying equipment.

d) Aluminium Levelling Rod

Levelling rods can be one piece, but many are sectional and can be shortened for storage and transport or lengthened for use. Aluminum rods may be shortened by telescoping sections inside each other. It also a graduated rod used in measuring the vertical distance between a point on the ground and the line of sight of a surveyor's level.



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e) Plumb bob

A plumb-bob or a plummet is a weight with a pointed tip on the bottom that is suspended from a string and used as a vertical reference line. It may also be used in surveying to sight a point on the ground that is not readily visible.

f) Spirit bubble

A spirit level, bubble level or simply a level is an instrument designed to indicate whether a surface is horizontal (level) or vertical (plumb). It is used in different types of instrument by the surveyor.



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OBJECTIVE

To find the elevation of given point with respect to some assumed reference line called datum

To determine the relative heights of different objects on or below the surface of the earth

To determine the undulation of the ground surface.

To establish point at required elevation respect to datum

To prepare a layout map for the water supply, sanitary and drainage system.

To determine the altitudes of different important points and to know the reduce levels of different points on or below the surface of the earth.

To prepare a map or plan to show the relative positions of the objects on the surface of earth. The map or plan is drawn to some suitable scale. It also shows boundaries of districts, states and countries. It also include details of different engineering features such as buildings roads, railways, dams, canals and many more.



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LEVELLING FIELD WORK



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FIELD DATA

Height of Collimation

BS IS FS Height of

Collimation

Reduced Level

Remarks

1.290 101.290 100.000 BM101:100.000

1.520 3.280 99.530 98.010 1

1.485 1.455 99.560 98.075 2

1.478 1.520 99.518 98.040 3

1.640 1.505 99.653 98.013 4

1.305 98.348 5

1.380 1.410 99.623 98.243 6

1.475 1.435 99.663 98.188 7

1.415 98.248 8

2.200 1.395 100.468 98.268 9

1.405 0.400 101.473 100.068 10

1.455 100.018 BM101

13.873 13.855 100.018 - 13.855 __ - 100.000__ 0.018__ 0.018__



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Rise and Fall Method

BS IS FS Rise Fall Reduced Level

Remarks

1.290 100.000 BM101:100.00

1.520 3.280 1.990 98.010 1

1.485 1.455 0.065 98.075 2

1.478 1.520 0.035 98.040 3

1.640 1.505 0.027 98.013 4

1.305 0.335 98.348 5

1.380 1.410 0.105 98.243 6

1.475 1.435 0.055 98.188 7

1.415 0.060 98.248 8

2.200 1.395 0.020 98.268 9

1.405 0.400 1.800 100.068 10

1.455 0.050 100.018 BM101

13.873 13.855 2.280 2.262 100.018-13.855_ - 2.262 _ -100.000_ 0.018_ 0.018_ 0.018_

Acceptable Misclosure: 12±/- √k ;

K = number of set-ups ;

12±/- √9 = ±/- 36mm ; SITE SURVEYING | QSB 60103


The levelling is acceptable.

11ADJUSTED FIELD DATA

Height of Collimation

BS IS FS Height of Collimation

Reduced Level

Adjustment Final Reduced Level

Remarks

1.290 101.290 100.000 100.000 BM101

1.520 3.280 99.530 98.010 - 0.0020 98.008 1

1.485 1.455 99.560 98.075 - 0.0040 98.071 2

1.478 1.520 99.518 98.040 - 0.0060 98.034 3

1.640 1.505 99.653 98.013 - 0.0080 98.005 4

1.305 98.348 5

1.380 1.410 99.623 98.243 - 0.0100 98.233 6

1.475 1.435 99.663 98.188 - 0.0120 98.176 7

1.415 98.248 8

2.200 1.395 100.468 98.268 - 0.0140 98.254 9

1.405 0.400 100.473 100.068 - 0.0160 100.052 10

1.455 100.018 -0.0180 100.000 BM101

13.873 13.855 100.018-13.855_ - 100.000_ 0.018_ 0.018_

Correction = Cumulative distance ÷ Total distance x Error

Correction per set up



= Error of misclosure ÷ Number of set up

= (100.000 – 100.018) ÷ 9

= - 0.0020 12

Rise and Fall Method

BS IS FS Rise Fall ReducedLevel

Adjustment FinalReduced

Level

Remarks

1.290 100.000 100.000 BM101

1.520 3.280 1.990 98.010 - 0.0020 98.008 1

1.485 1.455 0.065 98.075 - 0.0040 98.071 2

1,478 1.520 0.035 98.040 - 0.0060 98.034 3

1.640 1.505 0.027 98.013 - 0.0080 98.005 4

1.305 0.335 98.348 5

1.380 1.410 0.105 98.243 - 0.0100 98.233 6

1.475 1.435 0.055 98.188 - 0.0120 98.176 7

1.415 0.060 98.248 8

2.200 1.395 0.020 98.268 - 0.0140 98.254 9

1.405 0.400 1.800 100.068 - 0.0160 100.052 10

1.455 0.050 100.018 - 0.0180 100.000 BM101

13.873 13.855 2.280 2.262 100.018-13.855_ - 2.262_ - 100.000_ 0.018_ 0.018_ _ 0.018_



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DISCUSSION

For the first field work, we are assigned to conduct an auto-leveling in campus area. We are given 10 locations and required to calculate the reduced level of 11 locations included BM101 which located at the car park Taylor’s University Lakeside Campus. For the distribution of members, one person is assigned to hold leveling rod, one person is needed to record the data and other people are to confirm the reading from auto level and moving the instruments. Before we start our field work, we were given a demonstration on how to set up and read the readings of the leveling instrument to measure the height until we get the reduced level. We are allowed to assume a R.L. of 100.00m AOD at the lamp post which labelled as BM101. We are decided to make 9 set ups in the field work, which means we have to move the instrument for 9 times.

Firstly, the leveling instrument is set up between BM101 and Point 1. After the setup is done, we need to confirm the reading from the leveling rod and record it down. The instrument is then shifted to next setup location which between Point 1 and Point 2. Steps are repeated until the last point. The leveling instrument is set up in between 2 locations to get the height of 2 or 3 points once the instrument is set. In this field work, we have Back-sight readings, Intermediate sight readings and Foresight readings. Based on our group’s data, we have Intermediate sight readings. This is the reason which we have to get the readings for 3 points in 1 setup.

Once the field work is done, all readings have taken, we used two methods to calculate the reduced level which are Height of Collimation Method and Rise and Fall Method. After calculate the reduced level, the final reduced level is slightly more than the BM101 reduced level that given by lecturer. Therefore, we need to adjust it by using the loop misclosure method which is taught in class. To ensure the total readings are within the allowable error of misclosure, we are required to use the formula of Constant × √(Distance).

Constant × √(Distance)

= ± 12 √k

= ± 12 √9

= ± 36mm



In conclusion, the maximum acceptable error of closure is ± 36mm. If the answer is over ±36mm, we need to redo the fieldwork again. In our final result, we get the error of closure is 18mm, therefore, it is acceptable.

In this field work, we had a great experience on leveling instrument. We are able to measure the height by using the leveling instrument. We are also able to calculate the reduced level by using Height of Collimation Method and Rise and Fall Method. During the field work, we faced some problems while adjusting the spirit bubbles. Throughout 14

the whole field work, there are many setups and hence, we can master it. Although we had some misclosure mistakes on calculations, we are able to adjust it by using the method that was taught in class. This is a very great opportunity for us to handle a surveying instrument and we enjoyed the process during the fieldwork.



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REFERENCES

1) (Glossary, n.d.)http://www.vermessungsseiten.de/englisch/vermtech/guide/glossary.htm

2) (Civileblog, n.d.)http://www.civileblog.com/levelling/

3) (Dictionary of Construction, n.d.)http://www.dictionaryofconstruction.com/definition/optical-plummet.html

4) (Surveying Equipment and Level set-up, n.d.)http://www.boeingconsult.com/tafe/ss&so/survey1/Module4/equipment-s1.htm

5) (Reference, n.d.)https://www.reference.com/home-garden/automatic-level-42f9ad933d1043a0#

6) (Ben Meadow’s, n.d.)https://www.benmeadows.com/refinfo/techfacts/techpdf/survey_equipment_1360.pdf


https://www.benmeadows.com/refinfo/techfacts/techpdf/survey_equipment_1360.pdf

https://www.benmeadows.com/refinfo/techfacts/techpdf/survey_equipment_1360.pdf

https://www.reference.com/home-garden/automatic-level-42f9ad933d1043a0

https://www.reference.com/home-garden/automatic-level-42f9ad933d1043a0

http://www.boeingconsult.com/tafe/ss&so/survey1/Module4/equipment-s1.htm

http://www.boeingconsult.com/tafe/ss&so/survey1/Module4/equipment-s1.htm

http://www.dictionaryofconstruction.com/definition/optical-plummet.html

http://www.dictionaryofconstruction.com/definition/optical-plummet.html

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

http://www.vermessungsseiten.de/englisch/vermtech/guide/glossary.htm

http://www.vermessungsseiten.de/englisch/vermtech/guide/glossary.htm


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Education

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