Labsheet ukur aras two peg test PDF

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Summary

Levelling Two Peg Test lab sheet...

Description

CEN DEPAR

DIES ERING Y

LABORATORY SHEET

Subject code

DAC 20503

Practical code

MG 02

Practical name

Levelling

Course code

2DAA

CENTR TUDIES DEPARTMENT OF CIVIL ENGINEERING GEOMATIC LABORATORY Subject Code Practical Name

DAC 20503 LEVELLING (ESTABLISH

Course Code Practical Date Group Group Leader Group Members

Lecture name / Instructor / Tutor Marks

Comments

TBM) DIPLOMA IN CIVIL ENGINEERING (2DAA) 22 OCTOBER 2017 9 AMIR SYARIFUDDIN BIN SUHAIMI (AA161988) 1. MOHD HAZIQ FITRI BIN HISHAM (AA161871) 2. MUHAMMAD NUR IZZUDIN BIN ROSLAN (AA161476) 3. NUR HIDAYU BINTI SAAD (AA161988) 4. FATIN NADIA BINTI AZMAN (AA160306) 5. SITI KHADIJAH NAJWA BINTI CHE ZAINI (AA160306) SITI NOORAIIN BINTI MOHD RAZALI

Introduction Objective Theory Instrument Procedure Data / Table Data analysis Discussion Presentation / Ploting Conclusion/ Recommendation Reference Total mark Accepted Seal

Centre For Diploma Studies Department of Civil Engineering Levelling (Two Peg Test)

/5% /5% / 10 % /5% /5% / 10 % / 20 % / 15 % / 10 % / 10 % /5% / 100 %

Sheet No. Edition Checking No. Effective date Revised date

1/4

June 2012

1.0

Introduction Two peg test is a surveying operation carried out to determine whether the levelling bubble and telescope line of sight are parallel.

2.0

Aim Peg Test is a surveying operation carried out to determine if the leveling bubble (bubble axis) and telescope line-of-sight (line of collimation) are parallel

3.0

Equipments Level and Tripod (1 set) Staff (2 sets) Staff bubble (2 sets) Tape (1 set)

3.1 3.2 3.3 3.4 4.0

Procedures Each group will be required to perform a peg test to check the instrument. Each person in the group should record the results of the peg test in their own field book. 4.3 Set out and mark on the ground (with wooden pegs driven into the earth, or roofing nails in tar) two point some 30 m apart. 4.4 Set up instrument midway between two pegs [Figure 3.1].

4.1 4.2

Figure 3.1: The first set up

Centre For Diploma Studies Department of Civil Engineering Levelling (Two Peg Test)

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Edition Checking No. Effective date

June 2012

Revised date 4.5 Read staff on each peg (back sight and foresight), and calculate height difference. 4.6 Next, move instrument about L/10 = 6 m beyond one of the pegs (normally fore staff

position), [Figure 3.2]. 4.7 Read staff on each peg again, and calculate height difference

Figure 3.2: The second set up

5.0

Observations Data and Analysis Reading Staff B (S1)

Reading Staff A (S2)

Height difference = m

Reading Staff B (S1’)

Reading Staff A (S2’)

Height difference = m’

First set up

Second set up Difference (m – m’)

30 m

60 m

5.0 If m=m’ then the instrument is OK! 5.1 Acceptable error: 5mm The error is called collimation error.

Centre For Diploma Studies Department of Civil Engineering Levelling (Establish TBM)

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Edition Checking No. Effective date Revised date

June 2012

6.0 Discussion From our discussion, the acceptable error is not more than 5mm. If there is no error that’s ean the instrument is in a good condotion. In our practical we ge the error 5mm. This error is acceptable since it is not more that 5mm. These error occur because of carelessness of the person that take the staff reading. These error can be avoid by repeating the test and make sure we know how to read the staff to avoid mistake or any error. These error olso occur because of the equipment and the environment. These error can be avoid by making sure the distance between level and staff is the same between staff A and staff B during the test. The bubble in level and staff must be accurate before taking the reading to avoid any error. Lastsly we need to know how to use the level to avoid any mistake while taking the staff reading. 7.0 Conclusion

Centre For Diploma Studies Department of Civil Engineering Levelling (Two Peg Test)

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Edition Checking No. Effective date Revised date

June 2012

9.2 Booking Procedures 9.2.1 The Rise and Fall Method The terms that are commonly used in the Rise and Fall Method are: BS = Backsight, FS = Foresight, IS = Intermediate Sight, and RL = Reduced Level.

9.3 Reduction (Calculation) Procedures 9.3.1 Checks your survey accuracy, and should be within tolerances given below or suitable for your project. This check should be applied before your leave the job 9.3.2 The following check the arithmetic of your level reductions and must be exact: BS - FS = Rise - Fall (BS) – (FS) = RL (last BM) – RL (start BM) 9.3.3 Misclosure should be: (20K) mm, where K is the length of the traverse in km. 9.3.4 For example, misclosure is +30 mm and the length of the loop is 0.7 km. Hence the misclosure limit is 200.7 = 17 mm. Therefore, the misclosure of +30 mm is too big (means that the leveling work is not accepted)....