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Two Peg Test

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FIELD WORK TITLE
FIELD WORK TITLE

Two peg test

INTRODUCTION
INTRODUCTION

Two Peg Test is a surveying operation carried out to determine whether the leveling bubble and telescope line of sight are parallel.

OBJECTIVE
OBJECTIVE

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.

TOOLS

TOOLS

Dumpy levelTripod

Staff Tape

Bubble staff

FIELD WORK PROCEDURE
FIELD WORK PROCEDURE

i. Each group is required to perform a peg test to check the instrument. ii. Each person in the group is record the results of the Peg Test in their own field book. iii. Set out and mark on the ground (with wooden pegs driven into the ground) two point some 15 m apart. iv. Instrument is set up midway between two point A and B. v. Staff is read on each staff point A and point B and the height difference is calculated. Made sure the bubble staff is center vi. Next, instrument is moved about 5m behind the point B. and staff at point A and point B is read. vii. Record the data.

RESULT
RESULT

Point A1 – point B1
=1.312 – 1.310
=0.002m
Point A2 – point B2
=1.239 – 1.238
=0.001m
STN 1 – STN 2
= 0.002 – 0.001
=0.001m
=1mm
∆ < ± 2mm

ANALYSIS
ANALYSIS

The error is ±2mm so it can be accepted. The instrument is in good condition and can used in field work.

CONCLUSION
CONCLUSION

The instrument can be determined the leveling bubble (bubble axis) and telescope line-of-sight (line of collimation) are parallel.