Tizazu

                      SETUP LEVELLING

 

INTRODUCTION : Levelling (or leveling in American spelling) is a branch of surveying, the object of which is to

  1. Find the elevation of a given point with respect to the given or assumed datum.
  2. Establish a point at a given elevation with respect to the given or assumed datum.

 

OBJECTIVE  :The aim of this series of short tutorials is to guide you through the procedures for setting up an automatic level to make it ready for use, and reading the levelling staff.

MATRIALS USED: Tripod , leveling , staff ,note book

PROCEDURE:

  1. Position the tripod.Place the instrument on a stable surface in a position where you can see all the levels to be taken.  Try to position the instrument evenly between the points you need to sight. It is important to make sure you have a clear line of sight. 
  2. Adjust the tripod.Make sure that the tripod legs are spread evenly and the platform where the instrument will sit is fairly level.Adjust the tripod to suit your own height, then tighten the clamps. Remember not to use excessive force on the screws and clamps.
  1. Attach the levelling instrument.Lift the instrument using both hands and place screw is tightened can you release your grip on the instrument.Make sure the instrument is securely fixed.
  2. Adjust for parallax.Because people's eyesight varies, you may have to adjust the instrument so it will enable you to take accurate readings. If you find that when you look through the eyepiece, the cross-hairs (the cross in your view) seem to move against what you are looking at as you move your head, you will have to 'adjust for parallax'.You must correct this error, otherwise the readings you
  3. Level the instrument.You need to ensure the instrument is level. There are different ways of doing this, depending on the type of levelling instrument you are using.Many instruments have foot screws that you turn until the levelling bubble is in the centre.Some instruments have two separate levelling bubbles to help you level the instrument.
  4. Aim the instrument at the staff.1. Find the staff: look through the telescopic sights on top of the instrument to line it up with the staff.2. Zoom in: look through the eyepiece and zoom in on the staff by turning the focusing knobs on the side of the telescope until you can read the marks clearly.
  5. it on the tripod. Keep the instrument stable with one hand while you use the other to tighten the retaining screw in between the legs. Only when the retaining

RESULT:

 

BACK SIDE

INTERMIDATE SIDE

FRONT SIDE

RISE

FAIL

REDUCE LEVEL

REMARK

0+00

1.44

 

 

 

 

200

 

0+20

 

2.055

 

 

0.615

199.385

 

0+40

 

 

1.598

0.457

 

199.842

 

0+60

 

 

 

 

 

 

 

 

 Conclusion : as you see from the above table you can calc. the level of station with the difference of  in 20 metre gap .

                                                                                        

 

 

                                Authors :Tizazu Ejigu    feat      Tagesse Tinamo  

 

 
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