Levelling in Surveying Using Dumpy Level

Levelling deals with measurements in a vertical plane, making sure same points are verify on the horizontal plane.

There are many levelling instruments that are used in taking level, but I will be discussing about the most common of all “Dumpy Level”.

Dumpy Level, also known as builder’s Auto level or Automatic Level is an optical instrument used to establishing same points in the same horizontal plane. It is used in surveying and building with a vertical staff to measure height differences and to transfer, measure and set heights.

While using a dumpy level, always understand that, the higher the ground level, the lower your readings on the E meters Staff. And the lower the level the ground level, the higher your readings on the E meters Staff.

 

STEP IN MAKING USE OF THE DUMPY LEVEL

[1] SET YOUR TRIPOD NEAR THE POINT TO MEASURE

Place your tripod on a patch of flat, clear ground that sits between your benchmark location and the spot you want to measure. Then, undo the latches on your tripod’s legs and extend each leg out. Adjust the legs until your tripod is completely level, then close each latch. To measure the area properly, make sure you set up in a spot that’s slightly higher than your benchmark location.

CHECK OUT  Formwork in Construction

 

[2] CONNECT YOUR TELESCOPE TO THE TRIPOD STAND

Screw your dumpy level onto the tripod’s base plate, then connect the base plate to the main tripod body. Once the instrument is securely attached, turn the dumpy level’s telescope so that it sits parallel with 2 of the device’s leveling screws.

 

[3] LEVEL THE TELESCOPE BY ADJUSTING THE 3 FOOT SCREW {LEVELLING SCREWS}

Your aim is to adjust the spirit level to the centre, Look for the bubble level located somewhere on your device. When you find it, grab the 3 leveling screws of the device’s telescope and twist them in opposite directions. Do this until the bubble sits in the exact center of the level.

 

[4] TURN YOUR TELESCOPE 180° TO CHECK FOR THE LEVEL CALIBRATION.

After making your initial leveling adjustments, return your telescope to its starting position and check that the spirit level still sits in the center of the level. If it does, turn the telescope 180 degrees and check the level again. You can focus the device once all 3 positions show the bubble in the center of the level.

CHECK OUT  Retaining Wall, Different Types of Retaining Walls & Their Area of Application

 

[5] POSITION YOUR E STAFF ON LEVEL POINT YOU WANT TO TRANSFER.

While using a dumpy level, have it in mind you must have another person with you to hold the E staff. Make sure the person holding the staff position it at at angle of 90° to the ground level. This is possible making use of the spirit level on the staff.

 

[6] CHECK THROUGH THE EYEPIECE LOCATING YOUR READINGS ON THE E STAFF.

While doing this you need to make use of two screws. The Rotating Screws, 2 in number for rotating the  telescope in 360°and for easy reading of the E staff. The Focusing Screw give a clear view of the staff for proper reading.

 

[7] TAKE YOUR READING AND TRANSFER SAME VALUE YOU READ TO ANOTHER POINT.

Assuming the level you want to transfer a point of 15.5 level to another point. Take your E Staff to the point, if you got a value lower than 15.5, that means the ground is higher, but if you got a value higher than 15.5, that means the ground is lower.

CHECK OUT  Different Types & Sizes of Aggregate for Concrete

 

Love this post and you love to get a copy
Click on the button below to Get the PDF file and Read Offline.

Enter your Comment....

This site uses Akismet to reduce spam. Learn how your comment data is processed.