Civil engineering usually requires the use of surveying. Without knowledge of levelling, a surveyor’s knowledge is incomplete. A common levelling instrument is the dumpy level. To become familiar with this levelling instrument and learn how to use it, carefully read the following article.
What is Dumpy Level?
The dumpy level is an optical surveying levelling instrument that consists of a telescope tube firmly secured in two collars attached to the stage by adjusting screws.
Dumpy level’s telescope can only rotate in a horizontal plane. Dumpy level is used to determine the relative elevation of different points on a surveying land.
William Gravatt, an English civil engineer, is credited with inventing the dumpy level. In 1832, while using the traditional Y level, he invented the dumpy level.
A builder’s level, also known as an automatic level, is a dumpy level.
Use of Dumpy Levels in Surveying
In the surveying of a construction site, the dumpy level is very important. Dumpy levels have become a popular choice among surveyors due to their accuracy and portability. In surveying, the dumpy level is primarily used for the following purposes:
- To determine the relative height and distance between various surveying land locations.
- To determine the relative distance between various surveying land locations.
- The primary goal of levelling on a construction site is to create a level and even surface.
- To find the height differences between two points.
- Using the principle of relativity, measure the height and distance of various surveying land locations.
- To determine the distance between various points on the surveying land.
- Creating construction levels and inclined surfaces.
- To trace the contours of a piece of land.
Advantages of Dumpy Level Survey
In surveying, the dumpy level is a widely used surveying instrument. The following are the benefits that have made the dumpy level so popular.
- There are fewer movable parts in this design.
- There will be fewer adjustments to make.
- It retains its two adjustments for a long time due to the rigidity of dumpy levels.
- Optical power is high.
Disadvantages of Dumpy Level Survey
Dumpy level has only a few limitations or drawbacks. These restrictions are listed below.
- Making precise measurements may be difficult for civil engineers.
- It is difficult to use.
Parts of Dumpy Levels
How to Use a Dumpy Level for Surveying?
The following instruments are required to conduct a dumpy level survey.
- Dumpy Level
- E meter staff or English staffs
A dumpy level survey will also necessitate the assistance of a third party. The following steps should be followed for a successful dumpy level survey once everything is ready.
- The tripod is initially set up properly to hold the dumpy level. Adjust the tripod height until it is level with your eyes. The tripod’s legs should then be adjusted to a balanced position in order to properly support the instrument. Finally, tripod legs should be pressed into the ground to secure them.
- The dumpy level instrument is fixed directly on top of the tripod. The device is secured to the tripod with a foot screw. Because the level head is so delicate, extra caution is required in this step.
- It is important to make the dumpy level completely horizontal in order for it to function properly. The dumpy level is levelled with the help of foot-screws (levelling screws). Adjust the levelling screws until the alignment bubble is in the centre of the marker.
- The telescope’s eyepiece is viewed by the operator.
- At the measurement point, an assistant holds an E metre or a staff vertically. This staff usually has imperial and metric measurements. The letter ‘E’ on the staff represents five centimetres.
- The instrument and staff are used to collect the elevations (levels) of various points.
- A benchmark with a known height determined by a previous survey, or an arbitrary point with an assumed height, is usually used as a starting point for measurement.
Md Shahin Akhter is a Civil Engineer from MIT and has more than 5 years of experience in Civil Engineering and Construction Department. Md Shahin Akhter is Civil Engineer in Nagar Parishad (Municipal Council), Supaul. He is Webmaster and Founder at ProCivilEngineer.com Civil Engineering Website.