Constructing Benchmarks on Site

Today, I want to share a moment from the construction site as we work on something very important in surveying which is constructing a benchmark. Though we've constructed benchmarks from 5+000 chainage to chainage 22+500 which took us three weeks but excavators had already destroyed some which it's mandatory for us to construct their replacement.

What we are doing presently is preparing and constructing this point to serve as a reliable reference for elevation during the road construction project. A benchmark is not just an ordinary point on the ground. It is established to provide a known level from which surveyors can transfer and determine the elevations of other points on the site. The point helps the necessary department to know the maximum level they're going to work on. To construct a benchmark, we need cement, stone dust, sharp sand, metal, water, hammer and so on.

We make use of GPS to determine the chainage and exact point to construct the BM. During the construction process, we have to make sure the point is properly positioned, stable and clearly marked. The surrounding soil has to be prepared carefully so that the reference point can remain firm and useful throughout the project.

Once the benchmark is properly established and its Reduced Level (RL) is known, it can be used for various surveying activities. We can use it to transfer levels, check existing ground levels, establish formation levels, determine Final Road Levels (FRL), and control the levels of drainage, culverts and other road structures.

The red and white tape around the wooden stakes helps make the point visible and easier for the surveying team to identify on site we do call it caution tape. There are some chainages where we have to cut and enter bushes to construct the BM.This is one of those moments that shows that surveying starts from the ground up. Before accurate levels can be transferred across a construction project, there must be a reliable reference point. This is what I'm experiencing presently in another profession I never thought of finding myself but I have to do it just to earn a living. Surveying job varies and as time goes on the time of few tasks will come where there will be time to rest.