What Is Chain Surveying In Civil Engineering?
What Is Chain Surveying In Civil Engineering?
Chain surveying is a common practice in civil engineering and involves making only linear measurements in the field. This type of survey is suitable for smaller areas with simple details, as well as flat terrains.
Chain surveying follows the principle of Chain Triangulation, which divides the area to be surveyed into several small triangles. Measurements from these triangles are then combined together to form a complete picture of an area or region being studied.
Furthermore, chain surveying is conducted with special instruments such as chord chains, ranging rods, and offset rods that allow for accurate measurement of distances both horizontally and vertically.
What Is A Chain In Civil Engineering?
A chain in civil engineering is a measuring instrument used in surveying which is formed by 100 links of 4mm galvanized mild steel wire.
These chains are used to determine and calculate the measurements, areas, and distances between two points, lines, angles, and other shapes as well as heights and depths.
The chain is held together with a toggle joint at one end which allows it to be measured out in any direction. It also has wooden or metal handles and a movable pointer at the other end that helps the user mark and measure accurately.
Chains are highly versatile pieces of equipment due to their accuracy and adaptability which makes them essential pieces of equipment for any surveyor’s toolkit.
What Is The Aim Of The Chain Survey?
The aim of chain surveying is to quickly and accurately measure the length of lines marked on the field, as well as to measure details through the use of offsets and ties from those lines.
It is a widely used form of detail surveying, allowing for rapid assessment and analysis of data collected in the field. Overall, it provides a faster and more cost-effective way to acquire survey data.
What Is The Equipment Used In Chain Surveying?
Chain surveying involves the use of various equipment such as a prismatic compass, tripod, tape, chain, arrows, and ranging rods. The prismatic compass is used for finding bearings and for taking angular measurements.
The tripod helps in setting up the instrument at various stations with utmost accuracy. The tapes are used for measuring horizontal distances between two points whereas the chain is generally made of brass or steel links which are joined together to form a chain of known length.
Arrows and ranging rods are used as reference points and for transferring linear measurements from one point to another. All these tools make up the equipment required to perform chain surveying efficiently.
What Are The Steps Involved In Chain Surveying?
Chain surveying consists of the following steps: reconnaissance, marking stations, making reference sketches, and running survey lines.
During reconnaissance, a preliminary inspection of the area being surveyed is conducted. Then stations are marked with a ranging rod or wooden peg, or nails or spikes if it is a hard surface area or embedding stones with a cross-mark.
Reference sketches are then made to aid in understanding the topography of the area and guide surveyors while they run the survey line according to their plan.
Finally, the lines on the ground are established accurately by chain and compass to complete the surveying process.
How Many Meters Is A Survey Chain?
A survey chain, also known as Gunter’s chain, is still widely used for surveying in English-speaking countries. Invented by the English mathematician Edmund Gunter in the early 17th century, a survey chain is precisely 20 meters long and divided into 100 interlocking links.
This standard length of a survey chain was kept consistent from its invention up until modern times as an efficient measuring device to accurately survey land parcels.
What Are The Errors In Chain Surveying?
Chain surveying is an efficient and accurate method for taking measurements in land surveying.
However, due to certain factors like erroneous length of the chain or tape, inefficient ranging, straightening, careless holding and markings, sag in the chain, personal mistakes, and variation in pull or temperature can lead to certain errors while using this method.
To minimize such errors it is important to ensure proper maintenance and take accurate measurements with a properly calibrated instrument.
