What is Chain Surveying (Principles, Procedure, Method, Instrument)

Among the different strategies for surveying, the usually utilized strategy is called chain surveying. For less exact works chain is utilized while, for progressively exact and exact work different kinds of surveys are utilized.

Standards of Chain Surveying: The rule of chain surveying is to give a skeleton structure of straight lines, which can be plotted to scale if the lengths of these lines are pre-decided either with a chain or a surveying tape.

The structure should generally comprise triangles. For instance, if all the four sides of the figure "ABCD" are known, the figure can't be plotted except if we know in any event the extent of one point.

Yet, on the off chance that we isolate the consideration along with two triangles by an inclining AC or BD whose length has recently been resolved, the plotting is conceivable because of the development of triangles of known sides. Or then again as such, if the lengths AB, BC, CD, DA, and BD are known, the quadrilateral ABCD can be plotted without knowing any edge.

BaseLine: The longest chain line in chain surveying is frequently called the BaseLine. It is the most Important line, repairs the headings of every single other line. Since the precision of the entire survey work relies on the exactness of the gauge, it ought to be laid off on the ground level however much as could reasonably be expected. Gauge should go through the focal point of the zone. It is estimated precisely, and all the fundamental redresses are applied.

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Rajib Dey
www.constructioncost.co
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Some important terminologies in surveying and leveling

Leveling stands for the method of finding out the relative elevations of several objects or points on the earth's surface. It is performed by picking up measurements in the vertical plane. A leveling instrument known as ?Level? and ?Staff? is appointed for this purpose along with other equipments.

Given below, some vital terms in Surveying and Leveling :-

Level Surface: It refers to a surface that is normal to the direction of gravity at all points as stated by a plumb line. As for instance, the surface of a still lake can be a level surface.

Since the earth is an oblique spheroid, a level surface should not belong to a plane but should be a cursed one. The distance of each point on a level surface is equal from the center of the earth.

Level Line: A level line belongs to a line that is laid on a level surface. It is normal to the plumb line at all points.

Horizontal Plane: A horizontal plane through a point refers to a plane peripheral to the level surface at the point. It is normal to the direction of gravity at that point.

Horizontal Line: A line that remains at a 90 degree angle to the plumb line and tangent to a level surface is called a horizontal line.

Vertical Plane: A vertical plane belongs to any plane with a vertical line. A vertical line at any point stands for a line normal to the level surface at that point.

A plumb line is an instance of a vertical line.

Datum Surface: A datum or datum surface is the level of a point or the surface relating to which levels of other points or planes are measured.

Elevation of a Point: Elevation of a point is the vertical distance above or below the datum. This is usually called the reduced level (R.L) of the point. This may be positive or negative accordingly as the point is above or below the datum.

Line of Collimation: The line of collimation or the line of sight stands for the line that connects the junction of cross-hairs to the optical center of the object glass and its continuation.

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Rajib Dey
www.constructioncost.co
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What is Plane Table Surveying

Plane Table Surveying is used in ad-hoc surveying and designing situations. In this, survey fieldwork and plotting work is done simultaneously. Therefore, there is no need for office work. This is best adapted to situations where high precision is not required. Thereby, it is greatly useful for small-scale mapping operations.

Instruments used in Plane Table Surveying - The Plane Table survey method uses very simple instruments. These are available everywhere.

1. Drawing Board: It is a board made of seasoned wood. They are available in many sizes. Generally, the field work is done in 40 cm by 30 cm boards. They also use the 75 cm by 60 cm boards, for larger work. In the field, a tripod is placed under the board with a ball socket in it. This enables the surveyor to draw on the board from any angle.

2. Alidade: An alidade is basically a ruler with a telescope. This is used on the drawing board to draw lines and rays according to the field. The alidade may also have a spirit level on it.

3. Compass: A tough compass is used to find the magnetic meridian of the place. Generally, the compass used in survey work also has two bubble tubes at right angles to each other.

4. Plumbing Fork: It is a rod with a plumbob attached to one end. This is used to ensure that other equipment is aligned perfectly vertically, when needed.

5. Spirit Level: It is a tube of liquid with a bubble inside it. The tube is slightly bulging in the middle. This lets the bubble stay in the middle of the tube when the level is perfectly horizontal. This is used to make sure the drawing board, or other equipment are placed horizontally.

6. Waterproof cover: A waterproof cover is used to cover up the paper on the drawing board from rain or other splashes and dust. This is generally made of soft polythene.

Read more

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Rajib Dey
www.constructioncost.co
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Some common types of symbols in surveying

In surveying, the objects or an area is demonstrated with symbols not by names. The civil engineer and land surveyor should have adequate knowledge on how to read the drawings, maps and plans.

In this exclusive civil engineering article, you will be familiar with various types of symbols applied land surveying.

These marks are arranged to mark key survey points on the Earth's surface.

Given below, some vital common signs and symbols found in the field of Surveying:

Surveyor flags and tape: Sometime the flags or streamers are just affixed to trees, fence posts, or provided on a stake so that they can be seen over the weeds. There should not be any markings on the stake, or only simple generic markings.

It signifies that this is the proper road and turn here. It could also signal a projected or estimated location for some future work.

Stakes with simple markings: Flags having some type of identification (it may belong to names or numbers). It is suitable for a projected well pad access road location. No dimensions are provided on these.

Stakes having simple flags and basic identification: All the stakes demonstrated here, point to an access route applicable for equipment and trucks to attain a projected pipeline right of way. The “H310″ stands for the EQT name for the 30” OVC pipeline.

Control points: These three stakes are used to recognize a control point that remains outside the limits of disturbance (LoD). These markings encircle a pin to be applied for reference.

Limit of disturbance: The “L O D” here signifies the limits of disturbance. Outside this point, no trees cut or dirt moved should exist. The stakes signifies that this is the outside limit of where the contractor will be unsettling the original contour of the surface soil.

Pipelines: Stakes with flags and “center line” markings are suitable for pipelines. Here, the symbol is demonstrated for center line: a capital letter “C” levied on the letter “L”.

Precise location markings: Stakes like this will normally contain a steel pin connected with it. This stake provides the latitude, longitude, and elevation of the site.

Permanent property lines: The markings can also be done with this one inch steel rod having an alum cap and it indicates permanent property lines and corners of property.

To get information on other types of symbols, go through this useful civil engineering video tutorial.


Video Source: Civil Engineer Deepak Kumar

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www.constructioncost.co
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CE CALC – An exclusive online calculator for Civil and Structural Engineers

CE Calc Civil Calculator refers to a useful construction tool for civil engineering calculation. It is specifically designed for the civil and structural engineering professionals so that they fulfill their design requirements. This exclusive calculator can be applied to accomplish calculations toward various cihydrology, open channels, culverts, gravity sewer, pressure pipe, transmission lines, traffic/road geometry, surveying/earthwork, pavement, concrete floors and unit conversions.

The calculator facilitates a civil engineer to discover latest design calculations rapidly and easily referencing the most updated codes and standards.

Given below, some striking features of CE CALC Civil Calculator

Hydrology:
Time of concentration and storm water runoff.

Open Channels:
Flow velocity, discharge, slope, weirs, Parshall flume and Froude Number.

Culverts:
Culvert selection and sizing, calculate headwater depth and outlet velocity.

Gravity Sewer:
Sanitary and storm sewer, velocity, discharge, slope head loss and pipe structural loads.

Transmission Lines:
Work out velocity head, minor losses, total dynamic head and pump properties.

Traffic/Road Geometry:
Passing distance, stopping distance, skidding distance, curve banking, horizontal curves, vertical curves and spiral curves.

Surveying/Earthwork:
Lattitudes and departures, azimuths, northings and eastings, area measurement, topographic leveling, earthwork volume and distance measurement.

Pavement:
Rigid and flexible pavement design by AASHTO and UFC design methods.

Concrete Floors:
Design of concrete floor slabs-on-grade using the UFC method.

Unit Conversion:
In-built unit conversion program, convert units of acceleration, angles, area, density, energy, flow, force, light, length, mass, power, pressure, temperature, torque, velocity and volume.

Click on the following link to download the calculator. 
Download Calculator

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Types of Engineering Surveying

Surveying is primarily categorized as below :

1. Plane surveying

2. Geodetic Surveying

Plane surveying refers to the survey in which the earth surface is considered as plane and the curvature of the earth is not taken into consideration. The plane surveys encompass only over lesser areas and the lines linking any two points on the surface of the earth are defined as straight lines and the angles among such lines are assumed as plane angles. To start with plane surveys, understanding of plane geometry and trigonometry is essential. In plane surveys, the covered are must be up to 260 km. In this regard, please remember that the variance in length among the arc and the subtended chord on the earth surface toward a distance of 18.2 km is only 0.1 m.

Geodetic Surveying refers to the particular type of surveying in which the shape of the earth should be considered primarily. All lines assigned in the surface are arc or curved lines and the angles belong to spherical angles. So, it contains spherical trigonometry. These measurements are applied for modifying curvature on maps and plans. Geodetic surveys also offer a wide array of control points over the Earth's surface which produce perfect plane surveys. All Geodetic surveys comprise work of larger magnitude and superior degree of accuracy. The motive of geodetic survey is to obtain the exact position on the surface of the earth. Geodetic surveys are initiated with extreme degree of precision to arrange broadly spaced control points on the earth surface for successive plane surveys.

Categorization of surveying

Surveys are also secondarily categorized with no. of headings which describe the applications or objectiveØÇ of resulting maps.

Categorization is done on the basis of type of field and there are three types of surveying :

1. Land Surveying: It is further divided as i) Topographical survey ii) Cadastrial Survey and iii) City Survey. It usually handles natural or artificial features on land like rivers, streams, lakes, wood, hills, roads, railways, canals, towns, water supply systems, buildings & properties etc.

2. Marine Surveying: Marine or hydrographic survey handles bodies of water for navigation, water supply, harbour works or for assessing mean sea level. The work comprises measurement of discharge of streams, arranging topographic survey of shores and banks, consiering and discovering soundings to ascertain the depth of water as well as observing the variations of the ocean tide.

3. Astronomical Surveying: The astronomical survey provides the surveyor means of ascertaining the absolute location of any point or the absolute location of and direction of any line on the surface of the earth. ‪

There are four types of surveying which are given below:

1. Geological Surveying

2. Mine Surveying

3. Archaeological surveying

4. Military surveying

Categorization on the basis of types of instruments applied: 

1. Chain surveying

2. Compass surveying

3. Plane table surveying

4. Theodolite surveying

5. Tacheometric surveying

6. Photographic surveying

Categorization on the basis of techniques used:

1. Triangulation surveying

2. Traverse surveying

Ref.: www.civileblog.com

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Published By

Rajib Dey

www.constructioncost.co

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