Tiêu đề NOTES BCEM (U-3).pdf ✅

RUNGTA COLLEGE OF ENGINEERING AND TECHNOLOGY, BHILAI Department of Civil Engineering 2 CIVIL DARSHAN a. Let A & B are control points, a new point C can be established. b. Following are the methods of locating point C from such reference points A & B. c. The distance AB can be measured accurately and the relative positions of the point can be then plotted on the sheet to some scale. d. Taking linear measurement from A and B for C. e. Taking linear measurement of perpendicular from D to C. f. Taking one linear measurement from B and one angular measurement as∕ ABC g. Taking two angular measurement at A & B as angles / CAB and / ABC. h. Taking one angle at B as / ABC and one linear measurement from A as AC. Diagram of Principle 1 Diagramof Principle 2
RUNGTA COLLEGE OF ENGINEERING AND TECHNOLOGY, BHILAI Department of Civil Engineering 3 CIVIL DARSHAN  Objectives of Surveying- 1. To determine the relative position of any objects or points of the earth. 2. To determine the distance and angle between different objects. 3. To prepare a map or plan to represent an area on a horizontal plan. 4. To develop methods through the knowledge of modern science and the technology and use them in the field. 5. To solve measurement problems in an optimal way.  Types of Surveying- 1. Surveying may be divided into two general categories- 1. Geodetic Surveying- Geodetic surveying is a particular type of surveying where the curvature of the earth is taken into account. 2. Plane Surveying- It is a specific type of surveying where the surface of the earth is considered as a plane and the curvature of the earth is not taken into account. 2. Classification based on the nature of the field- 1. Land Surveying. 2. Marine Surveying. 3. Astronomical Surveying. 3. Classification based on the object of the survey- 1. Archaeological survey. 2. Geological Survey. 3. Mine Survey. 4. Military Survey. 4. Classification based on the instruments – 1. Chain Surveying- Chain surveying is the simplest method of surveying in which linear measurements are directly taken in the field and angular measurements are not taken. 2. Plane Table Surveying- In plane table surveying, the fieldwork and plotting are done using a graphical method. It is mostly adapted for small and medium scale mapping where great accuracy is not required.
RUNGTA COLLEGE OF ENGINEERING AND TECHNOLOGY, BHILAI Department of Civil Engineering 4 CIVIL DARSHAN 3. Compass Surveying- In this type of surveying, a compass is used to determine the direction of survey lines, and the length of survey lines is measured by a chain or tape, or laser range finder. 4. Tacheometric Surveying- Tacheometric surveying is a method of surveying in which the horizontal and vertical distances of relative points are determined without using any sophisticated instruments such as chains, tape, etc. 5. Theodolite Surveying- The theodolite is an instrument that is used to measure horizontal and vertical angles. 6. Photographic and Aerial Surveying- These types of surveying are done by taking photographs from elevated ground stations. 5. Classification based on the methods of Survey- 1. Triangulation Surveying- Triangulation is a method of surveying that measures the angles in a triangle formed by three survey control points. 2. Traverse Surveying- It is also a well-known method of surveying. A traverse is a series of connected lines whose lengths and directions are measured with the help of an angle measuring instrument and tape or chain, respectively. LEVELLING-  Definition- The technique of determining the relative altitude of a point on the earth's surface below the earth's surface is called levelling.  Principle Of Levelling- The principle of levelling is to obtain a horizontal line of sight at which the vertical distance of a point above or below this line of sight is found.  The Purpose of Levelling- 1. Find the heights of the given points in relation to the given data. 2. Establishing points at given heights or at different heights in relation to given or considered data.  Technical Terms- 1. Station- Any points where the staff is held and the reading taken during the process of levelling is called stations. 2. Datum- It is an arbitrary level surface from which elevation of points may be referred. In India mean sea level is considered as datum of zero elevation, which is situated at Karachi.