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Faculty of Applied Engineering and Urban Planning

Faculty of Applied Engineering and Urban Planning. Civil Engineering Department. Surveying. First Semester 2010/2011. Leveling Part 4 : Differential Leveling. Lecture 14 - Week 9. Content. Application of Leveling Contouring. Application of Leveling. Profiles Cross-sections Contouring

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Faculty of Applied Engineering and Urban Planning

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  1. Faculty of Applied Engineering and Urban Planning Civil Engineering Department Surveying First Semester 2010/2011 Leveling Part 4 : Differential Leveling Lecture 14 - Week 9

  2. Content • Application of Leveling • Contouring

  3. Application of Leveling • Profiles • Cross-sections • Contouring • Setting out levels

  4. Profiles (longitudinal sections) (center line of a railway, road, canal, sewer or water main) • Levels are taken at: • Every 20m, 50 or 100m depending on the topography • Points at which gradient changes • Street intersections • Staff reading to 0.01m accuracy are adequate. • Scale 1/1000 horizontal, and 1/100 vertical

  5. Profiles (longitudinal sections)

  6. Cross-Sections • Some Engineering works require that cross sections be taken at right angles to the center line of a proposed or existing project such as a road. • The width of these of sections are taken 15 m either side of the center for a normal road • Scale 1/50 or 1/100 for both horizontal and vertical axes.

  7. Cross-Sections

  8. Contouring A contour is an imaginary line connecting points on the ground that have the same elevation.

  9. Contouring • A contour interval the vertical distance or elevation difference between two successive contours • Depends on: • Scale • Purpose • Accuracy, time and cost • The topography • Area covered

  10. Characteristics of Contours 1- Closely contours represent a steep slope, but spaced far contours represent a flat slope. 2- Contours of different values do not cross each other except in a cave, nor do they merge except in a vertically standing surface such as a wall. 3- A single contour can not split into two contours of the same value, and must be a closed circuit not necessary in limits of the contour plan.

  11. Characteristics of Contours 4- Irregular contours represent a rough and uneven terrain. 5- contours are perpendicular to the direction of the steepest slope. 6- A hill or depression are represented by closed lines.

  12. Factors affecting choice of contour intervals 1- Contour plan scale: The larger scale is the smaller contour interval. 2- The importance and purpose of a contour plan : for more details, a small contour interval is used. 3- Accuracy, time and cost : For higher accuracy, a smaller interval is used. 4- The topography of the ground : For steep ground a large contour interval is used, but for flat ground a small contour interval is used. 5- The area covered by the plan: For larger areas, a large contour interval is used.

  13. Example 20 15 10 5

  14. Example 5 10 15 20

  15. Example 20 15 10 5

  16. Example 20 15 10 5

  17. Methods of Contouring Griding 3 1 2 4 5 A B C D

  18. Methods of Contouring Griding 1 cm 12 14 11 x 13 10 12 11

  19. Methods of Contouring Griding L x h2 h1 ho

  20. Methods of Contouring Griding 3 1 2 4 5 A 30 25 20 15 0 B 5 20 10 15 10 C 0 15 5 10 5 D 10 0 0 0 -5

  21. Questions?!

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