TOPO GRAPHY earth shape and earthwork

1. TOPOGRAPHYearth shape and earthwork Interpreting the topographic contour plan Slope analysis Grading grading for circulation /Apinya/KMUTTarc354slope analysis03

2. Topography map • Construction of a slope profile from a topographic contour map • Contour interval: the height between each contour line. • Cross section of that shape • X axis represents distance, Y axis represents level change /Apinya/KMUTTarc354slope analysis03

3. Topography map : Slope form • Slope profile shows landform • What is landform? /Apinya/KMUTTarc354slope analysis03

4. Erosion Convex slope Topography map :Slopeform /Apinya/KMUTTarc354slope analysis03

5. Topography map:contour characteristics 1. Same elevation on one contour line and same level change in between each contour line. (called contour interval) 2. Every contour closes on itself. 3. Asummit or depression indicated by the elevation at highest, lowest points. 4. Contour lines never cross. 5. Uniform sloping surface 6. Convex slope 7. Concave slope 8. Valleys 9. Steep slope 10. Relatively level. 11. Ridge /Apinya/KMUTTarc354slope analysis03

6. Topographic model • Models are good mediums to give the feeling of the earth form and study the natural drainage pattern /Apinya/KMUTTarc354slope analysis03

7. Drainage pattern • Natural drainage pattern : Water always flows in 90 degrees direction of contour line. Always check the topography of overall large scale drainage pattern besides the on-site topography to see how much water flow through the channel. /Apinya/KMUTTarc354slope analysis03

8. Mapping slope from Topography map • Grading formula • G=D/L or L=D/G or D=GL • Gradient percent = D/L*100 /Apinya/KMUTTarc354slope analysis03

9. Interpreting slope • Slope analysis of 20.8 acre site. Diagram shows the use of graduated scale for mapping slopes from a contour map. /Apinya/KMUTTarc354slope analysis03

10. Interpreting slope /Apinya/KMUTTarc354slope analysis03

11. Slope criteria Suitable & recommended slope for each use concerning mobility, possible cut-fill,maintenance and drainage ability. /Apinya/KMUTTarc354slope analysis03

12. Slope criteria • Angles ofreposefor various types of slope materials. (Angles are given in degrees.) • What is Angles ofrepose? • Maximumangle for earth material that it can be inclined, and it will fail if beyond. /Apinya/KMUTTarc354slope analysis03

13. Grading Grading : is the act of remodeling the land form. It is one of the most important items in site planning, landscape design and construction. Grading serves three main purposes: • 1.To create a level to put something on; for a house, car, sport play field, a hotel, etc. • 2. To create circulation ways; road way, loading ramp, handicapped ramp, bicycle track, etc. • 3. To create special effect and solve special problem ; make a mound to hide parking lot or reduce sound, prevent erosion and landslide, aesthetic or psychological purposes. /Apinya/KMUTTarc354slope analysis03

14. Gradingmaking an area level to put something on • By cutting only • the soil is stable • require less cost for foundation construction • be able to do very steep slope • cost to transport earth from the site /Apinya/KMUTTarc354slope analysis03

15. Gradingmaking an area level to put something on • By filling only • easier to make a very level elevation • good for low land, flood problem area. • Unstable earth, needs a compaction. • Cost of transporting earth into the site /Apinya/KMUTTarc354slope analysis03

16. Gradingmaking an area level to put something on • By the combination of cut and fill • balance earth in the site, no transportation cost. /Apinya/KMUTTarc354slope analysis03

17. Gradingmaking an area level to put something on • By the combination of cut and fill: plan of slab on sloping topography /Apinya/KMUTTarc354slope analysis03

18. Gradingmaking an arealevelto put something on • Designing a level plane onsteeplysloping site. Source: LANDSCAPE ARCHITECTURE, John Ormsbee Simands. /Apinya/KMUTTarc354slope analysis03

19. Gradingwhen not to grade Avoid grading on the following conditions • 1. Grading that results in radical loss of vegetation and topsoil • 2. Grading that interrupts the natural drainage • 3. Grading that results in aesthetic degradation • 4. Grading on difficult slopes (excess of 25%) • 5. Grading in environmental unique condition; floodplain, bogs, • 6. Grading in areas effected by natural disaster; mudslides or along earthquake fault lines /Apinya/KMUTTarc354slope analysis03

20. Grading for circulation • Circulation routes should be level as possible. • Two ways to travelupslope terrain • (maximum slope for local street is 8%) /Apinya/KMUTTarc354slope analysis03

21. Grading forcirculation • The normal grading method is something between the two extremes with roads or paths climbing and falling gentry so as to allow the quickest trip with the least effort. /Apinya/KMUTTarc354slope analysis03

22. Grading for circulation Circulation routes crossing level country are relatively easy to grade-- providing uniform surface and assuring the roadway drains properly. • A uniform surface means smoothing out the bumps by spacing contours evenly. • Draining the level road sometimes requires creating artificial high and low points for water flow direction. These can be shown graphically with contours, spot elevations, or sections. Section through road with CROWN /Apinya/KMUTTarc354slope analysis03 Road sloped from side to side

23. Grading for circulation • Shortest distance but results extensive cutting, • common design guide is to align the road centerline with or parallel to the contour lines with minimal grading /Apinya/KMUTTarc354slope analysis03

24. Grading for circulation • When grading by CUTting , begin with the lowest contour and work up, by filling, begin with the top contour and work down. • Contours are spaced according to the gradient of the proposed route typically expressed in percent. For 10% slope, one meter interval contours would be spaced 10 m. apart /Apinya/KMUTTarc354slope analysis03

25. Grading for circulation • The most common way if existing topography is NOT to steep. The procedure is to select the contour in the middle of the road and cut half the contour above, fill half of the contour below. /Apinya/KMUTTarc354slope analysis03

26. Grading for circulation • If cut/fill creates a steep bank, a heavy rainfall can induce mudslides and erosion. Alternatives to separate the road way (if it is wide enough) should be considered along with the use of retaining wall on the high side of the slope. /Apinya/KMUTTarc354slope analysis03

27. Grading for circulation • The road crosses a series of contour and causes a very steep bank since the road needs UNIFORM slope design criteria. The situation should then avoid or try to compromise the cut and fill along the centerline. /Apinya/KMUTTarc354slope analysis03

28. Grading for circulation • Road crosses drainage swale, the problem concerning the intersection between road and topographical depression, the use of BOX CULVERT or BRIDGE would be chosen depend on the length and depth of the swale and the image of the design. /Apinya/KMUTTarc354slope analysis03

29. Reference books • 1. Grade Easy, • 2. Site Planning : Environmental process and development P.129-171, R. Gene Brooks, Prentice Hall N.J. 07632 • 3. Site Planning p.83-106, Assoc.Professor Decha Boomkum, Lecture sheet , Chulalongkorn University, Thailand • 4. Time-Saver standards for Landscape Architecture, Chales W.Harris & Nicholas T.Dines /Apinya/KMUTTarc354slope analysis03