Chapter 6 - Intro to Leveling

1. Chapter 6 - Intro to Leveling • Horizontal and Level Surfaces • Datums • Levels • Level Rods • Setting up the Level

2. Horizontal and Level Surfaces • Vertical lines • Follow gravity • Converge • Datum – reference at known distance from center of gravity • Elevation – vertical distance above datum • Level surface connects points of equal elevation • Horizontal is perpendicular to Vertical

3. Datum Elevations • Sea level • NGVD 1929 • NAVD 1988 • “Above flood stage” • Fargo – height over one of the dams • Harwood - NAVD • Assumed

4. Levels • Dumpy • Tilting • Automatic • Digital • Laser

5. Dumpy Levels

6. Reticle Cross-hairs Capstan’s screws Telescope Parts

7. Focusing – Parallax • Two focus adjustments • Objective • Eyepiece • Both must focus on the reticle • If not, image moves, or is out of focus • Focus eyepiece while sighting on a white piece of paper before sighting on target

8. Compensator Three-screw leveling foot Automatic Levels

9. Digital Levels • Automatic level • Level rod: barcode • Push button: • Rod Reading • Distance • Microprocessor • Set reference • Internal Calculations

10. Laser Levels • Low power • Types • Spinner • Splitter • Pipeline • Receiver • Indicates Hi/Low • Clamps to rod • Tied to Equipment

11. Level Rods Feet: larger numbers, red Feet: unknown 1/10ths: 0.1 1/100ths: .07 Read: X.17’ Tenths: black numbers Hundredths: black bar, 0.01’ thick. Tops: even, Bottoms: odd

12. Builder’s Rod,Read to 1/8” Engineer’s Rod,Read to 0.01’ Level Rods

13. Reading the Rod Fig. 6-11, pg 116

14. Setting up the Level • Tripod set firmly in ground • No plumb bob – point not needed • Level the level screws • Pairs across • Follow left thumb • Lock in place • Check Level