Chapter 6 - Intro to Leveling

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

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

Datum Elevations Sea level

NGVD 1929 NAVD 1988

“Above flood stage” Fargo – height over one of the dams Harwood - NAVD

Assumed

Levels Dumpy Tilting Automatic Digital Laser

Dumpy Levels

Telescope Parts

ReticleCross-

hairsCapstan’s

screws

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

Automatic Levels

Three-screw leveling foot

Compensator

Digital Levels Automatic level Level rod: barcode Push button:

Rod Reading Distance

Microprocessor Set reference Internal

Calculations

Laser Levels Low power Types

Spinner Splitter Pipeline

Receiver Indicates Hi/Low Clamps to rod

Tied to Equipment

Level Rods

Feet: larger numbers, red

Tenths: black numbers

Hundredths: black bar, 0.01’ thick. Tops: even, Bottoms: odd

Feet: unknown

1/10ths: 0.1

1/100ths: .07

Read: X.17’

Level Rods

Engineer’s Rod,Read to 0.01’

Builder’s Rod,

Read to 1/8”

Reading the Rod

Fig. 6-11, pg 116

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