SURVEY AND GRADING

SURVEY AND GRADING

Surface drainage • Especially from house • Toward drain inlet

SURVEY AND GRADING

Design berms and slopes

INSTRUMENTS OF SURVEYING

Tape measure• >100’• Feet/inches or feet/tenths

INSTRUMENTS OF SURVEYING

Builder’s level• Tripod mounted

“scope”• Leveled so view is

perfectly level in all directions

INSTRUMENTS OF SURVEYING

Transit• A builder’s level that

also measures angles

INSTRUMENTS OF SURVEYING

Laser levels

INSTRUMENTS OF SURVEYING

Spinning laser beam and sensor

INSTRUMENTS OF SURVEYING

Surveryor’s rod, big “yard stick,” to estimate spot elevation

INSTRUMENTS OF SURVEYING

SURVEY AND GRADING

What is elevation?• Height above average sea level

SURVEY AND GRADING

Benchmark• Permanent reference point

• Manhole cover, curb, fire hydrant

SURVEY AND GRADING

SURVEY AND GRADING

Contour lines • Connect points of similar elevation• The closer together contour lines, the

steeper the slope• The farther apart, the “flatter” the slope

SURVEY AND GRADING

Contour lines

SURVEY AND GRADING

What’s elevation of X(a) and X(b)?

SURVEY AND GRADING

SURVEY AND GRADING

Contour lines based on spot elevations

SPOT ELEVATIONS

Backsite• Reading on benchmark (BM)

• BM has a known elevation• Backsite + Benchmark Elevation = Height of Instrument• 6.12’ + 100’ = 106.12’

106.12’

SPOT ELEVATIONS

Foresites

• Readings at unknown elevations• Height of Instrument – Foresite = Elevation

• 106.12’ – 3.98’ = 102.14’

106.12’

102.14’

SPOT ELEVATIONS

• Construction stake at spot elevation• Mark stake to indicate grade change

• +0.0 (increase ground level in inches)• -0.0 (decrease level)

Let’s say a construction plan proposes Foresite A to be 101.00’

The existing elevation was determined to be 102.14’.

Existing elevation – Proposed elevation = Grade Change 102.14’ – 101.00’ = 1.14’

+1.14’

GRADING

Rough grading uses stakes with proposed changes marked

GRADING

LASER LEVELING

• Tractor adjusts box leveler according to laser level

LASER LEVELING

DETERMING SLOPES (39)

• (V÷H) X 100 = % OF SLOPE • Vertical (V) distance between 2 points• Horizontal (H) distance

• V = 3.14’ – 1.21’ = 1.93’• H = 150’• (1.93’ ÷ 150’) x 100 = 1.29%

CREATING A SLOPE (%)

H X Desired Slope % = Change in Elevation

H = 120’Slope % = 3% (or 0.03)120’ x 0.03’ = 3.6’

Slope needs to drop a total of 3.6’ to be 3%

3.6’