SURVEY AND GRADING. Surface drainage Especially from house Toward drain inlet.
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Transcript of SURVEY AND GRADING. Surface drainage Especially from house Toward drain inlet.
INSTRUMENTS OF SURVEYING
Builder’s level• Tripod mounted
“scope”• Leveled so view is
perfectly level in all directions
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
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’
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%