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Calculating Cut and Fill
Norman W. Garrick CE 4410 Spring Lecture 8
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Average End Area Method
Typically used for linear projects such as roads, railroads, canals
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Find area of Fill and Cut separately
for selected cross-sections Volume of Fill (or cut) between Two Cross-sections = [(A1 + A2)/2 ] * L Where: A1 is area of fill for Cross-section 1 A2 is area of fill for Cross-section 2 L is distance between 1 and 2
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A refinement to this approach is used
when A1 or A2 is an end cross-section (there is not fill or cut) In this case, (A1+A2)/2 * L Over estimates the volume since The shape of the earthwork is more Like a pyramid. In this case a more accurate formula Is [(A1+A2)/3] * L (Note there is an error in text for this formula)
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Contour Area Method Calculating Cut and Fill
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Determine the cut/fill line
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Find the area between the existing and finished contour for cut and fill separately
Contour Line Cut Area (sq. ft) Fill Area (sq. ft) 28 26 10000 24 15000 22 30000 20 35000 18 17500 16
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Calculate Cut and Fill Volumes
Contour Line Cut Area (sq. ft) Fill Area (sq. ft) 28 26 10000 24 15000 22 30000 20 35000 18 17500 16 V = A1*h/3 + (A1+A2)*h/2 + (A2+A3*h/2 +…. (An-1+An)*h/2 + An*h/3
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Calculate Cut and Fill Volumes
Contour Line Cut Area (sq. ft) Fill Area (sq. ft) 28 26 10000 24 15000 22 30000 20 35000 18 17500 16 Cut V = A1*h/3 + (A1+A2)*h/2 + (A2+A3*h/2 +…. (An-1+An)*h/2 + An*h/3 = 10000*2/3 +( )*2/2+( )*2/2*30000*2/3 = cu. Feet = 3600 cubic yard Cut V = A1*h/3 + (A1+A2)*h/2 + (A2+A3*h/2 +…. (An-1+An)*h/2 + An*h/3 = 35000*2/3 +( )*2/ *2/3 = cu. Feet = 3200 cubic yard
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Borrow Pit Method Calculating Cut and Fill
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Find amount of cut or fill needed to create a terrace at elevation 96 ft
Figure 4.5 Textbook
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Find amount of cut or fill needed to create a terrace at elevation 96 ft
No.1 No.2 No.3 No.4 Figure 4.5 Textbook
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Find amount of cut or fill needed to create a terrace at elevation 96 ft
Cell No. 1 Cut/Fill at each Corner B3 Cut 99.4 – 96.0 = 3.4 ft B4 Cut 98.4 – 96.0 = 2.4 ft C3 Cut 98.3 – 96.0 = 2.3 ft C4 Cut 97.8 – 96.0 = 1.8 ft Average Cut = ( )/4 = 9.9/4 = ft Amount of Cut Cell No. 1 = Average Cut * Area = 2.475*10,000 = 24,750 cu. ft = 24,750/27 = 917 cubic yard = 920 cubic yard No.1 No.2 No.3 No.4 Figure 4.5 Textbook
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Find amount of cut or fill needed to create a terrace at elevation 96 ft
Cell No. 2 Cut/Fill at each Corner B4 Cut 98.4 – 96.0 = 2.4 ft B5 Cut 97.1 – 96.0 = 1.1 ft C4 Cut 97.8 – 96.0 = 1.8 ft C5 Cut 96.7 – 96.0 = 0.7 ft Average Cut = ( )/4 = 6.0/4 = 1.5 ft Amount of Cut Cell No. 1 = Average Cut * Area = 1.5*10,000 = 15,000 cu. ft = 15,000/27 = 556 cubic yard = 560 cubic yard No.1 No.2 No.3 No.4 Figure 4.5 Textbook
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Find amount of cut or fill needed to create a terrace at elevation 96 ft
Cell No. 3 Cut/Fill at each Corner C3 Cut 98.3 – 96.0 = 2.3 ft C4 Cut 97.8 – 96.0 = 1.8 ft B3 Cut 96.7 – 96.0 = 0.7 ft B4 Cut 96.6 – 96.0 = 0.6 ft Average Cut = ( )/4 = 5.4/4 = 1.35 ft Amount of Cut Cell No. 3 = Average Cut * Area = 1.35*10,000 = 13,500 cu. ft = 13,500/27 = 500 cubic yard No.1 No.2 No.3 No.4 Figure 4.5 Textbook
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Find amount of cut or fill needed to create a terrace at elevation 96 ft
Cell No. 4 Cut/Fill at each Corner C4 Cut 97.8 – 96.0 = 1.8 ft C5 Cut 96.7 – 96.0 = 0.7 ft B4 Cut 96.6 – 96.0 = 0.6 ft B5 Cut 96.0 – 96.0 = 0.0 ft Average Cut = ( )/4 = 3.1/4 = 0.78 ft Amount of Cut Cell No. 1 = Average Cut * Area = 0.78*10,000 = 7,800 cu. ft = 7.800/27 = 289 cubic yard = 290 cubic yard No.1 No.2 No.3 No.4 Figure 4.5 Textbook
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Find amount of cut or fill needed to create a terrace at elevation 96 ft
Total Volume Cut Cell 1 – 920 cu. yd. Cell cu. yd. Cell 3 – 500 cu. yd. Cell cu. yd. = 2270 cubic yard No.1 No.2 No.3 No.4 Figure 4.5 Textbook
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A Calculation Short-cut
Find amount of cut or fill needed to create a terrace at elevation 96 ft A Calculation Short-cut Use V = (A/4)*(1*h1 + 2*h2 + 3*h3 + 4*h4) Where V – volume of cut or fill A – area of each cell h1 – sum of cuts (or fill) for all grid corners common to one grid h2 – sum of cuts (or fill) for all grid corners common to two grids h3 – sum of cuts (or fill) for all grid corners common to three grid h4 – sum of cuts (or fill) for all grid corners common to four grids No.1 No.2 No.3 No.4 Figure 4.5 Textbook
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A Calculation Short-cut
Find amount of cut or fill needed to create a terrace at elevation 96 ft A Calculation Short-cut V = (A/4)*(1*h1 + 2*h2 + 3*h3 + 4*h4) h1 = ( )+( ) )+( ) = = 5.2 No.1 No.2 No.3 No.4 Figure 4.5 Textbook
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A Calculation Short-cut
Find amount of cut or fill needed to create a terrace at elevation 96 ft A Calculation Short-cut V = (A/4)*(1*h1 + 2*h2 + 3*h3 + 4*h4) h2 = ( )+( ) )+( ) = = 6.0 No.1 No.2 No.3 No.4 Figure 4.5 Textbook
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A Calculation Short-cut
Find amount of cut or fill needed to create a terrace at elevation 96 ft A Calculation Short-cut V = (A/4)*(1*h1 + 2*h2 + 3*h3 + 4*h4) h3 = 0 No.1 No.2 No.3 No.4 Figure 4.5 Textbook
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A Calculation Short-cut
Find amount of cut or fill needed to create a terrace at elevation 96 ft A Calculation Short-cut V = (A/4)*(1*h1 + 2*h2 + 3*h3 + 4*h4) h4 = ( ) = 1.8 No.1 No.2 No.3 No.4 Figure 4.5 Textbook
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A Calculation Short-cut
Find amount of cut or fill needed to create a terrace at elevation 96 ft A Calculation Short-cut h1 = 5.2 h2 = 6.0 h3 = 0 h2 = 1.8 V = (A/4)*(1*h1 + 2*h2 + 3*h3 + 4*h4) = (10,000/4)*(1* * *0 + 4*1.8) = 2260 cubic yards No.1 No.2 No.3 No.4 Figure 4.5 Textbook
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Find amount of cut or fill needed to create a terrace at elevation 97 ft
We need to do separate calculations for cut and fill Cut h1 = h2 = h3 = 0 h2 = 0.8 V = (A/4)*(1*h1 + 2*h2 + 3*h3 + 4*h4) = 1000 cubic yards No.1 No.2 No.3 No.4 Fill h1 = h2 = h3 = 0 h2 = 0 V = (A/4)*(1*h1 + 2*h2 + 3*h3 + 4*h4) = 250 cubic yards Figure 4.5 Textbook
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