ESTIMATING EARTHWORKProf Awad S. Hanna Estimating Earthwork Earthwork includes: 1. Excavation 2. Grading: Moving earth to change elevation 3. Temporary shoring 4. Back fill or fill: Adding earth to raise grade 5. Compaction: Increasing density 6. Disposal Prof Awad S. Hanna Hanna .Productivity Factors A. Job conditions Material type Water level and moisture content Job size Length of haul Haul road condition (accessibility and load restrictions) Prof Awad S. ) B. supervision and coordination of work.Productivity Factors (cont. Hanna . Prof Awad S. Management conditions Equipment conditions and maintenance practices Skills of work force and management Planning. 76 0.72 0.71 0.75 0.65 0.70 0.78 0.63 Good 0.61 Fair 0.65 0. Hanna .81 0.84 0.Job Efficiency Factors for Earthmoving Operations Management Condit ions* Job Condit ions** Excellent Good Fair Poor Excellent 0.57 Poor 0.52 Prof Awad S.60 0.69 0. Hanna . or compacted) Bank (BCY): Mat erials in it s nat ural st at e before dist urbance (in-place.Units of Measure Cubic Yard (bank. in-sit u) Loose (LCY): Mat erial t hat has been compact ed or dist urbed or loaded Compact ed (CCY): Mat erial aft er compact ion Prof Awad S. loose. 25 CUBIC YARD AFTER DIGGING (LOOSE YARDS) 0. Hanna .0 0.1.90 CUBIC YARD AFTER COMPACTED (COMPACTED YARDS) 1.25 1.90 In place Loose Compacted Prof Awad S.0 CUBIC YARD IN NATURAL CONDITION (IN-PLACE YARD) 1. Volume Bank: VB Bank cubic yards (BCY) Density B Lb /BCY Loose: Vl Loose cubic yards (LCY) Density L Lb/LCY Compacted: Vc Compacted cubic yards (CCY) Density C LB/CCY Prof Awad S. Hanna . Swell (%) = Bank density ( Loose density .Swell: A soil increase in volume when it is excavated.1) x 100 Load factor = Loose density Bank density Bank Volume = Loose volume x Load factor Prof Awad S. Hanna . Shrinkage: A soil decreases in volume when it is compacted Bank density Shrinkage (%) = (1 ) Compacted density x 100 Shrinkage factor = 1 . Hanna .Shrinkage Compacted volume = Bank volume x Shrinkage factor Prof Awad S. 400 2. dry Sand.1 00 2.91 Exact values will vary with grain size. dry Clay and gravel.520 1 3 0.89 3. dry Eart h. wet Sand and gravel. wet Gravel. wet Eart h.78 3. wet Gravel.88 3.1 00 2.700 2.Approximate Material Characteristics Mat erial Clay.400 Bank Swell Load (lb/cy) (% Fact or ) 2. wet Clay and gravel. Test to determine exact values for specific soils.85 2. dry Sand and gravel.900 3.1 00 1 7 0.620 1 7 0.090 2.85 2.600 3.250 1 2 0.850 29 0. wet Loose (lb/cy) 2. dry Sand.780 3. compaction. etc. dry Clay. Hanna .750 1 0 0.600 2.920 1 2 0. moist Eart h.750 2.79 3.85 3.78 3.21 5 2.76 2.800 1 7 0.650 26 0.81 3.1 40 1 3 0.41 0 2.575 32 0. moisture content. Prof Awad S.88 3.89 3.380 23 0.080 28 0. 00 12 .00 1 .87 15 .00 0.79 11 .Typical Soil Volume Conversion Factors Init ial Soil Type Soil Condit ion C lay Bank Loose C ompact ed C ommon eart h Bank Loose C ompact ed Rock (blast ed) Bank Loose C ompact ed Sand Bank Loose C ompact ed Bank 1 .1 1 .25 0.00 0.89 1 .00 0.00 0.50 1 .00 0.00 Prof Awad S.05 Convrt ed t o: Loose Compact ed 1 .67 0.1 0.41 1 .00 0.77 1 . Hanna .39 1 .1 1 .80 11 .72 1 .27 0.00 0.30 1 .71 1 .90 1 .85 18 .95 1 .00 0.1 1 .1 1 .90 1 .00 1 . Hanna Angle of Repose .Estimating Earth work for Trenches and Foundation 2’-0” or more Prof Awad S. Hanna .) Prof Awad S.Approximate Angle of Repose For Sloping Sides of Excavation Original Ground Line Solid Rock. Slate or Cemented Sand and Gravel (90 Deg. End Area Method 2.Calculating Earthwork Quantities 1.Contour Line/ Grid Method Prof Awad S. Hanna . 1. Hanna . End Area Method Used in sites where length is much greater than width Prof Awad S. CALCULATING EARTHWORK QUANTITIES 1. typically. Hanna . Calculate the cross-section end areas c. Take cross-sections at regular intervals. The volume of earthwork between sections is obtained by taking the average of the end areas at each station in square feet multiplied by the distance between sections in feet and dividing by 27 to obtain the volume in cubic yards. 100’ intervals. End Area Method a. b. Prof Awad S. Hanna 300' .Project Site Showing 100 A’ B’ C’ D’ Stations E’ F’ 80 82 84 86 88 A 100' B 100' C 100' 500' D 100' E 100' F Prof Awad S. 80 Sec. C’. F’.2 88 Prof Awad S. A’. E’.E 86. D’. Hanna .3 80 Project Cross Sections 78 84 Sec.D 84.A 78.F 88.B 80.2 84 88 Sec.5 78 76 82 Sec.C 82.2 86 90 Sec.3 82 80 86 Sec. B’. A Prof Awad S. Hanna .7 Area = 193 x 1.7 76 2 Section A’.0 2 = 53.8 77 = 173.A 80 Area = 107 x 1.Cross-Section @ A .5 78.5 78 76.5 79 79. B Prof Awad S.Cross-Section @ B .0 78 2 Section B’.B 82 Area = 90 x 1.3 80 76.8 79 = 189.8 = 67.5 2 81.7 Area = 210 x 1. Hanna .5 81 80. 41 8 .486 21 5 791 896 681 1 95 0 1 031 1 67 1 1 67 1 1 362 0 1 222 1 384 1 384 2746 Prof Awad S. (BCY) Exc. x B/C Net Exc.41 8 567 441 499 . Cumulative Earthwork Quantities Sect ion A-B B-C C-D D-E E-F Emb (CCY) Exc. Cum Exc (CCY) (CCY) (CCY) 672 224 254 .68 . Hanna .Table 1. 2. Contour Line/ Grid Method Used for parking lots and site “leveling” Grid size from 10’x10’ to 50’x50’ the greater the terrain variance the smaller the grid Prof Awad S. Hanna . Step 3 Determine elevations at each calculation location. Hanna . CONTOUR LINE/GRID CELL METHOD(cont. Step 5 Add the individual Grid Cell quantities together to arrive at the total cut. Prof Awad S.) Step l Determine by visual study of the site drawing if the net total will be an import (more fill required than cut) an export (less fill required than cut) or a blend (cut and fill about equal) Step 2 Determine the pattern of calculation points or grid size. the corners of each grid. total fill volume and the import or volume export yardage required for the job. Step 4 Calculate the cubic yards of cut or fill required in each grid cell.2. 0 93.0 A 87.5 95.4 H 88.4 D 90.3 G 87. 2.3 F 93’ 94’ G 92’ 91.7 93. Bring the entire site to elevation 90.5 C 90’ 89.6 C 89. 3.4 R 91.2 O 87.6 L 91.3 S 92.6 M 92.4 E 91.2 94.3 D 300’ E 91’ 90. Hanna . ft.A 88’ 87.6 B 89’ 88.6 F 93.2 J 89. All grids are 50’x 50’ = 2500 sq.5 K 90.5 N 87.6 B 88.1 No Scale Notes: 1.0 Q 90. Present contours Prof Awad S.7 P 89. 50 27 300' 90' 91' 90. Purpose Grade the entire site to grade 90’ 90' Need Fill Need Cut Quick and Dirty Assume one grid Existing 90. Hanna 150' .50 Proposed 90.5' 150 Total Cost = x 300 x 0.00 Cut 0.50 = 833CY Prof Awad S. 5+87. 87.6 4 = 88.If we choose the grid size to be 50’x50’ Average elevation = 87.6+88.6 87.6 Prof Awad S.6+88.77 CY and so on.92 cut = = 177.08 change = 90-88.6 88. Hanna .08 = 1.6 87.