© Awad S. Hanna, PhD, P.E.1 Estimating and Scheduling CEE 492 Lecture 5 ESTIMATING EARTHWORK

© Prof Awad S. Hanna2 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. Hanna3 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. Hanna4 Productivity Factors (cont.) B. Management conditions   Equipment conditions and maintenance practices   Skills of work force and management   Planning, supervision, and coordination of work. Ⓒ

© Prof Awad S. Hanna5 Table 1. Job Efficiency Factors for Earthmoving Operations Ⓒ

© Prof Awad S. Hanna6 Units of Measure Units of Measure   Cubic Yard (bank, loose, or compacted) Ⓒ

© Prof Awad S. Hanna CUBIC YARD IN NATURAL CONDITION (IN-PLACE YARD) 1.25 CUBIC YARD AFTER DIGGING (LOOSE YARDS) 0.90 CUBIC YARD AFTER COMPACTED (COMPACTE D YARDS) In place CompactedLoose Ⓒ

© Prof Awad S. Hanna8 Volume Bank: V B   Bank cubic yards (BCY)   Density B Lb /BCY Loose: V l   Loose cubic yards (LCY)   Density L Lb/LCY Compacted: V c   Compacted cubic yards (CCY)   Density C LB/CCY Ⓒ

© Prof Awad S. Hanna9 Swell: A soil increase in volume when it is excavated. Swell (%) = ( - 1) x 100 Load factor = Bank Volume = Loose volume x Load factor Loose density Bank density Loose density Ⓒ

© Prof Awad S. Hanna10 Shrinkage: A soil decreases in volume when it is compacted Shrinkage (%) = (1 - ) x 100 Shrinkage factor = 1 - Shrinkage Compacted volume = Bank volume x Shrinkage factor Bank density Compacted density Ⓒ

© Prof Awad S. Hanna11 Volume Example Clay Bank Density = 2650 B Lb/BCY Clay Loose Density = 2100 L Lb/LCY Clay Compacted Density = 2942 C Lb/CCY Swell (%) = [(2650/2100) - 1] x 100 = 26% Load Factor = (2100/2650) = 0.79 Shrinkage (%) = [1 – (2650/2942)] x 100 = 9.9% Shrinkage Factor = 1 – = 0.901

© Prof Awad S. Hanna12 Table 2. Approximate Material Characteristics   Exact values will vary with grain size, moisture content, compaction, etc. Test to determine exact values for specific soils. Ⓒ

© Prof Awad S. Hanna13 Table 3. Typical Soil Volume Conversion Factors Ⓒ

© Prof Awad S. Hanna14 Estimating Earthwork for Trenches and Foundation Angle of Repose 2’-0” or more Ⓒ

© Awad S. Hanna, PhD, P.E.15 Estimating Earthwork for Trenches and Foundation Ⓒ partments/public_work s/probid/pix/DSC00006.JPG

© Prof Awad S. Hanna16 Approximate Angle of Repose For Sloping Sides of Excavation Original Ground Line Solid Rock, Slate or Cemented Sand and Gravel (90 Deg.) Compacted Angular Gravels 1/2:1 (63 Deg.) Recommended Slope for Average Soils 1:1 (45 Deg.) Compacted Sharp Sand 1 1/2 :1 (33 Deg.) Well Rounded Loose Sand 2:1 (26 Deg.) Ⓒ

© Prof Awad S. Hanna17 Calculating Earthwork Quantities 1.End Area Method 2.Contour Line/ Grid Method Ⓒ

© Prof Awad S. Hanna18 1. End Area Method   Used for sites where length is much greater than width Ⓒ

© Prof Awad S. Hanna19 1. End Area Method a.Take cross-sections at regular intervals, typically, 100’ intervals. b.Calculate the cross-section end areas c.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. Ⓒ

© Prof Awad S. Hanna20 Project Site Showing 100 Stations Fill Cut A’ B’ C’ D’ E’’F’ AB C D E F 100' 500' 300' Ⓒ

© Prof Awad S. Hanna Sec. A’- A Sec. B’- B Sec. C’- C Sec. D’- D Sec. E’- E Sec. F’- F Project Cross Sections Ⓒ

© Prof Awad S. Hanna22 A - A Section A’- A Area == x Area == x Required Grade Cut Fill Existing Grade Ⓒ

© Prof Awad S. Hanna23 B - B Section B’- B Area == x Area == x Fill Cut Ⓒ

© Prof Awad S. Hanna24 Example of Cumulative Earthwork Quantities   Step 1: Calculate Average Volume of Fill Between Sections A-A and B-B (in CCY)   Ave. Area of Fill = SF SF = SF 2   Ave. Volume of Fill = SF x 100 LF = CCY 27 CF/CY This is Column 2 in Table 4

© Prof Awad S. Hanna 25 Example of Cumulative Earthwork Quantities   Step 2: Calculate Average Volume of Cut Between Sections A-A and B-B (in BCY)   Average Area of Cut = 53.5 SF SF = 61 SF 2   Average Volume of Cut = 61 SF x 100 LF = 224 CCY 27 CF/CY This is Column 3 in Table 4.

© Prof Awad S. Hanna26 Example of Cumulative Earthwork Quantities   Step 3: Convert BCY of Cut to CCY of Cut   From Table 3 (assuming common earth): To convert from Bank CY to Compacted CY, multiply BCY of Cut by 0.90 to get CCY of Cut material   CCY of Cut = 224 BCY x 0.90 CCY/BCY   CCY of Cut = 202 CCY This is Column 4 in Table 4.

© Prof Awad S. Hanna27 Example of Cumulative Earthwork Quantities   Step 4: Calculate Net Excess/ Deficit of Material   Subtract CCY of Cut from CCY of Fill to determine excess/deficit material.   Subtract Column 4 from Column 2 in Table 4 to arrive at Net Material (Column 5)   Step 5: Calculate Cumulative Excess/Deficit   Column 6 is the cumulative summation of material, which identifies an excess or deficit quantity of material.

© Prof Awad S. Hanna28 Example of Cumulative Earthwork Quantities Ⓒ Table 4. Cumulative Earthwork Quantities

© Prof Awad S. Hanna29 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. Hanna30 2. Contour Line / Grid Cell Method(cont.) 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. Step 3 Determine elevations at each calculation location, the corners of each grid. Step 4 Calculate the cubic yards of cut or fill required in each grid cell. Step 5 Add the individual Grid Cell quantities together to arrive at the total cut, total fill volume and the import or volume export yardage required for the job. Ⓒ

© Prof Awad S. Hanna31 A B C D E F G H J K L M N O P Q R S A B C D E FG 300’ 88’89’90’91’92’93’94’ No Scale Notes: 1. Bring the entire site to elevation All grids are 50’x 50’ = 2500 sq. ft. 3. Present contours Ⓒ

© Prof Awad S. Hanna32   Purpose Grade the entire site to grade 90’   Quick and Dirty Assume one grid Existing90.50 Proposed90.00 Cut 0.50 Total Cut == 833CY 150 x 300 x ' 150' Need Fill Need Cut 90' 91' 90.5' Ⓒ

© Prof Awad S. Hanna33   Average elevation = =   Change = = 1.92   Fill = CY and so on.  If we choose the grid size to be 50’x50’ Ⓒ