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Chapter 4

Chapter 4. Measuring Sitework, Excavation, and Piling. Objectives. Upon completion of this chapter, you will be able to: Determine the likely soil conditions at a site by studying a soils report

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Chapter 4

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  1. Chapter 4 Measuring Sitework, Excavation, and Piling

  2. Objectives • Upon completion of this chapter, you will be able to: • Determine the likely soil conditions at a site by studying a soils report • Explain the use of swell factor and compaction factor when calculating volumes of excavation and backfill

  3. Objectives (cont’d.) • Define bank measure and explain how it applies to sitework takeoffs • Describe and use the “grid method” of calculating cut and fill volumes • Describe and use the “section method” of calculating cut and fill volumes • Explain how piling work is measured in a takeoff

  4. Objectives (cont’d.) • Explain how trenches and basements are measured in a takeoff • Complete a manual takeoff of sitework • Complete a computer takeoff of sitework using Excel spreadsheets and MC2 ICE software

  5. Generally • Measuring sitework and excavation work • Different from measuring most other work • Current site condition may not be provided • Dimensions and shape of excavations may not be disclosed • Estimators must assess requirements before measuring site work

  6. Soils Report • Provides subsurface condition information • Usually not a bid document • Includes data for foundation system design • Comments on sample soils report • Topsoil, moisture content, soil compaction, slope ratio, drainage, etc.

  7. Bank Measure, Swell, and Compaction Factors • Extracted soil • Less dense and will occupy more space • Compaction factor • Difference between hole volume and fill material volume • Bank measure • Obtained using hole dimensions

  8. Excavation Safety Considerations • Potential danger to workers • Cave-ins • OSHA’s Construction Safety and Health Regulations • Requires shoring systems or cutting back sides to a safe angle • Strongly enforced

  9. Use of Digitizers • Electronic devices • Enables user to take measurements from drawings • Input directly into computer program • Digitizer types • Sonic • Tablet

  10. On-Screen Takeoff • Eliminates need for paper-based printouts • Number of formats • Cost savings • Speed • Convenience • Plans still have to be drawn to scale

  11. Measuring Notes—Excavation and Backfill • Include: • Measure in cubic yards or cubic meters “bank measure” • Classify and measure separately • Excavations • Materials • Hand excavation • Disposal of surplus soil

  12. Calculation of Cut and Fill Using the “Grid Method” • Requires a site survey • Showing elevation of existing grade • Each intersection point on the grid • Plotted at each intersection point • Depth of cut can be obtained at each point • Refer to Figures 4.1 and 4.2 • Accuracy depends on grid spacing

  13. Calculation of Cut and Fill Using the Section Method” • Mostly used with long, relatively narrow areas of cut and fill • Road and railroad construction • Results quality depends on accuracy of plotting • Refer to Figure 4.3

  14. Trench Excavations • Formula for trench volume: • Trench Volume = Length of Trench Centerline ×Average Width of Trench ×Average Depth of Trench • Refer to Figure 4.4 • Sides of trenches often cut-back due to: • Safety reasons • Soil will not stand vertically

  15. Trench Backfill • Volume of backfill for a trench • Generally equal to volume of excavation minus volume of what is to be contained • Surplus occurs when volume of excavation exceeds amount required for backfill • Item for disposal of surplus material is required

  16. Greater Accuracy • Formula used to calculate volume of excavation: • Usually sufficient • Some situations require more accuracy • Example: pit and basement excavations

  17. Measuring Notes—Piling • Often subcontracted to specialized companies • Typical general contractor items: • Layout of piles • Cutting off tops of piles • Removing excavated material

  18. Bearing Piles • Generally: • Measure in linear feet or meters • Include a separate lump-sum item for equipment • Piles that are measures separately • Measurement may be subdivided • Enumerate splicing and lengthening of piles

  19. Bearing Piles (cont’d.) • Additional considerations: • Classification of bearing piles • Timber piles • Steel piles • Precast concrete piles • Poured-in-place concrete piles

  20. Sheet Piling • Generally: • Described and measured in square feet or square meters • Separately measure piles • Measurement may be subdivided • Measure withdrawing of piles • Cutting off of sheet piling: measured in linear feet or meters

  21. Sheet Piling (cont’d.) • Splices: described and measured by number • Timber sheet piling, concrete sheet piling, and steel sheet piling: measured according to foregoing principles • Extraction of piles: measured separately

  22. Additional Examples • Drawings • Refer to Figures 4.11 and 4.12 • Sitework takeoff • Example 1—The House Project • Takeoff Shown as Figure 4.6a • Example 2—The Office/Warehouse Project • Takeoff Shown in Figure 4.14a • Sitework Takeoff Using ICE Software

  23. Summary • The estimator has to make an assessment of sitework requirements • Based on plans and specifications • Site visit • Soils report • Efficiency can be increased using a digitizer • Sitework takeoffs can be done manually or via computer

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