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Chapter 4 Measuring Sitework, Excavation, and Piling.

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Presentation on theme: "Chapter 4 Measuring Sitework, Excavation, and Piling."— Presentation transcript:

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 MC 2 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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