Measuring Sitework, Excavation, and Piling

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 (contd.)

• 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 (contd.)

• 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
• OSHAs 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 NotesExcavation 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 NotesPiling

• 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 (contd.)

• 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 (contd.)

• 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 1The House Project
• Takeoff Shown as Figure 4.6a
• Example 2The 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