Chapter 4Measuring Sitework, Excavation, and Piling

ObjectivesUpon completion of this chapter, you will be able to:Determine the likely soil conditions at a site by studying a soils reportExplain the use of swell factor and compaction factor when calculating volumes of excavation and backfill

Objectives (contd.)Define bank measure and explain how it applies to sitework takeoffsDescribe and use the grid method of calculating cut and fill volumesDescribe and use the section method of calculating cut and fill volumesExplain how piling work is measured in a takeoff

Objectives (contd.)Explain how trenches and basements are measured in a takeoffComplete a manual takeoff of siteworkComplete a computer takeoff of sitework using Excel spreadsheets and MC2 ICE software

GenerallyMeasuring sitework and excavation work Different from measuring most other workCurrent site condition may not be providedDimensions and shape of excavations may not be disclosedEstimators must assess requirements before measuring site work

Soils ReportProvides subsurface condition informationUsually not a bid documentIncludes data for foundation system designComments on sample soils reportTopsoil, moisture content, soil compaction, slope ratio, drainage, etc.

Bank Measure, Swell, and Compaction FactorsExtracted soil Less dense and will occupy more spaceCompaction factorDifference between hole volume and fill material volumeBank measureObtained using hole dimensions

Excavation Safety ConsiderationsPotential danger to workersCave-insOSHAs Construction Safety and Health RegulationsRequires shoring systems or cutting back sides to a safe angleStrongly enforced

Use of DigitizersElectronic devices Enables user to take measurements from drawings Input directly into computer programDigitizer typesSonicTablet

On-Screen TakeoffEliminates need for paper-based printoutsNumber of formatsCost savingsSpeedConveniencePlans still have to be drawn to scale

Measuring NotesExcavation and BackfillInclude:Measure in cubic yards or cubic meters bank measureClassify and measure separatelyExcavationsMaterialsHand excavationDisposal of surplus soil

Calculation of Cut and Fill Using the Grid MethodRequires a site survey Showing elevation of existing gradeEach intersection point on the gridPlotted at each intersection pointDepth of cut can be obtained at each pointRefer to Figures 4.1 and 4.2 Accuracy depends on grid spacing

Calculation of Cut and Fill Using the Section MethodMostly used with long, relatively narrow areas of cut and fillRoad and railroad constructionResults quality depends on accuracy of plottingRefer to Figure 4.3

Trench ExcavationsFormula for trench volume:Trench Volume = Length of Trench Centerline Average Width of Trench Average Depth of TrenchRefer to Figure 4.4Sides of trenches often cut-back due to:Safety reasonsSoil will not stand vertically

Trench BackfillVolume 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 backfillItem for disposal of surplus material is required

Greater AccuracyFormula used to calculate volume of excavation:Usually sufficientSome situations require more accuracyExample: pit and basement excavations

Measuring NotesPilingOften subcontracted to specialized companiesTypical general contractor items:Layout of pilesCutting off tops of pilesRemoving excavated material

Bearing PilesGenerally:Measure in linear feet or metersInclude a separate lump-sum item for equipmentPiles that are measures separatelyMeasurement may be subdividedEnumerate splicing and lengthening of piles

Bearing Piles (contd.)Additional considerations:Classification of bearing pilesTimber pilesSteel pilesPrecast concrete pilesPoured-in-place concrete piles

Sheet PilingGenerally:Described and measured in square feet or square metersSeparately measure pilesMeasurement may be subdividedMeasure withdrawing of pilesCutting off of sheet piling: measured in linear feet or meters

Sheet Piling (contd.)Splices: described and measured by numberTimber sheet piling, concrete sheet piling, and steel sheet piling: measured according to foregoing principlesExtraction of piles: measured separately

Additional Examples DrawingsRefer to Figures 4.11 and 4.12Sitework takeoffExample 1The House ProjectTakeoff Shown as Figure 4.6aExample 2The Office/Warehouse ProjectTakeoff Shown in Figure 4.14aSitework Takeoff Using ICE Software

SummaryThe estimator has to make an assessment of sitework requirementsBased on plans and specificationsSite visit Soils reportEfficiency can be increased using a digitizerSitework takeoffs can be done manually or via computer