Comparative evaluation of fWD anD Benkelman Beam DefleCtions in saskatCheWan

THE PURPOSE•SMHIPhasedoutBenkelmanBeamTestingin2012•ReplacementwithFallingWeightDeflectometer•YearsofBenkelmanBeamdatacollected–wanttoutilize•DesiretohaveacorrelationbetweenFWDdeflectionandBenkelmanBeamDeflection

•Requirefieldinvestigationtodeterminecorrelation(s)

THE STUDY•EightsiteschosenbySMHI–7GBC,1soilcement

•Threeroundsofdeflectiontests:“Spring”“Summer”and“Fall”

•BenkelmanBeamTesting(SMHI)•FWD(EBA)

•GeotechnicalInvestigation(EBA)includingCoring

•SubgradeSampling/characterization

•RoadRadar™(groundpenetratingradar)Investigation

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Hwy 1-10

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Hwy 2-20 (Site B)

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THEEXTRAS•FWDshowsgoodrepeatability.Alsoappearsmoresensitivetolocalvariationsindeflection

•FWDseasonalvariationsclear…lesssowithBB

y = 0.1049x + 4.5451R² = 0.5008

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FWD Deflection (µm)

Hwy 2-20 (Site A)

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THE RESULTS•Almost900datapoints•Point-by-pointcorrelationsarepoorwithinindividualsites

•Soilcementbase(onesite)hasdistinctivecharacteristicscomparedtogranularbase

Twoequationsweredevelopedbasedonbasetype:• ForSoilCement: BB=FWD*1.787+74.9• ForGranularBase: BB=FWD*1.131+19.2