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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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28.2 28.4 28.6 28.8 29 29.2 29.4
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n(0
.01
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FWD
D0
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fle
ctio
n(µ
m)
Station (km)
Hwy 1-10
Round 1 Round 2 Round 3 Round 1 (BB) Round 2 (BB) Round 3 (BB)
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3.5 3.7 3.9 4.1 4.3 4.5 4.7
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FWD
D0
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fle
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n(µ
m)
Station (km)
Hwy 2-20 (Site B)
Round 1 Round 3 Round 1 (BB) Round 3 (BB)
THEEXTRAS•FWDshowsgoodrepeatability.Alsoappearsmoresensitivetolocalvariationsindeflection
•FWDseasonalvariationsclear…lesssowithBB
y = 0.1049x + 4.5451R² = 0.5008
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FWD Deflection (µm)
Hwy 2-20 (Site A)
Round 1 Round 3
THE RESULTS•Almost900datapoints•Point-by-pointcorrelationsarepoorwithinindividualsites
•Soilcementbase(onesite)hasdistinctivecharacteristicscomparedtogranularbase
Twoequationsweredevelopedbasedonbasetype:• ForSoilCement: BB=FWD*1.787+74.9• ForGranularBase: BB=FWD*1.131+19.2
