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NA2_A Inabnitt
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- 2. Dan InabnittDan Inabnitt KentuckyKentucky TransportationTransportation CabinetCabinet Divisionof PlanningDivision of Planning
- 3. Sensors •• Capacitance MatCapacitanceMat •• Rigid ChannelRigid Channel PiezoPiezo •• BareBare PiezoPiezo •• Bending PlateBending Plate •• Load CellLoad Cell
- 4. Capacitance MatCapacitance Mat ••Do wear out.Do wear out. •• Water destroys.Water destroys. •• Use permanent loops if possible.Use permanent loops if possible. •• Use TapUse Tap--Con screwsCon screws •• Lots ofLots of bitchethenebitchethene tapetape
- 5. Capacitance MatCapacitance Mat TypicalMat installationsTypical Mat installations
- 6. Rigid ChannelRigid ChannelPiezoPiezo •• Stay in concrete wellStay in concrete well •• Need good groutNeed good grout •• Tend to pop out of pavement especiallyTend to pop out of pavement especially rutted asphaltrutted asphalt •• Not easily “held” in slot during epoxyNot easily “held” in slot during epoxy cure timecure time
- 7. Rigid ChannelRigid ChannelPiezoPiezo ThisThis sensor hassensor has beenbeen workingworking for morefor more than sixthan six years!years!
- 8. Rigid ChannelRigid ChannelPiezoPiezo ThisThis sensorsensor hashas not.not.
- 9. Rigid ChannelRigid ChannelPiezoPiezo Too Deep?Too Deep? VoidVoid unevenuneven
- 10. Rigid ChannelRigid ChannelPiezoPiezo
- 11. BareBare PiezoPiezo •• EasilyinstalledEasily installed •• Installs quicklyInstalls quickly •• Small saw slotSmall saw slot •• Can be used in portable applicationsCan be used in portable applications
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- 13. BareBare PiezoPiezo Note voidNotevoid Note dipNote dip
- 14. Bending PlateBending Plate-- Load CellLoad Cell •• Have plenty of finishers available when usingHave plenty of finishers available when using ‘high‘high--early” concreteearly” concrete •• Don’t pour concrete directly on framesDon’t pour concrete directly on frames •• Pour sides and vibratePour sides and vibrate •• Tie rebar tightTie rebar tight •• Make sure water drains to the ditch and not toMake sure water drains to the ditch and not to the cabinet through conduitthe cabinet through conduit
- 15. Bending PlateBending Plate-- Load CellLoad Cell •• Always make sure you tamp the bottom of theAlways make sure you tamp the bottom of the pitpit •• Use joint sized epoxy coated rebarUse joint sized epoxy coated rebar •• Don’t bore under asphalt to concreteDon’t bore under asphalt to concrete •• Don’t expect a more expensive WIM systemsDon’t expect a more expensive WIM systems to compensate for poor road characteristicsto compensate for poor road characteristics
- 16. Bending PlateBending Plate TypicalBending Plate installationsTypical Bending Plate installations
- 17. Load CellLoad Cell TypicalLoadTypical Load--cell installationscell installations
- 18. Common to all ThreetypesThree types of installedof installed sensorssensors
- 19. Common to all TheGoodThe Good •• Work all the timeWork all the time •• Have worked for yearsHave worked for years •• Doesn’t matter what theDoesn’t matter what the installation looks likeinstallation looks like
- 20. Common to all TheBadThe Bad •• Don’t workDon’t work •• Can’t get it to workCan’t get it to work •• Doesn’t matter what theDoesn’t matter what the installation looks likeinstallation looks like
- 21. Common to all TheUglyThe Ugly •• Only works when you are thereOnly works when you are there •• Checks out OKChecks out OK •• The installation usually looks goodThe installation usually looks good
- 22. Common to all Investin aInvest in a good Digitalgood Digital StorageStorage OscilloscopeOscilloscope
- 23. Common to allCommonto all ContractorsContractors
- 24. Common to allCommonto all Roadway ConsiderationsRoadway Considerations •• StraightStraight •• SmoothSmooth •• LevelLevel •• “Good” surface“Good” surface •• No ruttingNo rutting •• ASTM WIM specASTM WIM spec
- 25. Common to allCommonto all RoadsRoads
- 26. Common to allCommonto all InstallationInstallation •• Have detailed plansHave detailed plans •• Have an “expert” on siteHave an “expert” on site •• Keep future repairs in mindKeep future repairs in mind
- 27. Common to allCommonto all Note allNote all leadlead--in slotsin slots converge toconverge to one point.one point. This makesThis makes futurefuture installationsinstallations and repairsand repairs difficult.difficult.
- 28. Common to allCommonto all Avoid wheel track “triangles”Avoid wheel track “triangles”
- 29. Common to allCommonto all
- 30. Common to allCommonto all DrillDrill oneone--inch holesinch holes in cornersin corners Run leadRun lead--in Straight to pull boxin Straight to pull box
- 31. Common to allCommonto all Don’t forget maintenance to otherDon’t forget maintenance to other components at site.components at site.
- 32. Common to allCommonto all Plan the workPlan the work •• Know where everythingKnow where everything is going to gois going to go •• Mark all saw cutsMark all saw cuts before starting the sawbefore starting the saw •• The more wires in a slot,The more wires in a slot, the deeper it has to bethe deeper it has to be
- 33. Common to allCommonto all Plan the workPlan the work •• Accurately measure/layoutAccurately measure/layout straight lines perpendicular tostraight lines perpendicular to traffic flowtraffic flow •• Cut accurate, straight slotsCut accurate, straight slots •• Always “wet” cutAlways “wet” cut
- 34. Common to all 3(9’)3 (9’) 4 (12’)4 (12’) 5 (15’)5 (15’) Don’t justDon’t just “eyeball it”.“eyeball it”. Measure it!Measure it! It can beIt can be easilyeasily accomplishedaccomplished byby constructingconstructing aa 33--44--55 triangle.triangle.
- 35. Common to allCommonto all Thoroughly clean all slots to remove anyThoroughly clean all slots to remove any debris, sludge, etc.debris, sludge, etc. Use high pressure washerUse high pressure washer Then dry with oil free compressed airThen dry with oil free compressed air Use wire brushUse wire brush
- 36. Common to allCommonto all SensorSensor crossingscrossings should beshould be 11--2mm2mm high,high, lightlylightly feathered.feathered. NO DIPSNO DIPS!!!!!! (Dip = Loss(Dip = Loss of Signal)of Signal)
- 37. Common to allCommonto all TheThe contractorcontractor didn’tdidn’t smile...smile... when hewhen he had tohad to replacereplace thisthis “smile”.“smile”.
- 38. Common to allCommonto all Loops were installed in base.Loops were installed in base.
- 39. Common to allCommonto all When driving surface was put down it did notWhen driving surface was put down it did not adhere to loop sealant. Neatness counts.adhere to loop sealant. Neatness counts.
- 40. Future DirectionsFuture Directions ••Fiber Optic sensorsFiber Optic sensors •• PiezoPiezo--quartzquartz •• ????
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