NondestructiveNondestructive EvaluationEvaluation (NDE)(NDE) ofof Bridges,Bridges, FoundationsFoundations andand PavementsPavements QA,QA, ForensicForensic andand RehabilitationRehabilitation ConditionCondition AssessmentAssessment

Larry D. Olson, P.E. Olson Engineering, Inc. Olson Instruments, Inc. Wheat Ridge (Denver), Colorado USA Rutherford, New Jersey (metro New York City) San Francisco, California www.olsonengineering.com and www.olsoninstruments.com WhatWhat isis NondestructiveNondestructive EvaluationEvaluation (NDE)?(NDE)?

• Methods of evaluating the integrity of structures/infra-structures without destroying them • Use stress wave, electromagnetic wave, electrical properties, magnetic properties, thermal properties or nuclear properties and physics ReferencesReferences forfor NDENDE MethodsMethods • ACI 228.1R-03, “In-Place Methods to Estimate Strength,” American Concrete Institute Manual of Concrete Practice, Part 2

• ACI 228.1R-98, “Nondestructive Test Methods for Evaluation of Concrete in Structures,” American Concrete Institute Manual of Concrete Practice, Part 2

• ASCE 11-99 – Condition Assessment of Existing Buildings (visual, destructive, NDT and NDE methods for concrete, masonry, metal and wood structures – Mr. Olson is an ASCE Instructor in the ASCE short course) OlsonOlson EngineeringEngineering ConsultingConsulting ServicesServices

• NDE for Internal Condition Assessment of Structures and Infrastructure • Structural Health Condition Monitoring • Rehabilitation, Repair and Forensic Engineering • Geophysical Engineering • Vibration Engineering • Applied Research and Development OlsonOlson EngineeringEngineering BackgroundBackground

• 17 person firm in Denver and New York • Structural, Geotechnical, Geophysical, Electrical, Mechanical, and Mining Engineers • Specialist Consultant across US • International projects in Asia, N. America, S. America, Middle East and Europe • 1.8 million of US funded Applied Research • Patented Impact Echo Scanner System AppliedApplied ResearchResearch ProjectsProjects

• NCHRP 21-5 and 21-5(2) Determination of Unknown Bridge Depths for Scour Safety • FHWA Dynamic Substructure Evaluation for Scour and Evaluations • NSF SBIR for SASW in Arctic Regions • NSF SBIR for Ultrasonic Tomographic Concrete Imaging • NSF SBIR for Nondestructive Concrete Strength • US BUREC for Prestressed Concrete Cylinder Pipe Impact Echo Scanning for Corrosion Delaminations • USDA SBIR for NDE of Wood with Scanning Technologies • Consultant to UT Austin, Univ. of Florida, U. of Maryland • Texas Tech University on Nails for TxDOT currently • NCHRP IDEA Program Award for Stress Wave Scanning for Grout/Void Evaluation of Post-Tensioned Ducts in Bridges WhyWhy NDENDE toto DiagnoseDiagnose Structures?Structures?

• Safety is significantly increased by knowledge of internal conditions with NDE for new to aging structures • NDE methods can investigate large structures and infrastructure economically to provide comprehensive information on internal conditions • NDE causes no damage to the structure and minimizes the need for destructive coring/testing NDTNDT ofof StructuresStructures andand PavementsPavements

• Impact Echo (IE) and Scanning • Slab Impulse Response – Locate voids, cracks or – Locate area of delamination honeycomb – Determine soil condition for – Measure thickness slab on • Ground Penetrating Radar • Ultrasonic Pulse Velocity – Locate rebar – Locate voids or honeycomb – Measure thickness – 2 sided access • Spectral Analysis of Surface Waves – Ultrasonic Tomography to Image flaws – Determine pavement system profiles and structural integrity • Half Cell and Galvapulse Corrosion Surveys NDTNDT ofof DeepDeep FoundationsFoundations

• Down-hole Method • Surface Method – Integrity Methods – Integrity and Length • Crosshole Sonic Logging (CSL) Method • Singlehole Sonic Logging (SSL) • Sonic Echo (SE) • Gamma-Gamma Density Method • Impulse Response (IR) • Crosshole Tomography (CT) • Ultraseismic – Length Methods • Impedance Image • Parallel Seismic (PS) • Induction Field • Radar GeophysicalGeophysical MethodsMethods

• Spectral Analysis of Surface Waves • Surface and Borehole Ground Penetrating Radar • Crosshole/Downhole Seismic Tests • Crosshole and Downhole Seismic Tomography • Seismic Refraction/Reflection Surveys • Electrical Resisitivity Surveys OlsonOlson InstrumentsInstruments SystemsSystems

• Freedom Data PC Family of Instruments for – Structural, Foundation, Pavement/Slab//Pipe, Geophysical and Vibration Engineering Applications

• Concrete Thickness Gauge CTG-1 for Thickness and Flaw Detection – Models CTG-1T and CTG-1TF

• Freedom DAS Data Acquisition System for - strain gages, thermocouples, potentiometers, vibration transducers, etc. FreedomFreedom DataData PCPC NDT&ENDT&E SystemsSystems andand FreedomFreedom DASDAS PCPC forfor StructuralStructural TestingTesting ConcreteConcrete ThicknessThickness GaugeGauge onon HighwayHighway PavementPavement TypicalTypical ConcreteConcrete ThicknessThickness GaugeGauge DisplayDisplay NDENDE MethodsMethods forfor StructuresStructures (and(and Pavements)Pavements)

• Acoustic Sounding/Chain Drag • Spectral Analysis of Surface Waves – Delamination mapping for corrosion – Determine structural integrity – predict concrete strength with core correlation • Ultrasonic Pulse Velocity – pavement system stiffness profiles – Locate voids or honeycomb – Predict concrete strength with core correlation • Slab Impulse Response – Locate areas of structural flaws • Ultrasonic Tomography – Determine soil support condition for pavements and slabs-on-grade – Image internal flaws

• Half Cell and Galvapulse – corrosion • Impact Echo (IE) and Scanning – Locate voids, cracks, honeycomb • Radar/Cover Meter – locate/size steel – Measure thickness AcousticAcoustic SoundingSounding forfor DeckDeck andand GirderGirder CorrosionCorrosion InducedInduced DelaminationDelamination MappingMapping

• Acoustic Sounding Methods – Chain Drag with Multiple Chains and Loops – Delam 2000 with Rolling Gear Sprockets – Hammers and Rods – Chains and Impact Devices with Microphones • ASTM D4580-02, “Standard Practice for Measuring Delaminations in Concrete Bridge Decks by Sounding” • Delaminations sound hollow, dull and drummy vs ringing, high frequency sound for good concrete LoopedLooped ChainChain DraggingDragging onon VAVA BridgeBridge DeckDeck FreedomFreedom DataData PCPC –– ImpactImpact EchoEcho ScannerScanner SystemSystem • Model: – IES-1: rolling IE scanner test head and cable – Test every 1 inch or 25 mm – Display internal concrete conditions in 2-D and 3-D of post-tensioned bridges – Microphone option for acoustic scanning for delaminations ImpactImpact EchoEcho (IE)(IE) ScannerScanner withwith MicrophoneMicrophone onon VAVA DeckDeck

IE Scanner mapping of delaminations with IE Scanner Solenoid, Microphone and solenoid impactor and microphone Rolling Displacement Transducer MappingMapping ofof ChainChain DragDrag andand MicrophoneMicrophone ResultsResults -- GoodGood correlationcorrelation butbut microphonemicrophone detaildetail betterbetter MultipleMultiple ChainChain DraggingDragging DeviceDevice onon ParkingParking DeckDeck DelamDelam 20002000 forfor OverheadOverhead UndersideUnderside ofof DeckDeck SoundingsSoundings DelamDelam 20002000 withwith RollingRolling GearGear SprocketsSprockets AcousticAcoustic Sounding/ChainSounding/Chain DraggingDragging Training,Training, AdvantagesAdvantages andand DisadvantagesDisadvantages

• Low Cost, Quickly Trained, Widely Used

• Accurate for shallow delaminations less than 3-4”

• Subject to operator experience when ear alone but more accurate when chain drag/impact source and microphone used UPVUPV TestTest GeometriesGeometries andand StrengthStrength CorrelationCorrelation

• Direct Transmission

• ACI 228.1 R - Velocity to the 4th power is proportional to Concrete Strength

• Semi-Direct Transmission

• Indirect Surface)Transmission Ultrasonic/SonicUltrasonic/Sonic PulsePulse VelocityVelocity (UPV/SPV)(UPV/SPV) forfor ConcreteConcrete IntegrityIntegrity andand StrengthStrength PredictionPrediction

• Measures speed of sound through concrete • Two Accessible Sides required for interior tests • ASTM Standard C597-97 for UPV Testing • Measurement of Arrival time and Signal Amplitude

• VP = Compression Wave Velocity = Distance/Time • Sonic Pulse Velocity (SPV) tests for mass concrete • Faster velocities = sounder concrete = stronger concrete ConcreteConcrete VelocityVelocity andand QualityQuality RelationshipRelationship

General Condition Pulse Velocity (feet/second)

Excellent Above 15,000 Good 12,000 – 15,000 Questionable 10,000 – 12,000 Poor 7,000 – 10,000 Very Poor Below 7,000

(After Leslie and Cheeseman, 1949) UltrasonicUltrasonic PulsePulse VelocityVelocity TestsTests forfor StrengthStrength PredictionPrediction onon FoamedFoamed ConcreteConcrete EmbankmentEmbankment TestTest CylindersCylinders CompressiveCompressive StrengthStrength LinearLinear CorrelationCorrelation withwith VelocityVelocity forfor FoamedFoamed ConcreteConcrete HighwayHighway EmbankmentEmbankment CylindersCylinders

Velocity vs Strength

350.00

300.00 y = 0.1799x - 968.4 R 2 = 0.9271

250.00

200.00 (psi)

150.00 Strength

100.00

50.00

0.00 5800 6000 6200 6400 6600 6800 700 UPV (ft/s)

Data Set Linear (Data Set) UPVUPV forfor QAQA ofof EpoxyEpoxy InjectionInjection RepairsRepairs toto BridgeBridge PierPier BeamBeam CracksCracks

54 kiloHertz lithium grease- coupled transducers in semi- direct test UPV Tests for Void/Honeycomb in Pier Segment of Segmental Bridge & Crushed or Cracked Concrete UPVUPV RecordsRecords forfor TestingTesting AcrossAcross CracksCracks andand QAQA ResultsResults ofof EpoxyEpoxy InjectionInjection RepairsRepairs UltrasonicUltrasonic PulsePulse VelocityVelocity forfor InvestigationInvestigation ofof Honeycomb/VoidHoneycomb/Void inin ConcreteConcrete HighwayHighway SignSign ColumnColumn UPVUPV TestTest GridGrid andand PCPC--BasedBased DataData RecordingRecording onon BridgeBridge SignSign ColumnColumn

54 kHz UPV transducers with 1 ft grid direct test patterns from North-South and East-West

UPV test data recorded for pulse velocity arrival time analyses on Freedom NDT PC SoundSound ConcreteConcrete withwith GoodGood SignalSignal atat 372372 usus andand PulsePulse VelocityVelocity ofof 13,50013,500 ft/sft/s Honeycomb/VoidHoneycomb/Void ConcreteConcrete withwith WeakWeak SignalSignal atat 552552 usus andand PulsePulse VelocityVelocity ofof 9,1009,100 ft/sft/s UltrasonicUltrasonic PulsePulse VelocityVelocity Training,Training, AdvantagesAdvantages andand DisadvantagesDisadvantages

• Commercial Equipment available, lab use training easy, field use training moderate difficulty for flaw testing and requires data recording

• Identifies Internal Flaws, but no information on depth

• Strength prediction with correlation with core results

• Requires 2-sided access which is many times difficult UltrasonicUltrasonic TomographyTomography forfor 22--DD CrossCross--SectionalSectional HorizontalHorizontal ImagesImages ofof InternalInternal Void/HoneycombVoid/Honeycomb ConditionsConditions inin HighwayHighway SignSign ColumnColumn

• 2-D Velocity Tomogram of Velocity in kfps 14.5 Column showing slow North 14 13.5 velocity zones indicative of 5 internal poor quality concrete 13 due to poor consolidation in 12.5 4 Void/Poor a horizontal slice and good 12 11.5 concrete 3 11 10.5 2 • UPV data from 5 N-S and 5 Good 10 E-W tests on a 1 ft grid was 9.5 1 used for this tomogram – 9 angled rays and more tests 8.5 0 produce more accurate 012345 8 images Distance in ft 7.5 7 UltrasonicUltrasonic TomographyTomography Training,Training, AdvantagesAdvantages andand DisadvantagesDisadvantages • Requires extensive training and experience for analysis, but field data collection less complicated

• Image internal flaws in 2-D and now 3-D fashion with angled and direct tests

• A picture is worth a thousand words sometimes and velocity tomograms provide an image of internal void, cracking and honeycomb

• Requires a lot of 2-sided UPV testing and more detailed analysis to obtain clear images ImpactImpact EchoEcho forfor ThicknessThickness andand InternalInternal FlawFlaw DetectionDetection withwith 11--SidedSided AccessAccess

• Reflection Test for Concrete and Masonry based on Sound Wave Echoes (technically resonance) • Determine Thickness of Members with One Accessible Side • ASTM Standard C1383-98 for Thickness Determination • ACI 228.2R-98 details detection of Void, Honeycomb, Cracking, Shallow to Deep Delaminations, etc. BackgroundBackground ofof ImpactImpact EchoEcho (IE)(IE)

• The IE test relies on Olson Instruments, Inc. Impact Echo IE-1 test head incorporating source and receiver reflection of compression waves from the bottom of the structural member or from any hidden discontinuity

• The selection of a hammer versus a smaller impactor Flaw depends on the thickness of the member so that appropriate frequencies Reflection from concrete/flaw * Reflection from backside of are generated. interface test member *Reflection from backside occurs at a lower frequency than that from the shallower concrete/flaw interface ApplicationsApplications ofof ImpactImpact EchoEcho

• Detect internal voids, honeycomb, cracks, delamination in concrete, wood and stone

• Measure thickness of slabs and pavements

• One sided access for testing is fast and convenient ApplicationsApplications ofof ImpactImpact EchoEcho onon PipesPipes andand TunnelsTunnels forfor WallWall Thickness/IntegrityThickness/Integrity

• Automated Solenoid Impactor for Rapid testing • Test Range of 3 to 24 inches deep in concrete • Small hammer to test out to 6 ft ConcreteConcrete ThicknessThickness GaugeGauge forfor QAQA ofof ThicknessThickness ofof HighwayHighway PavementsPavements

• CALTRANS Study on Pavement found 0.16 inch thick CTG-1TF accuracy on 8 inch thick pavment (Maser et al, 2003) TypicalTypical ConcreteConcrete ThicknessThickness GaugeGauge DisplayDisplay

• Resonant thickness echo peak at 5.78 inches for a 6 inch thick concrete pavement • Easy to use push- button Gauge for field technicians • High quality data saved for engineer analysis ImpactImpact EchoEcho TestTest

D = βVp/(2*f) D = Thickness/Echo Vp = Compressional Wave Velocity f = Frequency β = Shape Factor ImpactImpact EchoEcho TestTest PrinciplePrinciple andand EchoEcho DepthDepth CalculationCalculation • Record Response of Member to an Impact • Transform Data to the Frequency Domain • Identify Frequency Peak of Echo, f • Calculate Thickness or Depth (D) of an echo as:

• D = (β * VP)/2f, • β is shape factor which is 0.96 for slab/wall shapes and is less for beams and columns depending on their aspect ratio (depth to width)

• VP is Compressional Wave Velocity ImpactImpact EchoEcho AnalysisAnalysis –– TimeTime vs.vs. FrequencyFrequency

• Data are more apparent in frequency domain and are plotted vs. frequency here or depth as desired (CTG-1TF) and shown here for 1 ft thick Post-tensioned Segmental Bridge Wall Time Domain Data • D = βVp/(2*f) D = 0.96 (12,000 ft/s)/(2 x 5900 Hz) = 0.98 ft thick echo where D = Thickness Vp = Compresional Velocity f = Frequency Peak β = 0.96 for a slab/wall shape and is smaller for beam and column shape factors Frequency Domain Data GooseGoose CreekCreek BridgeBridge Evaluation,Evaluation, JeffersonJefferson County,County, ColoradoColorado

• Guardrail Post Load Tests • Corrosion Check with Galvapulse on reinforcing • Impact Echo Thickness/Integrity Tests – CTG & IE Scanner • Surface Wave Velocity Test • Acoustic Delam 2000 Deck Sounding • Ground Penetrating Radar and Cover Meter tests for reinforcing location/size • Core tests for strength/density of concrete GooseGoose CreekCreek BridgeBridge –– ConstructedConstructed 19621962 TwinTwin--TeeTee GirdersGirders GuardrailGuardrail PostPost ImpactImpact DamageDamage AcousticAcoustic DelamDelam 20002000 DeckDeck SoundingSounding ImpactImpact EchoEcho Thickness/IntegrityThickness/Integrity TestsTests –– ConcreteConcrete ThicknessThickness GaugeGauge CTGCTG--1TF1TF ImpactImpact EchoEcho RecordsRecords forfor DeckDeck andand TwinTwin--TT GirderGirder WebWeb

Impact Echo record from a twin-T bridge deck showing a thickness of 8.91 inches

Impact Echo record from the web section of a twin-T bridge showing a too large thickness of 10.6 inches (due to internal cracking) and a possible crack echo at 2.7 inches ImpactImpact EchoEcho Training,Training, AdvantagesAdvantages andand DisadvantagesDisadvantages

• Commercial Equipment available and Pushbutton to Windows Moderate Difficulty for use

• Identifies Thickness of Decks, Slabs and Pavements with good accuracy, limited training and easy analysis with 1- sided access

• Identifies Internal Flaws such as Void, Cracking, Honeycomb with Training and Experience

• Will not penetrate open cracks and voids ProblemProblem StatementStatement

• More than 130,000 post- tensioned bridges that contain steel tendons • If ducts are not fully grouted, water can enter the steel tendons resulting in corrosion of tendons

Poorly Grouted Duct – Tendons Exposed (from Videoscope) SunshineSunshine SkywaySkyway BridgeBridge –– TampaTampa Bay,Bay, FLFL

Pictures from Mr. Teddy Theryo of Parsons Brinckerhoff ImpactImpact EchoEcho ScanningScanning forfor InternalInternal GroutGrout ConditionCondition ofof PTPT Ducts,Ducts, Decks,Decks, otherother StructuralStructural ConcreteConcrete andand PavementsPavements

• Research with University of Florida at Gainesville for the Florida DOT • Locate voids in the post- tensioning plastic or steel ducts

Freedom Data PC with Impact Echo Scanner IEIE ScanningScanning ResultsResults fromfrom alongalong SteelSteel DuctsDucts atat UniversityUniversity ofof FloridaFlorida

6500 Hz Fully Grouted Duct

Empty Duct

5833 Hz

Cap with grout ImpactImpact EchoEcho PrinciplePrinciple

• Record Response of Member to an Impact • Transform Data to the Frequency Domain • Identify Frequency Peak of Echo, f • Calculate Thickness as:

• T = (β * VP)/2f, • β is shape factor equal to 0.96 for wall/slab

• VP is Compressional Wave Velocity ImpactImpact EchoEcho EquipmentEquipment PCPC--BasedBased oror ConcreteConcrete ThicknessThickness GaugeGauge byby OlsonOlson Instruments,Instruments, Inc.Inc.

• Handheld Solenoid Operated Impactor with built-in Displacement Transducer • 0.2 lb Impulse Hammer and Accelerometer • Point by Point Testing normally • In Smooth Areas such as Floors and Walls, IE Scanning is possible for near-continuous coverage Olson Instruments, Inc. Impact Echo IE-1 test head incorporating source and receiver

Flaw

Reflection from concrete/flaw * Reflection from ba ckside of interface test member *Reflection from backside occurs at a lower frequency than that from the shallower concrete/flaw interface ImpactImpact EchoEcho ScannerScanner (IES)(IES) –– USUS patentedpatented

• Add wheels to the unit • Add a rolling transducer and solenoid impactor • Calibrated to test every 25 mm or 1” interval • Speed = 4 meters (13 ft) in 1 minute for 160 tests/minute IESIES TestsTests onon aa CableCable StayedStayed PostPost-- TensionedTensioned BridgeBridge –– BiBigg DiDigg ProProjjectect CharlesCharles RiverRiver CrossinCrossingg inin Boston,Boston, MassachusettMassachusettss

GroundGround PenetratingPenetrating RadarRadar (GPR)(GPR) toto LocateLocate DuctsDucts

• 1.5 GigaHertz Antenna • Ducts were located precisely • Permitted borescope visual inspection • Vacuum Grouting Repairs Impact Echo Scanning along duct to check for void vs. grouted duct conditions

WallWall DimensionsDimensions (with(with 44 PostPost--TensionedTensioned Ducts)Ducts)

14’

Center Line of Duct A

Center Line of Duct B 8’ Center Line of Duct C

Center Line of Duct D

Vertical Scan Across Ducts IE Scanner Vertical Scan Across PT Ducts

Appears to have two zones of ungrouted ducts shown by thicker echoes than the normal wall, at 2-2.3 feet from the start of the scan, and at 3.2-3.4 feet. Apparent honeycomb/voids present at 3.5 to the end of the scan at 4.5 feet (scanning from bottom to top). ImpactechogramImpactechogram showingshowing highhigh amplitudeamplitude echoecho frequenciesfrequencies mirroringmirroring IEIE ScScanneranner ThicknessThickness EchoEcho DisplayDisplay

O kHz 2O kHz IESIES TestTest ResultsResults fromfrom aa CableCable StayedStayed PostPost--tensionedtensioned BridgeBridge

Blind Interpretation of IES results from 4 Ducts

Empty Duct Empty Duct Fully Grouted Duct Grouted with water

Actual Conditions inside 4 ducts (from Videoscope) ImpactImpact EchoEcho ScanningScanning Training,Training, AdvantagesAdvantages andand DisadvantagesDisadvantages

• Near-continuous scanning with tests every inch at testing rates corresponding to slow walking speeds

• Identifies Thickness of Decks, Slabs and Pavements with good accuracy with 1-sided access

• 2-D and 3-D Imaging of internal flaws such as cracking, void, honeycomb and grouted vs. ungrouted post-tensioning ducts

• Requires specialized equipment, training and experience

• Will not penetrate open cracks and voids NationalNational CooperativeCooperative HighwayHighway ReResearchsearch ProgramProgram InnovationsInnovations DeservingDeserving ExploratoryExploratory AnalysisAnalysis ResearchResearch ProjectProject InterimInterim ResultsResults -- MockMock--upup SpecimenSpecimen

• Full scale Pre-cast Bridge Girder for Curved, Post- Tensioned Interstate Bridge • 100 ft in length with 8 empty steel ducts (4 inches in diameter) • Typical wall thickness of the web is 10 inches SimulationSimulation ofof DefectsDefects insideinside SteelSteel DuctsDucts DefectDefect SchemeScheme InterpretationInterpretation ofof IESIES DataData

• IES was performed every 6 inches vertically across the ducts • A direct echo from void has not been observed from the tests with a lower frequency • The only indication of void is a downshift in the dominant frequency resulting in an increase in thickness • Three dimensional surface plots are helpful with interpretation and visualization of defects InterpretationInterpretation ofof thethe IESIES DataData

F2 < F1 D2 > D1

F1 F2 InterpretationInterpretation ofof IESIES DataData

• Fully Grouted Duct – Frequency peak = 6,445 Hz – Apparent Thickness = 11.17 inches

• Empty Duct – Frequency peak = 5,274 Hz – Apparent Thickness = 13.65 inches Traditional Impact Echo Results Scanning across 4 Grouted Ducts

Time Domain IE Data

Spectrum 3D3D SurfaceSurface ThicknessThickness PlotPlot ResultsResults

Wall Height (ft) 0

0.8

1.6

2.4

3.2

4

4.8 06012018020 40 80 100 140 160 200 220 240 West End Length of Wall (inches) East End 3D3D SurfaceSurface ThicknessThickness PlotPlot ResultsResults ComparisonComparison ofof IESIES ResultsResults toto ActualActual DefectDefect DesignsDesigns –– TopTop DuctDuct

216” Wall Height (ft) 180” 144” 0 68%, 77% , 87% 72” 76% 84%, 94% %, 6%” 0.8 16

1.6

2.4

3.2

Defect can be identified clearly at length of 115 inches (from W. end) 4 Defect appears at length of 76 inches (from West end)

4.8 06012018020 40 80 100 140 160 200 220 240

West End Length of Wall (inches) East End ComparisonComparison ofof IESIES ResultsResults toto thethe ActualActual DefectDefect DesignsDesigns –– SecondSecond DuctDuct

Wall Height (ft) 240” 0 204” %, 6% Minor grout defect where 16 132” 76%, 87% there is no Styrofoam 0.8 16%, 6% 36”

1.6 24%, 13%

2.4

3.2 Worst defect area

Grout defect appear at 4 Grout defect appears at Lengths of 6 – 30” length of 135 inches

4.8 06012018020 40 80 100 140 160 200 220 240 West End Length of Wall (inches) East End ComparisonComparison ofof IESIES ResultsResults toto ActualActual DefectDefect DesignsDesigns –– ThirdThird DuctDuct

Wall Height (ft) 0

0.8 137” 101” 65” 2” 16%, 6% 1.6 ” 29 76%, 87% 16%, 6% 40%, 34% 32%, 23% 2.4

Grout defect where there 3.2 is no Styrofoam

Grout defect appears 4 from lengths of 84 - 126 inches

4.8 06012018020 40 80 100 140 160 200 220 240 West End East End Length of Wall (inches) ComparisonComparison ofof IESIES ResultsResults toto ActualActual DefectDefect DesignsDesigns –– BottomBottom DuctDuct

Wall Height (ft) 0

0.8

1.6

2.4

3.2

4

4.8 06012018020 40 80 100 140 160 200 220 240 West End Length of Wall (inches) East End MockupMockup SlabSlab atat BAMBAM FacilityFacility (Berlin(Berlin –– Germany)Germany)

• Size of slab – 10 x 4 meter • Typical slab thickness = 30 cm • One section contains tendons with voids • Another section provides varying thickness and voids IESIES TestTest onon thethe SlabSlab ThicknessThickness ResultsResults –– SimulatedSimulated StyrofoamStyrofoam VoidVoid Thickness (cm)

Thickness (cm) IESIES ResultsResults fromfrom aa DuctDuct

Completely Completely Completely Partially Filled Filled Empty Filled Empty Filled Empty

Interpretation of IES results from Duct C

Partially Filled Completely Filled EmptyCompletely Empty Completely Filled Filled

Actual Design Defect Locations in Duct C ImpactImpact EchoEcho ScanningScanning ofof GeorgeGeorge OrwellOrwell BridgeBridge overover thethe OrwellOrwell River,River, Ipswich,Ipswich, EnglandEngland

VerticalVertical ImpactImpact EchoEcho ScanScan withwith WellWell GroutedGrouted DuctsDucts inin 5252 cmcm thickthick wallwall sectionsection withwith 100100 mmmm ductsducts

O m at start of IE Grouted Ducts scan shown by Wall Echo of 52 cm thickness

2.0 m at end of IE scan VerticalVertical ImpactImpact EchoEcho ScanScan withwith 22 DuctDuct VoidsVoids ofof 3333 cmcm thickthick wallwall sectionsection withwith 100100 mmmm ductsducts

O m at start of IE Duct Voids shown scan by shift in thicknesses of 38 to 44 cm vs Wall Echo of 33 cm

1.8 m at end of IE scan 33--DD IEIE ScanScan DisplayDisplay showingshowing thickenedthickened endend andand possiblepossible thickerthicker vvoidedoided ductduct areasareas forfor 22 mm talltall wallwall overover 6262 mm lengthlength withwith verticverticalal tthicknesshickness scalescale ofof 100100 cmcm (1(1 m)m) NormalizedNormalized IEIE ThicknessThickness ofof DuctDuct GroutingGrouting ConditionsConditions

Discontinuity at 20 m. from the ref. Height (meter) (depth of 12 – 15 cm from the test surface) 0

0.4

0.8

1.2

1.6

2 21222 32 42 52 62 Distance (meter) Voids inside ducts Pier 2 Pier 3 NormalizedNormalized IEIE ThicknessThickness ofof DuctDuct GroutingGrouting ConditionsConditions

Void inside ducts Height (meter) 0

0.4

0.8

1.2

1.6

2 21222 32 42 52 62 Poor Data Quality Distance (meter) Pier 5 Pier 6 HighHigh EnergyEnergy XX--raysrays ofof SpecificSpecific DuctsDucts forfor CorrelationCorrelation withwith IEIE ScanningScanning SummarySummary

• The Impact Echo technique can be used to identify the internal grout conditions in PT Ducts • Impact Echo Scanner (IES) accelerates the IE test process • The use of IES makes it easier to generate the 3D surface plot • The 3D surface plot helps in interpretation and visualization of internal grout defects ImpactImpact EchoEcho ScanningScanning Training,Training, AdvantagesAdvantages andand DisadvantagesDisadvantages

• Near-continuous scanning with tests every inch at testing rates corresponding to slow walking speeds

• Identifies Thickness of Decks, Slabs and Pavements with good accuracy with 1-sided access

• 2-D and 3-D Imaging of internal flaws such as cracking, void, honeycomb and grouted vs. ungrouted post-tensioning ducts

• Requires specialized equipment, training and experience

• Will not penetrate open cracks and voids SpectralSpectral AnalysisAnalysis ofof SurfaceSurface WavesWaves (SASW)(SASW) MethodMethod

• Structural Concrete Curing, Freeze-Thaw, Crack Depth/Severity, etc.

• Pavement Systems Elastic Moduli and Thickness

• Seismic Velocity Subsurface Profiling for Seismic Design RayleighRayleigh WavesWaves

• Travel only on the free surface of a solid medium • Retrograde Elliptical Particle Motion only in the Vertical Plane • Dispersive – Velocity varies with Wavelength (λ) or Frequency (F) • Low frequency waves = High amplitude, Long Wavelengths, Deep Sampling

• VR  0.92 VS • Penetration Depth  0.4 λ FieldField SetupSetup CTGCTG --1SW1SW SurfaceSurface WaveWave VelocityVelocity TestTest onon GooseGoose CreekCreek BridgeBridge DeckDeck SASW velocity plot showing approximate thickness = 0.8 ft, surface wave velocity = 6,500 ft/s then IE velocity about 12,000 ft/s for normal quality deck concrete SpectralSpectral AnalysisAnalysis ofof SurfaceSurface WavesWaves Training,Training, AdvantagesAdvantages andand DisadvantagesDisadvantages

• CTG-1SW for Surface Wave Velocity (Vr) Measurement for Impact Echo Compressional Wave Velocity (Vp~Vr/0.56)

• Commercial Equipment available and Pushbutton to Windows Moderate Difficulty for use

• Identifies fire damage, frost damage, perpendicular cracks and concrete quality/strength with 1-sided access (ACI 228.2R-98) but requires background and training with experience

• Will not penetrate open cracks and voids Slab/StructuralSlab/Structural ImpulseImpulse ResponseResponse MethodMethod forfor StructuralStructural IntegrityIntegrity EvaluationEvaluation Slab Impulse Response on underside of pre-stressed box girder bridge showing 3 lb impulse hammer and geophone Example Slab Impulse Response record showing normal thickness (6.7 inches) concrete on a freight rail bridge

• Note the low mobility and flat slope indicative of the 6.7 inch thick slab of a box girder Example Slab Impulse Response record showing thin concrete (2.6 inches) on a light rail bridge

• Note irregular and higher mobility and steeper slope indicative of the much greater flexibility of the 2.6 inch thick (from IE tests) bottom slab of the box girder Slab/StructuralSlab/Structural ImpulseImpulse ResponseResponse Training,Training, AdvantagesAdvantages andand DisadvantagesDisadvantages

• Commercial Equipment available and Windows Easy to Moderate Difficulty for use

• Identifies Structural Soundness/Flaw conditions more globally

• Identifies near-surface Flaws such as Delamination, Void, Cracking, Honeycomb with Training and Experience

• Will not detect deeper flaws in thicker concrete as well NDENDE MethodsMethods forfor QAQA andand UnknownUnknown BridgeBridge SubstructureSubstructure andand FoundationFoundation ConditionsConditions

• Down-hole Methods • Surface Methods – Integrity Methods – Integrity and Length • Crosshole Sonic Logging (CSL) Method • Singlehole Sonic Logging (SSL) • Sonic Echo (SE) • Gamma-Gamma Density Method • Impulse Response (IR) • Crosshole Tomography (CT) • Ultraseismic – Length Methods • Impedance Image • Parallel Seismic (PS) • Induction Field • Borehole Radar NDE of Deep Foundations For QA of Concrete Placement with Crosshole Sonic Logging CSLCSL TestTest SetupSetup

• Equipment Required – 2 Hydrophones – 2 Cable Reels – Depth wheel – Data acquisition System CSLCSL TestTest SetupSetup

Freedom Data PC & CSL-2 System Hydrophones in the tubes Depth Wheel GeneralGeneral ApplicationsApplications andand AdvantagesAdvantages ofof CSLCSL TestingTesting forfor QAQA ofof DrilledDrilled ShaftsShafts

• Drilled Shaft Foundations and Diaphragm Walls • State Specifications • ASTM Standard D 6760-02 • Equipment commercially available • Technicians/Engineers readily trained • QA of Underwater, Risky Concrete Placement for Drilled Shaft Bridge Foundations ShaftShaft PreparationPreparation

• PVC or Steel (Best) Tubes Attached to Rebar Cage • Tubes Uniformly Distributed Around Perimeter • Tubes Capped at Bottom and Filled with Water • Typically 1 Tube per 1 ft of Diameter, Minimum of 2 Tubes

CSLCSL TestTest SetupSetup

Hydrophones in the tubes

Depth Wheel D HowHow doesdoes itit work?work? PVC or Steel Access Tubes Out of Cage Defect

T = 174 us

Severe Defect No Signal

T = 230 us

Small Defect

T = 174 us

Pulser Receiver CSLCSL DefectDefect GuidelinesGuidelines forfor ConcreteConcrete AcceptanceAcceptance andand StrengthStrength

Shaft Acceptance Criteria • Velocity <10% slower – Sound Concrete • 10% < Velocity - < 20 % slower - Questionable Concrete • < 20 % slower Velocity – Poor/Defect Concrete Concrete Strength Estimation (correlate to cores/cylinders) 4 • Faster Velocity = Stronger Concrete (V = f’c) • 10% slower velocity then 65% normal strength • 20% slower velocity then 42% normal strength MostMost CommonlyCommonly IdentifiedIdentified ConditionsConditions andand DefectsDefects inin CrossholeCrosshole SonicSonic LoggingLogging

• Sound Concrete • Soft Bottom Conditions • Soil Intrusions – loss of signal • Tremie Placement Problems – Concrete becomes – Water intrusions (velocity of water is 5,000 fps) – Soft layer in the shaft ExampleExample CSLCSL ResultResult -- SoundSound

Energy Arrival Time

Example Waveform

First Arrival Time = 200 us Energy is calculated from area under the envelope ExampleExample CSLCSL ResultResult -- AnomaliesAnomalies

Energy Arrival Time ExampleExample CSLCSL ResultResult -- AnomaliesAnomalies ExampleExample CSLCSL ResultResult -- TopographyTopography LimitationsLimitations ofof CSLCSL MethodsMethods

– Unable to detect defects outside the cage – Dependent on the bonding condition of the tubes and concrete and PVC tubes debond within 5-10 days, but steel tubes bond well sometimes up to 45+days – PVC tubes debond above water worst due to initial thermal curing and expansion and subsequent contraction as the concrete cools and then the tubes debond from the top down – Severity, size and shape of anomalies are average at best Crosshole Tomography (CT) Imaging Technology for Size, Shape and Extent of Defects in Drilled Shaft Foundations CrossholeCrosshole TomoGraphyTomoGraphy (CT)(CT)

• Use access tubes to test at many different angles above, below and through potential defect zones for tube pairs • Follow up CSL tests to image the size, shape and extent as well as severity of anomalies/defects found in CSL tests

CSL Crosshole Tomography CTCT InversionInversion ConceptConcept

• Straight-ray analysis • Curved Ray Velocity for initial tomograms tomograms for best images of flaws • Minimize errors with iterative analyses • Combine 2-D tomograms for 3-D images of flaws ExampleExample CSLCSL andand CTCT VelocityVelocity TomogramTomogram ResultsResults fromfrom DOTDOT BridgeBridge DrilledDrilled ShaftShaft FoundationFoundation Pier 2 Tubes 3 - 4

Soft Bottom Condition ExampleExample CSLCSL andand CTCT VelocityVelocity TomogramTomogram ResultsResults fromfrom DOTDOT BridgeBridge DrilledDrilled ShaftShaft FoundationFoundation Pier 2 Tubes 4 - 5

Soft Bottom Condition ExampleExample 2D2D CTCT ResultsResults fromfrom 66 PerimeterPerimeter TubeTube PairsPairs 1 2 3 4 56 1 ExampleExample CTCT ResultsResults fromfrom DiagonalDiagonal TubeTube PairsPairs

Tubes 1 - 4 Tubes 2 - 5 Tubes 3 - 6 ExampleExample 3D3D CTCT ResultsResults inin SoftSoft BottomBottom DefectDefect ZoneZone fromfrom aa HorizontalHorizontal VelocityVelocity TomogramTomogram SliceSlice 33--DD TomographicTomographic DisplaysDisplays ofof DefectsDefects

Rotate 3-D Horizontal Slice Y Slice Vertical Transparency for Defects Low Strain Integrity Testing of Deep Foundations – Sonic Echo/Impulse Response Methods FreedomFreedom DataData PCPC –– SonicSonic Echo/ImpulseEcho/Impulse ResponseResponse SystemsSystems

• Meets ASTM D5882 • Models available – SE – 1: for displaying echoes in time domain only. Includes accelerometer and dead blow hammer – SE/IR-1:combine the SE system with the IR system. Includes instrumented hammer, geophone and accelerometer SE/IR – 1 System

SE/IRSE/IR ResultsResults fromfrom FHWA/ADSCFHWA/ADSC DrilledDrilled ShaftShaft DefectDefect StudiesStudies

Acceleration vs. exponentially Amplified Velocity records in SE tests and SE/IR Results for Sound vs. 15% Area Defect

SonicSonic Echo/ImpulseEcho/Impulse ResponseResponse Training,Training, AdvantagesAdvantages andand DisadvantagesDisadvantages

• Commercial Equipment available and Pushbutton easty to Windows Easy to Moderate Difficulty for use • Identifies lengths and integrity of shafts and piles economically • Identifies defects about 25% of area and larger • Will not see below major defects • Limited to length to diameter ratios of 20:1 to 30:1 in stiffer • Complicated data interpretation for existing shafts and piles with attached superstructure NCHRP 21-5 Research Results for Unknown Subsurface Bridge Foundation Testing for Depth Determination Unknown USA Bridge Foundations •88,826 Bridges with unknown foundations - 2002 •26,000 identified as scour critical risk • Piles, Footings, Pilecaps of Concrete, Steel, Wood, Masonry • Questions - depth, foundation type, geometry & integrity UnknownUnknown FoundationFoundation SurfaceSurface NDENDE MethodsMethods forfor DepthDepth DeterminationDetermination

PSonic Echo/Impulse Response PBending Wave PUltraseismic PSpectral Analysis of Surface Waves Ultraseismic Method – Vertical Profiling Tri-axial Accelerometer for Ultraseismic Tests Bridge No. 5188, Minnesota Highway 58 Zumbrota, Minnesota UltraseismicUltraseismic TestTest ReceiverReceiver andand ImpactImpact LocationsLocations onon PierPier 5' below top of pier

Vertical hit on pier top generating flexural waves traveling down and up pier in 15' radial accelerometers of Ultraseismic test

1st echo at 23' - material change? and 2nd at 30.5 ft - bottom UltraseismicUltraseismic Training,Training, AdvantagesAdvantages andand DisadvantagesDisadvantages

• Commercial Equipment available and Windows Moderate Difficulty for use in field, experience and background required for data analysis • Identifies Unknown Foundation Depths of Exposed Pier, Abutment, and Piles and tracks reflections from foundation element bottom vs. misleading reflections from attached superstructure more accurately than Sonic Echo/Impulse Response • Will not detect piles below pilecaps due to most energy reflecting from the geometry/stiffness change UnknownUnknown FoundationFoundation BoreholeBorehole NDENDE MethodsMethods

• Parallel Seismic

• Induction Field

• Borehole Radar Parallel Seismic Method for Unknown Bridge Foundation Depth Determination

$ Determination of Foundation Depths, Typically with Superstructure on Top of Foundation

$ Requires Drilling a Hole Next to the Foundation within 5 ft or less preferably

$ Hole Should be at Least 15 ft Deeper than Expected Foundation Bottom ParallelParallel SeismicSeismic (PS)(PS) MethodMethod • Determination of Foundation Depths, Typically with Superstructure on Top of Foundation • Requires Drilling a Hole Next to the Foundation • Hole Should be at Least 3 m and preferably 4.5 m (10 to 15 ft) deeper than Expected Foundation Bottom ParallelParallel SeismicSeismic conceptconcept isis WaveWave EnerEnergygy travelstravels downdown ththee foundationfoundation fasterfaster thanthan throuthrougghh soilssoils andand itsits depthdepth iiss indicatedindicated bbyy aa weakerweaker andand slowerslower sisiggnalnal belowbelow itsits bottobottomm PSPS HardwareHardware ComponentsComponents

FreedomFreedom DataData PC,PC, Accelerometer,Accelerometer, HydrophoneHydrophone && HammerHammer forfor ImpactingImpacting ParallelParallel SeismicSeismic (PS)(PS) EquipmentEquipment

• PC Based Signal Analyzer • Single Hydrophone or 8-Channel Hydrophone for Rapid Testing • Receiver Amplifier and Filter • Impact Source, Usually 3 to 12 lb Hammers • Hydrophone is Placed in Drilled Hole • Hammer Impact is on Superstructure or Exposed Portion of Foundation if available

Length Determination of Timber Piles with Parallel Seismic Method for dredging of channel by Railroad Bridge in Southern California

PS Results for Timber Pile at RR Bridge Showing Bottom at 42.3 ft PS Results for Timber Pile at RR Bridge Showing Bottom at least 50 ft deep – not found due to boring not deep enough, but foundation deeper than required PSPS FieldField TestTest SetupSetup –– ImpactImpact PilesPiles BestBest PSPS SetupSetup –– ImpactImpact WallWall overover PilePile ExampleExample ofof PSPS DataData AcquisitionAcquisition Hydrophone Receiver response in volts versus time over period of 40960 us

1.4 kg Impulse Hammer Response from impact HawaiiHawaii RenovationRenovation ProjectProject atat PearlPearl HarborHarbor TestingTesting PSPS ResultsResults forfor ConcreteConcrete PilesPiles MoreMore PSPS ResultsResults ParallelParallel SeismicSeismic Training,Training, AdvantagesAdvantages andand DisadvantagesDisadvantages

• Commercial Equipment available and Windows Moderate Difficulty for use in field - experience and background required for data analysis

• Identifies Unknown Foundation Depths of all types of foundations including the most difficult which are H-piles below buried pilecaps

• Not sensitive to integrity of piles CONECONE PENETRATIONPENETRATION TESTTEST METHODSMETHODS A Brief Overview

Scott Slaughter, P.E. Southern Earth Sciences, Inc. Baton Rouge, LA “CPT 101”

CONE PENETRATION TEST (CPT)

A subsurface test process where an instrumented cone is pushed into the ground at a constant rate to continuously measure soil characteristics. Seismic Piezocone Test

DATA ACQUISITION SYSTEM REACTION PLATFORM

Cone Tip Stress, qc (corrected) VVs Penetration Porewater Pressure, u

Sleeve , fs ffs Arrival Time of Downhole Shear Wave, ts

ADDITIONAL CHANNELS INCLINATION PS/CPT u2 RESISTIVITY o VISION CONE u1 60 FFD ETC. qqc Electronic Cone Components

Strain Gauge (Sleeve)

Strain Gauge (Tip) Geophone

Tip Solid State Circuit Friction Sleeve Watertight Connector

Pore Pressure Element () HOGENTOGLER / VERTEK CPT/PARALLEL SEISMIC METHODS FOR UNKNOWN FOUNDATION DETERMINATION

Freedom Data PC

Hammer 10 ft. max Source 0 Arrival time (ms) 0

Compressional, Shear or Flesural Waves

Emission from Depth foundation (ft)

Depth of Foundation

Transmission from foundation Seismic Piezocone tip 4.5-tons weight 20-tons pushing capacity Lenoir County, North Carolina Bridge 5: HOG CPT 5

15 ) t f ( 11091. h t ep D

25

35 31.5

0 5 10 15 20 Travel Time (ms) Olson Engineering Island Station Development St. Paul, MN

Island Station Development St. Paul, MN

pstest4 10

30

1392.

50

65.3 ft

70 1446.

90

0 10 20 30 40 65.3 ft - ground surface to pile tip (20 ft) – ground surface to top of basement slab (4 ft) – 5 ft thick slab, 1 ft pile embedment in slab 41.3 ft Overall Embedded Pile Length Island Station Development St. Paul, MN

40 ft +/- CPT/ParallelCPT/Parallel SeismicSeismic atat OrangeOrange Beach,Beach, AlabamaAlabama Parallel Seismic - PSPC Concrete Driven Piling 5 PSSCPTPSSCPT TestingTesting ofof NewNew HydrophoneHydrophone ++ TriaxialTriaxial GeophoneGeophone ProbeProbe atat LALA 415415 inin BatonBaton Rouge,Rouge, LALA onon 2/12/072/12/07

PS/CPTPS/CPT ConclusionsConclusions

• PS/CPT Tests Gave Pile Tip Depths • Faster, more economical testing than with borings for PS test • Applicable to soft to stiff soils – not rock • PS/CPT with dummy tip and plastic casing • Added benefit of soil bearing/skin friction profile for scour susceptibility studies • US Patent approved ViewView fromfrom LeftLeft AbutmentAbutment RemotelyRemotely ActuatedActuated SonicSonic SourceSource TypicalTypical RaypathRaypath DistributionDistribution

• Average 17 source locations • 13 receiver locations • About 220 raypaths per station • Compressional and shear arrivals ExampleExample TomogramTomogram withwith AnomalousAnomalous AreasAreas

Debonded Joint inside the dam concrete Ground Penetrating Radar

2-D and 3-D Methods Ground Penetrating Radar (GPR)

• Electro-magnetic Wave Propagation • Usually Used in Reflection Surveys • Scanning is Supported • Several Antennae are Available: Range in Depth from 1.5 to 100 ft = Range in Antenna from 1500 to 25 MHz • Borehole Based Tomographic Imaging for Special Needs GPR Applications to Many Materials •Concrete • Masonry Walls •Asphalt Pavements •Soil GPR Structure, Infrastructure and Subsurface Applications • Structures - Locating Metal Objects in Concrete and Masonry, Particularly Steel Reinforcement and Post- Tensioned Ducts • Pavements - Determining Thickness of Asphalt and Concrete Pavement Surface Layers • , Slabs, Spillways, Pipes – Thickness and Condition of Concrete and Masonry elements • Subsurface - Location of Utilities and other Buried Objects in the Ground, Such as Pipes and Tanks GPR Scanning done along and across VA Bridge Deck with 1.5 GigaHertz Antennna Electromagnetic Wave Reflection Electromagnetic Wave Reflection Types in GPR Considerations for GPR Equipment Selection

• Depth of Penetration • Material Types • Existing Field Conditions • Density of Steel Reinforcement Scan patterns for clearing a proposed corehole in a slab with GPR – Crossing 2D Scans vs. 2D Grid Scans Data Acquisition

• Requires a clear area free of obstacles • Antenna is moved continuously over the surface • Data may be viewed immediately on the display screen GPR Data Analysis

• Affected by Dielectric Constant • Identify Two-Way Travel Time to Reflector Depths • Determine Depth of Reflector Based on a Known Velocity GPR Reflection Time to Depth Conversion

• Unit measures travel time of the wave • Reflector Time (T) converted to reflector depth (D) from Velocity of GPR electromagnetic wave

(VEM) calculated from speed of light (c) and material dielectric constant relative to air (Εr) 0.5 –VEM = c / Εr

–D = (VEM * T) / 2

• Velocity dependent on the materials dielectric constant Approximate Two-Way Travel Time for Common Materials

• Air , T = 2 ns/ft (2 nanoseconds/ft) • Water, T = 18 ns/ft • Dry Concrete, T = 4.5 ns/ft • Asphalt, T = 4.5 ns/ft • Dry , T = 4 ns/ft • Dry , T = 4 ns/ft • Wet sand, T = 7.5 ns/ft • Wet Clay, T = 10.5 ns/ft GPR Survey Setup for Structural Coring of Post- Tensioned and other Slabs

• Define scan pattern • Define grid spacing • Define a datum, relative to the surrounding area, to secure scan geometry • Place a scale along side your scan path and mark your start point (center of antenna) GPR Data Collection

• The antenna is pulled/pushed continuously across the test surface and the control unit collects data at the number of scans per unit distance. The data collection rate is independent of the pulling rate. GPR Field Data Review for Embedded Features Location

• Data is reviewed on the screen of the control unit to identify reflection from objects and to modify the survey lines accordingly. Locations are then recorded as they are read from the control unit. GPR Reflector Identification

ƒ All identified reflectors are marked out along each 2-D GPR Scan Line 3D GPR Embedded Features Model Generation

• Optional 3D Analysis and 3D Model Generation are performed using the REFLEX or RADAN software packages. Presented are two – 2D scan results for input as a 3D model generated from perpendicular scan lines over a concrete slab containing wire mesh. 2D GPR data showing a layer of rebar at 1.5 inches in depth and a second mat at 4 inches

Distance (in) Depth (in) Time (us) A 3D GPR Depth slice of a wall showing rebar mat and possible conduit (from 2 perpendicular 2D multiple scan datasets) 2-D GPR Waterfall Plot (Y = 28.0) for Slab PT Tendons & Dowels 2-D GPR Waterfall Plot Migrated (Y = 28.0) Tendons & Dowels 2-D GPR Waterfall Plot (X = 23.0) for main PT Tendons + Tendon Drape 2-D GPR Waterfall Plot (X = 23.0) w/ migrated PT Tendons + Tendon Drape 3-D GPR Plan View Time Slice Compilation (6 ns) for top down depth view of conduits and tendons (increasing time to right corresponds to increasing depth in to the slab) View of Post-Tensioning Strand Strongest GPR Reflectors GPR Tests Using a 1500 MHz Antenna on a Parking Lot GPR Scanning Tests on Asphalt Pavement of El Paso, Texas Airport Runway with 1 GHz Antenna and Distance Wheel GPR Test Results, Scanning and Using a 1200 MHz Antenna GPR Tests Using a 400 MHz Antenna to locate an Old Buried Wall Behind Expressway to ~ 10 ft ReinforcedReinforced ConcreteConcrete CorrosionCorrosion Activity,Activity, RateRate && ResistanceResistance TestsTests withwith GalvapulseGalvapulse InstrumentInstrument PotentialPotential ResponseResponse forfor CorrodingCorroding RebarRebar –– CorrosionCorrosion RateRate == 11.611.6 IIcorr/A/A LabLab ComparisonComparison byby BaesslerBaessler andand Burkert,Burkert, BAM,BAM, Berlin,Berlin, GermanyGermany showsshows GoodGood combinedcombined corrosioncorrosion comparisoncomparison GalvapulseGalvapulse ResultsResults fromfrom 3030 yryr oldold BridgeBridge ColumnColumn withwith highhigh chlorideschlorides duedue toto deicingdeicing saltssalts –– 4.44.4 mmmm lossloss perper yryr predictedpredicted andand destructivelydestructively confirmedconfirmed CorrosionCorrosion RateRate MeasurementsMeasurements atat aa LeakingLeaking JointJoint HighwayHighway bridgebridge columncolumn testtest –– steelsteel mustmust bebe electricallyelectrically contactedcontacted BridgeBridge WallWall TestTest GalvapulseGalvapulse onon heavilyheavily corrodedcorroded columncolumn –– higherhigher appliedapplied currentcurrent CorrosionCorrosion RateRate PlotPlot onon XX--YY GridGrid HalfHalf--CellCell PotentialPotential onon XX--YY GridGrid ElectricalElectrical ResistanceResistance onon XX--YY GridGrid Olson Instruments, Inc. Headquarters - Wheat Ridge, Colorado Olson Engineering, Inc. New York City, New York and San Francisco, California Olson Engineering has conducted Impact Echo, Ultrasonic Pulse Velocity and Spectral Analysis of Surface Waves tests of the concrete substructure and marble of the Lincoln Memorial in Washington, D.C. Olson Instruments, Inc. Headquarters - Wheat Ridge, Colorado Olson Engineering, Inc. New York City, New York and San Francisco, California Olson Engineering has conducted Ground Penetrating Radar, Vibration Monitoring, Impact Echo, Ultrasonic Pulse Velocity and Spectral Analysis of Surface Waves tests of the concrete substructure and marble of the Jefferson Memorial in Washington, D.C. Olson Instruments, Inc. Headquarters - Wheat Ridge, Colorado Olson Engineering, Inc. New York City, New York and San Francisco, California Olson Instruments Concrete Thickness Gauge used on Robot in the Cheops Pyramid by iRobot for a National Geographic TV Special “ Behind the Closed Door” in September, 2002

Giza Pyramid and Sphinx Olson Instruments, Inc. Headquarters - Wheat Ridge, Colorado Olson Engineering, Inc. New York City, New York and San Francisco, California Cheop’s (Khufu’s) Pyramid where CTG was used Olson Instruments, Inc. Headquarters - Wheat Ridge, Colorado Olson Engineering, Inc. New York City, New York and San Francisco, California

Stairs ascending from the King’s tomb in the Cheops Pyramid Olson Instruments, Inc. Headquarters - Wheat Ridge, Colorado Olson Engineering, Inc. New York City, New York and San Francisco, California

Vault going up into the internal chambers of the Cheops Pyramid Olson Instruments, Inc. Headquarters - Wheat Ridge, Colorado Olson Engineering, Inc. New York City, New York and San Francisco, California

Sarcophagus in the King’s tomb of the Cheops Pyramid Olson Instruments, Inc. Headquarters - Wheat Ridge, Colorado Olson Engineering, Inc. New York City, New York and San Francisco, California

Vault going into the Queen’s Chamber in the Cheop’s pyramid – Fox Television and National Geographic Investigation of what was behind a small Stone door at the end of a 250 foot long, 40 degree angled air shaft with a cross-secton of 8 x 8 inches Olson Instruments, Inc. Headquarters - Wheat Ridge, Colorado Olson Engineering, Inc. New York City, New York and San Francisco, California CTG Test Head Mounted to Pyramid Rover Robot of iRobot Link to National Geographic Special at www.olsoninstruments.com The robot crawled up to the stone door for 75 m at a 40 degree angle Olson Instruments, Inc. Headquarters - Wheat Ridge, Colorado Olson Engineering, Inc. New York City, New York and San Francisco, California CTG Test Head on Gaterbrinck’s Door – Impact Echo predicted 2-2.5 inches thick and drilling found door was 2 inches thick – Note 2 copper pins at top of 8 x 8 inch stone door Olson Instruments, Inc. Headquarters - Wheat Ridge, Colorado Olson Engineering, Inc. New York City, New York and San Francisco, California

Thanks! and Questions?