Designing and Detailing Post Tensioned Bridges to Accommodate Non-Destructive Evaluation

146 Pages·2015·3.67 MB·English

by  Christina P Cercone

Federal Highway Administration Project
DTFH61-11-H-0027
Advancing Steel and Concrete Bridge Technology to Improve
Infrastructure Performance
Task No. 11
Designing and Detailing Post Tensioned Bridges to Accommodate Non-
Destructive Evaluation
Subtask 11.1
Literature Review
January 2015
By
Christina Cercone
Clay Naito
John Corven
Stephen Pessiki
Wesley Keller
Shamim Pakzad
ATLSS REPORT NO. 14-01
ATLSS is a National Center for Engineering Research
on Advanced Technology for Large Structural Systems
117 ATLSS Drive
Bethlehem, PA 18015-4729
Phone: [phone] www.atlss.lehigh.edu
Fax: [phone] Email: [email protected]
Abstract
Post-tensioned concrete bridges represent a major component of the American bridge inventory. Many
new post-tensioned concrete bridges will be constructed to meet our infrastructure needs. Post-tensioning
(PT) tendons are comprised of prestressing strand, ducts, anchorages, grout, and corrosion protection
equipment. Current details for the construction of post-tensioning tendons do not facilitate the inspection
of the various tendon components. Recent cases of unexpected corrosion of post-tensioning tendons have
illustrated the importance of developing detailing changes that would allow improved inspection and
integration of nondestructive evaluation (NDE) methods.
The overall research program aims to develop guidance for the design and detailing of post-tensioned
bridges and tendon components to facilitate integration of NDE methods. The effort is focused on
evaluation of grouted internal and external post tensioning systems in precast I-girder, precast U-girder,
precast segmental box girder, and cast in-place box girder superstructures. Substructure elements are
outside the scope of this effort.
This report represents a brief overview of post-tensioned bridge construction and issues associated with
them. The current methods available for inspection are summarized and their benefits and limitations are
discussed. A comprehensive literature review on currently available NDE methods for post-tensioned
bridge systems is provided. The literature review focuses on NDE techniques that can be used to detect
the following issues in post–tensioned bridge girder systems: (1) Grout Voids/Condition, (2)
Strand/Anchorage Corrosion, and (3) Remaining Prestress Force. Within each of these categorizes NDE
techniques that can be used to identify issues with existing post-tensioned systems and NDE techniques
that can be integrated into new construction are presented. The literature review indicates that Electrically
Isolated Tendons, Embedded Half-Cell Methods, Time Domain Reflectometry and Ultrasonic Testing
Methods are promising detection tools that can be integrated into new construction. For existing
construction, other NDE methods may be useful. This includes: Impact Echo for grout void detection,
Magnetic Flux Leakage for corrosion, Radiography for corrosion and grout voids, Ground Penetrating
Radar for location of tendons, and Acoustic Emission for strand breakage. In all cases, visual techniques
should not be overlooked as they provide an effective tool for confirmation of in-situ damage during field
inspection.
ATLSS Report 14-01 FHWA Subtask 11.1 Page i
Table of Contents
1 Introduction ........................................................................................................................................... 1
2 Brief Overview on Post-tensioned Bridge Construction and Issues ..................................................... 2
2.1 Post-Tensioned Bridge Construction ............................................................................................ 2
2.1.1 Cast-in-Place Bridges on Falsework ..................................................................................... 2
2.1.2 Post-Tensioned AASHTO, Bulb-T, and Spliced Girders ..................................................... 3
2.1.3 Segmental Box Girder Bridges ............................................................................................. 3
2.1.4 Transverse Top Slab Post-Tensioning .................................................................................. 5
2.1.5 Post-Tensioning of Substructures ......................................................................................... 6
2.2 Post-Tensioned Components......................................................................................................... 7
2.2.1 Anchorages ........................................................................................................................... 7
2.2.2 Ducts ..................................................................................................................................... 9
2.2.3 Permanent Grout Caps ........................................................................................................ 10
2.2.4 Prestressing Strand .............................................................................................................. 11
2.2.5 Post-Tensioning Bars .......................................................................................................... 11
2.3 Damage Conditions Observed in PT Tendons ............................................................................ 12
2.3.1 Corrosion Along the Length of Internal Tendons ............................................................... 12
2.3.2 Cantilever Tendon Corrosion through Segment Joints ....................................................... 13
3.3.3 External Tendon Failure by Corrosion at the Anchorages .................................................. 13
2.3.3 Cases of Post-Tensioned Tendon Corrosion ....................................................................... 14
3 Overview of Applicable Inspection Methods ..................................................................................... 16
3.1 Acoustic Emission ...................................................................................................................... 16
3.1.1 Applications ........................................................................................................................ 16
3.1.2 Methodology ....................................................................................................................... 16
3.1.3 Limitations .......................................................................................................................... 18
3.1.4 Viability in Post-Tensioned Applications ........................................................................... 18
3.1.5 References ........................................................................................................................... 19
3.2 Electrically Isolated Tendons ...................................................................................................... 19
3.2.1 Applications ........................................................................................................................ 19
3.2.2 Methodology ....................................................................................................................... 20
3.2.3 Limitations .......................................................................................................................... 23
3.2.4 Viability in Post-Tensioned Applications ........................................................................... 24
3.2.5 References ........................................................................................................................... 24
3.3 Ground Penetrating Radar ........................................................................................................... 25
3.3.1 Applications ........................................................................................................................ 25
3.3.2 Methodology ....................................................................................................................... 25
ATLSS Report 14-01 FHWA Subtask 11.1 Page ii
3.3.3 Limitations .......................................................................................................................... 28
3.3.4 Viability in Post-Tensioned Applications ........................................................................... 29
3.3.5 References ........................................................................................................................... 30
3.4 Half-Cell Potential ...................................................................................................................... 31
3.4.1 Applications ........................................................................................................................ 31
3.4.2 Methodology ....................................................................................................................... 31
3.4.3 Limitations .......................................................................................................................... 34
3.4.4 Viability in Post-Tensioned Applications ........................................................................... 34
3.4.5 References ........................................................................................................................... 35
3.5 Impact Echo ................................................................................................................................ 35
3.5.1 Applications ........................................................................................................................ 35
3.5.2 Methodology ....................................................................................................................... 36
3.5.3 Limitations .......................................................................................................................... 37
3.5.4 Viability in Post-Tensioned Applications ........................................................................... 37
3.5.5 References ........................................................................................................................... 37
3.6 Infrared Thermography ............................................................................................................... 39
3.6.1 Applications ........................................................................................................................ 39
3.6.2 Methodology ....................................................................................................................... 39
3.6.3 Limitations .......................................................................................................................... 40
3.6.4 Viability in Post-Tensioned Applications ........................................................................... 40
3.6.5 References ........................................................................................................................... 40
3.7 Magnetic Flux Leakage ............................................................................................................... 41
3.7.1 Applications ........................................................................................................................ 41
3.7.2 Methodology ....................................................................................................................... 41
3.7.3 Limitations .......................................................................................................................... 44
3.7.4 Viability in Post-Tensioned Applications ........................................................................... 44
3.7.5 References ........................................................................................................................... 44
3.8 Radiography ................................................................................................................................ 45
3.8.1 Applications ........................................................................................................................ 45
3.8.2 Methodology ....................................................................................................................... 45
3.8.3 Limitations .......................................................................................................................... 47
3.8.4 Viability in Post-Tensioned Applications ........................................................................... 47
3.8.5 References ........................................................................................................................... 48
3.9 Signal Processing for Defect Detection ...................................................................................... 48
3.9.1 Applications ........................................................................................................................ 48
3.9.2 Methodology and Applications ........................................................................................... 49
ATLSS Report 14-01 FHWA Subtask 11.1 Page iii
3.9.3 References ........................................................................................................................... 51
3.10 Time Domain Reflectometry ...................................................................................................... 52
3.10.1 Applications ........................................................................................................................ 52
3.10.2 Methodology ....................................................................................................................... 52
3.10.3 Limitations .......................................................................................................................... 55
3.10.4 Viability in Post-Tensioned Applications ........................................................................... 56
3.10.5 References ........................................................................................................................... 56
3.11 Ultrasonic Testing ....................................................................................................................... 56
3.11.1 Applications ........................................................................................................................ 56
3.11.2 Methodology ....................................................................................................................... 57
3.11.3 Limitations .......................................................................................................................... 58
3.11.4 Viability in Post-Tensioned Applications ........................................................................... 59
3.11.5 References ........................................................................................................................... 59
3.12 Visual Inspection ........................................................................................................................ 60
3.12.1 Applications ........................................................................................................................ 60
3.12.2 Methodology ....................................................................................................................... 60
3.12.3 Limitations .......................................................................................................................... 61
3.12.4 Viability in Post-Tensioned Applications ........................................................................... 61
3.12.5 References ........................................................................................................................... 61
4 Summary of NDE methods and tools ................................................................................................. 63
4.1 Future Work ................................................................................................................................ 65
5 Agency Sponsored Studies.................................................................................................................. 67
5.1 Department of Transportation Reports ....................................................................................... 67
5.1.1 Improved Inspection Techniques for Steel Prestressing/Post-tensioning Strand – Final
Report –Volume 1 ............................................................................................................................... 67
5.1.2 FDOT Protocol for Condition Assessment of Steel Strands in Post-tensioned Segmental
Concrete Bridges- Final Report – Volume II ...................................................................................... 67
5.1.3 Inspection Methods and Techniques to Determine Non Visible Corrosion of Prestressing
Strands in Concrete Bridge Components Task 2 – Assessment of Candidate NDT Methods ............ 68
5.1.4 Inspection Methods and Techniques to Determine Non Visible Corrosion of Prestressing
Strands in Concrete Bridge Components Task 3 - Forensic Evaluation and Rating Methodology .... 69
5.1.5 Nondestructive Method to Detect Corrosion of Steel Elements in Concrete ...................... 69
5.1.6 Effect of Voids in Grouted, Post-Tensioned Concrete Bridge Construction: Volume 1 –
Electrochemical Testing and Reliability Assessment ......................................................................... 70
5.1.7 Detection of Voids in Prestressed Concrete Bridges using Thermal Imaging and Ground-
Penetrating Radar ................................................................................................................................ 71
5.1.8 New Directions for Florida Post-Tensioned Bridges – Load Rating Post-Tensioned
Concrete Segmental Bridges (Volume 10A)....................................................................................... 71
ATLSS Report 14-01 FHWA Subtask 11.1 Page iv
5.1.9 New Directions for Florida Post-Tensioned Bridges – Load Rating Post-Tensioned
Concrete Beam Bridges (Volume 10B) .............................................................................................. 72
5.1.10 Evaluating Nondestructive Testing Techniques to Detect Voids in Bonded Post-Tensioned
Ducts – Final Report ........................................................................................................................... 72
5.1.11 Test and Assessment of NDT Methods for Post-Tensioning Systems in Segmental
Balanced Cantilever Concrete Bridges ............................................................................................... 72
5.1.12 New Directions for Florida Post-Tensioned Bridges – Post-Tensioning in Florida Bridges
(Volume 1) .......................................................................................................................................... 75
5.1.13 New Directions for Florida Post-Tensioned Bridges – Design and Construction Inspection
of Precast Segmental Balanced Cantilever Bridges (Volume 2) ........................................................ 75
5.1.14 New Directions for Florida Post-Tensioned Bridges –Design and Construction Inspection
of Precast Segmental Span-By-Span Bridges (Volume 3) .................................................................. 75
5.1.15 New Directions for Florida Post-Tensioned Bridges- Design and Construction Inspection
of Precast Concrete Spliced I-Grider Bridges (Volume 4) ................................................................. 76
5.1.16 New Directions for Florida Post-Tensioned Bridges - Design and Construction Inspection
of Cast-In-Place Segmental Balanced Cantilever Bridges (Volume 5) .............................................. 76
5.1.17 New Directions for Florida Post-Tensioned Bridges - Design and Construction Inspection
of Bridges Cast-In-Place on Falsework (Volume 6) ........................................................................... 76
5.1.18 New Directions for Florida Post-Tensioned Bridges – Design and Construction of Post-
Tensioned Substructures ..................................................................................................................... 76
5.1.19 New Directions for Florida Post-Tensioned Bridges – Design and Construction of
Transverse Post-Tensioning of Superstructures (Volume 8) .............................................................. 77
5.1.20 New Directions for Florida Post-Tensioned Bridges – Condition Inspection and
Maintenance of Florida Post-Tensioned Bridges (Volume 9) ............................................................ 77
5.1.21 Mid-Bay Bridge Post-Tensioning Evaluation ..................................................................... 77
5.1.22 Initial Development of Methods for Assessing Condition of Post-Tensioned Tendons of
Segmental Bridges .............................................................................................................................. 78
5.1.23 Tensile Test Results of Post Tensioning Cables from the Midbay Bridge ......................... 79
5.1.24 Corrosion Evaluation of Post-Tensioned Tendons in Florida Bridges ............................... 79
5.2 ACI Reports ................................................................................................................................ 80
5.2.1 Corrosion of Prestressing Steels (ACI 222.2R-01) ............................................................. 80
5.3 NCHRP Reports .......................................................................................................................... 80
5.3.1 Non-Destructive Evaluation Method for Determination of Internal Grout Conditions inside
Bridge Post-Tensioning Ducts using Rolling Stress Waves for Continuous Scanning ...................... 80
5.3.2 Nondestructive Methods for Condition Evaluation of Prestressing Steel Strands in
Concrete Bridges, Final Report Phase I: Technology Review ............................................................ 81
5.4 Federal Highway Administration (FHWA) ................................................................................ 82
5.4.1 Conclusions, Recommendations and Design Guidelines for Corrosion Protection of Post-
Tensioned Bridges .............................................................................................................................. 82
5.4.2 Improving Bridge Inspections ............................................................................................. 82
ATLSS Report 14-01 FHWA Subtask 11.1 Page v
5.4.3 Magnetic-Based NDE of Prestressed and Post-Tensioned Concrete Members – The MFL
System 82
5.4.4 Demonstration of Dual-Band Infrared Thermal Imaging for Bridge Inspection ................ 83
5.5 ASTM Standards ......................................................................................................................... 84
5.5.1 ASTM A 36 -12: Standard Specification for Carbon Structural Steel ................................ 84
5.5.2 ASTM A 53 -12: Standard Specification for Pipe, Steel, Black and Hot-Dipped, Zinc-
Coated, Welded and Seamless ............................................................................................................ 84
5.5.3 ASTM A 240 -13: Standard Specification for Chromium and Chromium-Nickel Stainless
Steel Plate, Sheet, and Strip for Pressure Vessels and for General Applications................................ 84
5.5.4 ASTM A 416 -12: Standard Specification for Steel Strand, Uncoated Seven-Wire for
Prestressed Concrete ........................................................................................................................... 85
5.5.5 ASTM A 653 -13: Standard Specification for Steel Sheet, Zinc-Coated (Galvanized) or
Zinc-Iron Alloy-Coated (Galvannealed) by the Hot-Dip Process ....................................................... 85
5.5.6 ASTM A 722 -12: Standard Specification for Uncoated High-Strength Steel Bars for
Prestressing Concrete .......................................................................................................................... 85
5.5.7 ASTM C876 – 09: Standard Test Method for Corrosion Potentials of Uncoated
Reinforcing Steel in Concrete ............................................................................................................. 85
5.5.8 ASTM D 1693 -13: Standard Test Method for Environmental Stress-Cracking of Ethylene
Plastics 85
5.5.9 ASTM D4101-14: Standard Specification for Polypropylene Injection and Extrusion
Materials 85
5.5.10 ASTM F 405 – 13: Standard Specification for Corrugated Polyethylene (PE) Pipe and
Fittings 85
5.6 Other ........................................................................................................................................... 86
5.6.1 Post-tensioned Multistrand Anchorage Capacity Deterioration Due to Corrosion: John Day
Lock Project ........................................................................................................................................ 86
5.6.2 Guide Specification for Grouted Post-Tensioning .............................................................. 86
5.6.3 Quality Control and Monitoring of Electrically Isolated Post-Tensioning Tendons in
Bridges 86
5.6.4 Swiss Guideline Measures to Ensure Durability of Post-Tensioning Tendons in Structures
87
6 Grout Condition .................................................................................................................................. 89
6.1 Application of Gamma Ray Scattering Technique for Non-Destructive Evaluation of Voids in
Concrete .................................................................................................................................................. 89
6.2 Quantitative Evaluation of Contactless Impact Echo for Non-Destructive Assessment of Void
Detection within Tendon Ducts .............................................................................................................. 89
6.3 Non-Destructive Testing Methods to Identify Voids in External Post-Tensioned Tendons ....... 89
6.4 Detecting Voids in Grouted Tendon Ducts of Post-Tensioned Concrete Structures Using Three
Different Methods ................................................................................................................................... 90
6.5 Concrete Bridge Condition Assessment with Impact Echo Scanning ........................................ 90
6.6 Inspection of Voids in External Tendons of Posttensioned Bridges ........................................... 90
ATLSS Report 14-01 FHWA Subtask 11.1 Page vi
6.7 Modified SIBIE Procedure for Ungrouted Tendon Ducts Applied to Scanning Impact-Echo ... 91
6.8 On-Site Measurement of Delamination and Surface Crack in Concrete Structure by Visualized
NDT 91
6.9 Identification of Ungrouted Tendon Duct in Prestressed Concrete by SIBIE ............................ 91
6.10 Estimation of Surface-Crack Depth in Concrete by Scanning SIBIE Procedure ........................ 92
6.11 Imaging of Internal Cracks in Concrete Structures Using the Surface Rendering Technique .... 92
6.12 Ultrasonic Imaging Methods for Investigation of Post-tensioned Concrete Structures: A Study
of Interfaces at Artificial Grouting and Its Verification .......................................................................... 93
6.13 Imaging Concrete Structures Using Air-Coupled Impact-Echo ................................................. 93
6.14 Impact-Echo Scanning Evaluation of Grout/Void Conditions Inside Bridge Post-Tensioning
Ducts for Tendon Corrosion Mitigation .................................................................................................. 93
6.15 Impact-Echo Scanning for Grout Void Detection in Post-tensioned Bridge Ducts - Findings
from a Research Project and a Case History ........................................................................................... 94
6.16 Sensitivity Studies of Grout Defects in Posttensioned Bridge Ducts Using Impact Echo
Scanning Method .................................................................................................................................... 94
6.17 Imaging of Ungrouted Tendon Ducts in Prestressed Concrete by Improved SIBIE................... 95
6.18 Automated NDE of Post-Tensioned Concrete Bridges Using Imaging Echo Methods .............. 95
6.19 Impact Echo Scanning for Discontinuity Detection and Imaging in Posttensioned Concrete
Bridges and Other Structures .................................................................................................................. 96
6.20 Complementary Application of Radar, Impact-Echo and Ultrasonics for Testing Concrete
Structures and Metallic Tendon Ducts .................................................................................................... 96
6.21 Contribution of Capacitance Probes for Nondestructive Inspection of External Post-Tensioned
Ducts 97
6.22 Ultrasonic Imaging of Concrete Elements Using Reconstruction by Synthetic Aperture
Focusing Technique ................................................................................................................................ 97
6.23 Ultrasonic Guided Waves for Inspection of Grouted Tendons and Bolts ................................... 97
6.24 Guidance on the use of NDE on Voided Post-Tensioned Concrete Bridge Beams using Impact
Echo 98
6.25 Use of the MegascanTM Imaging Process in Inspection Systems for Post-Tensioned Bridges and
Other Major Structures ........................................................................................................................... 98
6.26 Comparison of NDT Techniques on a Post-Tensioned Beam Before its Autopsy ..................... 98
6.27 Stack Imaging of Spectral Amplitudes Based on Impact-Echo for Flaw Detection ................... 99
6.28 Applications of Impact-Echo for Flaw Detection ....................................................................... 99
6.29 Ultrasonic Tomography of Grouted Duct Post-Tensioned Reinforced Concrete Bridge Beams 99
6.30 : Nondestructive Evaluation of Concrete and Masonry ............................................................ 100
6.31 Detecting Voids in Grouted Tendon Ducts of Post-Tensioned Concrete Structures using the
Impact Echo Method ............................................................................................................................. 100
7 Strand Corrosion ............................................................................................................................... 101
7.1 Acoustic Emission Monitoring of Reinforced Concrete under Accelerated Corrosion ............ 101
7.2 Corrosion Damage Quantification of Prestressing Strands using Acoustic Emission .............. 101
ATLSS Report 14-01 FHWA Subtask 11.1 Page vii
7.3 Detection of Corrosion of Post-Tensioned Strands in Grouted Assemblies ............................. 101
7.4 Monitoring of Electrically Isolated Post-Tensioning Tendons ................................................. 102
7.5 Evaluation of NDT Methods for Detection of Prestressing Steel Damage at Post-Tensioned
Concrete Structures ............................................................................................................................... 102
7.6 Enhanced Durability, Quality Control and Monitoring of Electrically Isolated Tendons ........ 103
7.7 Corrosion of the Strand-Anchorage System in Post-Tensioned Grouted Assemblies .............. 103
7.8 Long-Term Monitoring of Electrically Isolated Post-Tensioning Tendons .............................. 103
7.9 Electrical Isolation as Enhanced Protection for Posttensioning Tendons in Concrete Structures
(PL3) 104
7.10 Experience with Electrically Isolated Tendons in Switzerland ................................................. 104
7.11 Protection Against Corrosion and Monitoring of Posttensioning Tendons in Prestressed
Concrete Railway Bridges in Italy ........................................................................................................ 104
7.12 Corrosion Protection and Monitoring of Electrically Isolated Post-Tensioning Tendons ........ 105
7.13 Mechanism of Corrosion of Steel Strands in Post Tensioned Grouted Assemblies ................. 105
7.14 Location of Prestressing Steel Fractures in Concrete ............................................................... 105
7.15 Half-Cell Potential Measurements – Potential Mapping on Reinforced Concrete Structures .. 106
7.16 Ultrasonic Imaging – A Novel Way to Investigate Corrosion Status in Post-Tensioned Concrete
Members ............................................................................................................................................... 106
7.17 Comparison of NDT Techniques on a Post-Tensioned Beam Before its Autopsy ................... 106
7.18 Recent Developments in SQUID NDE ..................................................................................... 107
7.19 SQUID Array for Magnetic Inspection of Prestressed Concrete Bridges ................................. 107
7.20 Continuous Acoustic Monitoring of Grouted Post-Tensioned Concrete Bridges ..................... 107
8 Strand Location ................................................................................................................................. 109
8.1 Application of Ground Penetrating Radar (GPR) as a Diagnostic Technique in Concrete Bridge
109
8.2 Rebar Detection Using GPR: An Emerging Non Destructive QC Approach ........................... 109
8.3 Results of Reconstructed and Fused NDT Data Measured in the Laboratory and On-Site
Bridges .................................................................................................................................................. 110
8.4 Ground Penetrating Radar for Concrete Evaluation Studies ..................................................... 110
8.5 Complementary Application of Radar, Impact-Echo and Ultrasonics for Testing Concrete
Structures and Metallic Tendon Ducts .................................................................................................. 110
8.6 Nondestructive Evaluation of Concrete Infrastructure with Ground Penetrating Radar ........... 111
8.7 Comparison of NDT Techniques on a Post-Tensioned Beam Before its Autopsy ................... 111
8.8 Condition Assessment of Transportation Infrastructure Using Ground-Penetrating Radar ...... 111
8.9 Automated NDE of PT Concrete Structures ............................................................................. 112
9 Remaining Prestress .......................................................................................................................... 113
9.1 Detection of Initial Yield and Onset of Failure in Bonded Post-Tensioned Concrete Beams .. 113
9.2 Estimation of Existing Prestress Level on Bonded Strand Using Impact-Echo Test ................ 113
ATLSS Report 14-01 FHWA Subtask 11.1 Page viii
9.3 Determination of the Residual Prestress Force of In-Service Girders using Non-Destructive
Testing113
9.4 Non-Destructive Evaluation of the Stress Levels in Prestressed Steel Strands using
Acoustoelastic Effect ............................................................................................................................ 114
9.5 Health Monitoring to Detect Failure of Prestressing (PS) Cables in Segmental Box-Girder
Bridges .................................................................................................................................................. 114
9.6 A Smart Steel Strand for the Evaluation of Prestress Loss Distribution in Post-Tensioned
Concrete Structures ............................................................................................................................... 115
9.7 Comparison of Prestress Losses for a Prestress Concrete Bridge Made with High-Performance
Concrete ................................................................................................................................................ 115
9.8 Ultrasonic Wave Propagation in Progressively Loaded Multi-Wire Strands ........................... 115
9.9 Application of a New Nondestructive Evaluation Technique to a 25-Year-Old Prestressed
Concrete Girder ..................................................................................................................................... 116
10 NDE Methods with Multiple Applications ................................................................................... 117
10.1 Guidelines for the Thermographic Inspection of Concrete Bridge Components in Shaded
Conditions ............................................................................................................................................. 117
10.2 Comparison of NDT Methods for Assessment of a Concrete Bridge Deck ............................. 117
10.3 Use of Neutron Radiography and Tomography to Visualize the Autonomous Crack Sealing
Efficiency in Cementitious Materials ................................................................................................... 118
10.4 Commissioning of Portable 950 keV/3.95 MeV X-band Linac X-Ray Sources for On-Site
Transmission Testing ............................................................................................................................ 118
10.5 Non-Destructive Radiographic Evaluation and Repairs to Pre-Stressed Structure Following
Partial Collapse ..................................................................................................................................... 119
10.6 Application of Thermal IR Imagery for Concrete Bridge Inspection ....................................... 119
10.7 Gamma-Ray Inspection of Post Tensioning Cables in a Concrete Bridge ............................... 119
10.8 Environmental Effects on Subsurface Defect Detection in Concrete Structures Using Infrared
Thermography ....................................................................................................................................... 120
10.9 Gamma-Ray Imaging for Void and Corrosion Assessment in PT Girders ............................... 120
10.10 Evaluation of Radar and Complementary Echo Methods for NDT of Concrete Elements... 120
10.11 Thermographic Crack Detection by Eddy Current Excitation .............................................. 121
10.12 Results of Reconstructed and Fused NDT Data Measured in the Laboratory and On-Site
Bridges 121
10.13 Time-Domain Reflectometry to Detect Voids in Posttensioning Ducts ............................... 121
10.14 Ultrasonic C-Scan Imaging of Post-Tensioned Concrete Bridge Structures for Detection of
Corrosion and Voids ............................................................................................................................. 122
10.15 Progress in Ultrasonic Imaging of Concrete ......................................................................... 122
10.16 Recent Research in Nondestructive Evaluation of Civil Infrastructures ............................... 123
10.17 Detecting Corrosion in Existing Structures Using Time Domain Reflectometry ................. 123
10.18 Ultrasonic C-scan Imaging: Preliminary Evaluation for Corrosion and Void Detection in
Posttensioned Tendons .......................................................................................................................... 124
ATLSS Report 14-01 FHWA Subtask 11.1 Page ix