Methods for Detecting Defects in Composite Rehabilitated Concrete Structures

Fiber reinforced polymer (FRP) composites are increasingly being used to rehabilitate under-strength or deteriorating concrete structural elements and to prolong useful service-life of bridge structures. The rehabilitation is conducted through the external bonding of FRP strips onto the concrete substrate using either the wet layup process or the adhesive bonding of prefabricated strips. While the method has been shown to be extremely effective, there is a need for the development of expertise relating to identification of defects during inspection. This report addresses four specific aspects of defect identification: (1) identification of the types of defects in composite strengthened concrete structural elements; (2) determination of the potential effect of selected defects on the performance and integrity of the structural system; (3) identification of state-of-the-art quality assurance and non-destructive evaluation (NDE) technologies that can be used for detecting defects; and (4) preliminary investigation of selected technologies that have a high likelihood of being successfully used for purposes of quality assurance. Potential defects are identified, classified by type and stage at which they could occur, and their effects are listed. Criticality of selected defect types is assessed using an experimental fracture mechanics based approach. The range of NDE techniques identified is assessed based on pertinent characteristics required for inspection in the field, and the techniques are classified based on applicability. Two techniques – thermography (representative of a non-contact local technique) and vibration based modal analysis coupled with a damage detection approach (representative of a global technique) – are explained in more depth with examples of use.

• Corporate Authors:

  Oregon Department of Transportation

  Research Section, 200 Hawthorne Avenue, SE, Suite B-240
  Salem, OR  United States  97301-5192

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Karbhari, Vistasp M
  • Kaiser, Henning
  • Navada, Rajiv
  • Ghosh, Kumar
  • Lee, Luke
• Publication Date: 2005-4

Language

• English

Media Info

• Media Type: Print
• Edition: Final Report
• Features: Appendices; Figures; Photos; References; Tables;
• Pagination: 424p

Subject/Index Terms

• TRT Terms: Concrete structures; Deterioration; Fiber composites; Fiber reinforced polymers; Nondestructive tests; Quality assurance; Rehabilitation (Maintenance); Service life; State of the art; Structural deterioration and defects
• Uncontrolled Terms: Substrates
• Subject Areas: Bridges and other structures; Design; Highways; Maintenance and Preservation; I24: Design of Bridges and Retaining Walls; I60: Maintenance;

Filing Info

• Accession Number: 01076678
• Record Type: Publication
• Report/Paper Numbers: FHWA-OR-RD-05-09
• Contract Numbers: SPR 336
• Files: TRIS, USDOT, STATEDOT
• Created Date: Sep 5 2007 6:11PM