Guidelines for Embedment Length of Carbon Fiber Reinforced Polymer (CFRP) Strips in Near Surface Mount (NSM) Retrofitted Concrete Structures

The Near Surface Mount-Carbon Fiber Reinforced Polymer (NSM-CFRP) method for retrofitting is becoming an effective way of strengthening reinforced concrete structures compared to the conventional external bonded retrofitting (EBR) technique. This can be attributed to increased stiffness and strength resulting from the significantly more effective bonding in the NSM method. In this method grooves are cut on the concrete surface, epoxy is filled in and then CFRP reinforcement is inserted in the slits. The commonly used CFRP reinforcements for strengthening in the NSM method are round and square/rectangular bars. Recent studies have shown narrow rectangular CFRP strips to be highly effective and more economical than round or rectangular bars in resisting static, fatigue and impact loads. However, research highlights the need to provide larger development length for these strips than what is recommended by ACI 440.2R-08 [1] to avoid premature failure. There is also clear lack in the literature for the recommended embedment length of CFRP strips in concrete owing to limited experimental data. It is also noteworthy that the development length formula for rectangular reinforcements given in ACI 440.2R-08 is only applicable to normal strength concrete (i.e. up to 5000 psi) and it does not distinguish between flexural and compression strengthening. However, in-situ concrete strengths are often found to be well above this limit and CFRP strips are known to perform differently in tension and compression. As a result, the use of same formulation for both cases cannot be justified. Finally, although rectangular in nature, CFRP strips should be treated differently than conventional square/rectangular reinforcements due to higher stress concentrations at the edges. All these factors provide impetus for this research project.

Language

  • English

Project

  • Status: Active
  • Funding: $100000.00
  • Contract Numbers:

    DTRT12-G-UTC16

    CAIT-UTC-036

  • Sponsor Organizations:

    Center for Advanced Infrastructure and Transportation

    Rutgers University
    100 Brett Rd
    Piscataway, NJ  United States  08854-8058

    Delaware Department of Transportation

    800 S. Bay Road
    P.O. Box 778
    Dover, DE  United States  19903

    Research and Innovative Technology Administration

    University Transportation Centers Program
    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Project Managers:

    Szary, Pat

    Arndt, Jason

  • Performing Organizations:

    Center for Advanced Infrastructure and Transportation

    Rutgers University
    100 Brett Rd
    Piscataway, NJ  United States  08854-8058
  • Principal Investigators:

    Ramanna, Nakul

  • Start Date: 20140101
  • Expected Completion Date: 0
  • Actual Completion Date: 20150430
  • Source Data: RiP Project 35634

Subject/Index Terms

Filing Info

  • Accession Number: 01550054
  • Record Type: Research project
  • Source Agency: Center for Advanced Infrastructure and Transportation
  • Contract Numbers: DTRT12-G-UTC16, CAIT-UTC-036
  • Files: UTC, RiP
  • Created Date: Jan 16 2015 1:00AM