Long-Term Performance of Epoxy Adhesive Anchor Systems

Epoxy adhesive anchor systems have widespread use throughout the world. They are used to anchor both threaded rods and reinforcing bar into hardened concrete. Common transportation applications for epoxy adhesive anchor systems include bridge widening, structure-mounted signs and appurtenances, luminaires and light poles, concrete repair and rehabilitation, barrier retrofitting, utility installation on existing structures, and tunneling finishing. In July 2006, a section of a suspended concrete ceiling failed and collapsed in the D Street Portal of the Interstate 90 connecter tunnel (part of the "Big Dig") in Boston, Massachusetts. This was a rapid and catastrophic failure that resulted in the loss of life. In July 2007, the National Transportation Safety Board (NTSB) issued a report tracing the cause of this collapse to the failure of epoxy bonded anchors that held the suspended ceiling in place (SB-07-36). NTSB cited a poor creep resistance of the epoxy resin and a general lack of understanding and knowledge about creep in adhesive anchoring systems. </font><font size="3">Epoxy bonding systems have widespread use throughout the world. These systems are used to anchor both threaded rods and reinforcing bar into hardened concrete. Common transportation applications for epoxy bonded anchors include bridge widening, concrete repair and rehabilitation, barrier retrofitting, utility installation on existing structures, and tunneling. Despite widespread use, the suppliers of these systems provide little guidance on how the adhesives perform under sustained, long-term loading. The long-term behavior needs further investigation to prevent failures like the one in Boston. </font><font size="3">Finally, the AASHTO LRFD Bridge Design Specification doesn't adequately address the use of epoxy adhesive anchors. The results of this research will be crucial in the development of appropriate guidelines for AASHTO. </font><font size="3">The objectives of this project are the following: (1) through testing and numerical modeling, if needed, document the long-term characteristics of epoxy adhesives currently in use, with emphasis on identifying what levels of sustained loading pose a risk to anchor performance; (2) develop standards and protocols for the testing and use of adhesive anchors in sustained loading applications; (3) provide guidance for future use of adhesive anchors, including (a) identifying the creep performance requirements that are necessary for acceptance of an adhesive anchor system, and (b) developing acceptance criteria that are a function of application, with epoxy anchors not subjected to sustained loading having different acceptance criteria than anchors that will have sustained loading; (4) provide recommendations for agencies for the use of adhesive anchors in sustained loading applications, including (a) how to identify which applications pose a potential risk to the public, (b) inspection and monitoring for anchors posing a potential risk, and (c) retrofit/repair suggestions for anchors posing a potential risk; and (5) provide draft language for addressing the use of epoxy adhesive anchors in the AASTHO LRFD Bridge Design Specification.</font></div>

Language

  • English

Project

  • Status: Completed
  • Funding: $500000.00
  • Contract Numbers:

    Project 4-37

  • Sponsor Organizations:

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590

    American Association of State Highway and Transportation Officials (AASHTO)

    444 North Capitol Street, NW
    Washington, DC  United States  20001

    National Cooperative Highway Research Program

    Transportation Research Board
    500 Fifth Street, NW
    Washington, DC  United States  20001
  • Project Managers:

    Harrigan, Edward

  • Performing Organizations:

    University of Florida, Gainsville

    339 Weil Hall
    Gainsville, FL  United States  32611
  • Principal Investigators:

    Cook, Ronald

  • Start Date: 20090710
  • Expected Completion Date: 0
  • Actual Completion Date: 20130731
  • Source Data: RiP Project 17900

Subject/Index Terms

Filing Info

  • Accession Number: 01464487
  • Record Type: Research project
  • Source Agency: National Cooperative Highway Research Program
  • Contract Numbers: Project 4-37
  • Files: TRB, RiP, USDOT
  • Created Date: Jan 3 2013 2:43PM