Instrumentation and Monitoring the Performance of the FRP Shear Strengthening of the Salt Lake Boulevard Bridge

The Salt Lake Boulevard Bridge over Halawa Stream is a 3-span,continuous, prestressed concrete girder bridge. The 150-ft long, 100-ft wide bridge carries six lanes of heavy traffic. It has been determined that the shear capacity of some girders is inadequate. Furthermore, visual inspection has revealed that 16-girders have hairline diagonal shear cracks near the supports. These shear cracks are potentially quite serious. As a result, the City and County of Honolulu plans to strengthen the girders in shear. Although a specific strengthening system has not yet been selected, an FRP composite system appears to be the best alternative. It is anticipated that a strengthening system will be selected in the first half of 2003. If an FRP system is chosen, the principal investigators propose herein to instrument the FRP to measure its effectiveness under the dynamic traffic loads. Of particular interest is the possible delamination over extended periods caused by the dynamic loading and the resulting strain concentration as a result of movement of the existing cracks. We intend to monitor the performance of the FRP over several years. Should delamination occur, proper anchoring of the FRP, especially around reentrant corners and at the top and bottom, will be critical to its effectiveness. We propose to embed high fidelity, fiber optic sensors in the FRP layers as they are applied to the bridge. The shear strains in the girders will be quite small, and electrical resistance strain gages are inadequate to measure the strain with sufficient accuracy. High fidelity, fiber optic sensors, on the other hand, can measure very small strains. Sensors will be located both on the crack and above and below the crack. Measuring strains throughout the depth of the girders will allow delamination to be detected. A remote data acquisition system will be used so that the strain data will be transmitted continuously to our laboratory. Some data will be processed in real time and made available on a web site, so that authorized users, such as the city and state transportation departments, can observe the tests in real time. Finite element analysis of both uncracked and cracked, reinforced sections will be carried out to determine the theoretical shear strain distribution in the AASHTO-shaped girders. These predictions help in the placement of the strain gages. They will also be compared to the measured data.

    Language

    • English

    Project

    • Status: Active
    • Funding: $360886.00
    • Contract Numbers:

      51077

      HWY-L-2003-04

    • Sponsor Organizations:

      Federal Highway Administration

      300 Ala Moana Boulevard
      Honolulu, HI  United States  96850

      Hawaii Department of Transportation

      869 Punchbowl Street
      Honolulu, HI  United States  96813-5097
    • Project Managers:

      Santo, Paul

    • Performing Organizations:

      University of Hawaii, Manoa

      College of Engineering, Department of Civil and Environmental Engineering
      2540 Dole Street, Holmes Hall 383
      Honolulu, HI  United States  96822
    • Principal Investigators:

      Riggs, H

    • Start Date: 20031101
    • Expected Completion Date: 0
    • Actual Completion Date: 20081031
    • Source Data: RiP Project 12785

    Subject/Index Terms

    Filing Info

    • Accession Number: 01460463
    • Record Type: Research project
    • Source Agency: Hawaii Department of Transportation
    • Contract Numbers: 51077, HWY-L-2003-04
    • Files: RiP, USDOT, STATEDOT
    • Created Date: Jan 3 2013 1:25PM