Evaluation of the Use of Link Slabs in Bridge Projects, TR-701

Link slabs have been gaining some attention in the bridge engineering community lately. The basic link slab concept is to add/include a thin slab at the ends of the decks of two adjacent spans that allow the spans in a multi-span bridge to act as though they were simply-supported but in absence of a (problematic) joint. There appear to be two most promising applications for link slabs: (1) removing deck joints from existing bridges and (2) eliminating the use of joints in new prefabricated element bridges (known commonly as accelerated bridge construction) that require multiple spans. To be successful, a link slab must allow the ends of the adjacent spans to both rotate and displace as if the attached members were simply supported. The goal of this multipart project is to develop design details and evaluate the behavior of link slabs in new and existing bridges. The work to be funded by the Iowa Highway Research Board will focus on the use of link slabs in rehabilitation projects. The complementary/matching project will focus on the use of link slabs in accelerated bridge construction projects. Both projects will leverage information learned regarding material selection/design as well as the behavior of specific connection details. The objective of the Iowa Highway Research Board project is to evaluate the behavior of link slabs in a bridge scheduled for rehabilitation in the summer of 2016. One major advancement in increasing the service life of our nation's bridges has been related to the elimination of deck joints. In the case of the Iowa DOT, the use of integral abutments has been just one way of reducing the number of deck joints. Unfortunately, there are a very large number of bridges on the system that were designed before current joint elimination philosophies became mainstream. These existing joints deteriorate rapidly and require major maintenance efforts. In addition to the joint, the leakage of deicing materials on the end of prestressed girders and the subsequent deterioration is an ongoing problem. One method of addressing this issue that has been receiving notable national interest involves the use of so-called link slabs to remove deck joints from the structural systems. These link slabs are used to connect adjacent spans where no previous connecting elements existed. Despite the great potential, the use of link slabs to eliminate deck joints has only been explored to a limited extent because of multiple questions and concerns including those associated with thermal movements. Even more, the existing studies are not comprehensive and may have drawn conclusions that are not widely applicable [l-8] or are based upon a very limited set of assumptions. A bridge located in Benton County on Iowa 101 over the Cedar River in the Town of Vinton is scheduled to undergo a significant rehabilitation effort in the next 6-18 months. The existing bridge is a nine span bridge with expansion piers located at piers 3 and 6. Outwardly this bridge is a good candidate for deck joint elimination using link slabs. However, questions remain regarding how the bridge would behave under thermal load effects. In addition, the short- and long-term performance of the bridge after the installation of link slabs is of interest. As this is a typical bridge in the State of Iowa approaching the need for major maintenance, the outcome of this study is expected to provide invaluable information to utilize this innovative solution for a number of similar bridges that are in need of maintenance, particularly at their joints. Hence, the ultimate goal of the work proposed herein is to evaluate the use of link slabs in rehabilitation projects aimed at removing deck joints.

    Language

    • English

    Project

    • Status: Active
    • Funding: $69443
    • Contract Numbers:

      TR-701

      ISU proposal 134470

      Add 566

    • Sponsor Organizations:

      Iowa Department of Transportation

      800 Lincoln Way
      Ames, IA  United States  50010

      Iowa Highway Research Board

      Iowa Department of Transportation
      800 Lincoln Way
      Ames, IA  United States  50010
    • Managing Organizations:

      Iowa Department of Transportation

      800 Lincoln Way
      Ames, IA  United States  50010
    • Project Managers:

      Goetz, Vanessa

    • Performing Organizations:

      Iowa State University, Ames

      Institute for Transportation
      2711 South Loop Drive, Suite 4700
      Ames, Iowa  United States  50010-8664

      Iowa State University

      Bridge Engineering Center
      2711 South Loop Drive, Suite 4700
      Ames, Iowa  United States  50010-8664

      Iowa State University

      National Center for Wood Transportation Structures
      2711 South Loop Drive, Suite 4700
      Ames, Iowa  United States  50010-8664
    • Principal Investigators:

      Phares, Brent

      Hosteng, Travis

      Shafei, Behrouz

    • Start Date: 20160307
    • Expected Completion Date: 20181231
    • Actual Completion Date: 0
    • Source Data: TR-701; Addendum 566

    Subject/Index Terms

    Filing Info

    • Accession Number: 01593419
    • Record Type: Research project
    • Source Agency: Iowa Department of Transportation
    • Contract Numbers: TR-701, ISU proposal 134470, Add 566
    • Files: RiP, STATEDOT
    • Created Date: Mar 10 2016 10:19AM