Simple for Dead Continuous for Live (SDCL) Steel Girder Bridges with UHPC and GFRP

Steel girder construction can offer a competitive and efficient structural system option for bridges in terms of material costs and constructability. For multi-span bridges, the most structurally efficient approach has been to use continuous girders, with splice points near dead load inflection points. The construction implication of this design decision is that girder splices must be installed over active traffic lanes, or falsework must be provided under the splice location, which reduces the available traffic lanes. An alternative construction method was studied by Dr. Azizinamini, with support from the Nebraska Department of Roads (NDOR), and documented for NDOR Research Project Number P542 (Azizinamini et al., 2005a, 2005b). Dr. Azizinamini borrowed a concept commonly implemented for concrete girder construction: Simple for Dead, Continuous for Live (SDCL). SDCL offers several benefits over continuous construction. The immediately apparent benefit is the elimination of the splice over traffic lanes. Additionally, SDCL can offer material optimization. For continuous steel girders, the maximum flexural demands occur at the continuous supports, with compression at the bottom of the girder. For SDCL construction, peak moment demands are shifted to the positive moment region, where the structural material is more efficiently engaged with compression in the concrete deck and tension in the steel girder. Comparative moment diagrams for SDCL versus continuous structures are illustrated in from Ream and Beining (2014). The details developed by Dr. Azizinamini require substantial concrete diaphragms at the continuity locations. This research will investigate optimized construction methods for the diaphragm to provide comparable or superior constructability and structural performance, compared to existing SDCL for steel girder bridge details, when using ultra-high performance concrete (UHPC) at the girder continuity locations. Glass Fiber Reinforced Polymer {GFRP) has been studied as a viable alternative to steel reinforcing to reduce life cycle costs for bridge structures, especially decks. The material behavior is well documented for uses in conventional concrete, but has not yet been thoroughly studied for uses in UHPC. The combination of UHPC and GFRP can offer an essentially maintenance-free structural system, with negligible cracking in the UHPC, and non-corrosive glass-reinforced polymer at crossing reinforcing bridging to conventional concrete in decks. The development length of steel reinforcing is known to be much shorter than in conventional concrete (Graybeal, 2014). Lap splices on the order of 5 to 6 inches have been implemented in practice for steel in UHPC. The required development and lap splice lengths for GFRP have received only limited attention at this time. Additionally, the susceptibility of steel crossing reinforcing to corrosion at the cold joint between conventional concrete and UHPC requires that concrete surfaces be roughened before placing UHPC. This additional labor cost can potentially be avoided by using GFRP. The availability of Owens Corning as a local resource in the state of Nebraska, and the willingness on the part of their company to collaborate and donate materials and expertise, present opportunities that will be leveraged in the proposed research for the benefit of NDOT. The primary objectives of this research are to: (1) develop details to optimize SDCL steel girder structural design and construction for material and construction efficiency with UHPC; (2) identify available software tools for SDCL steel girder design and rating, and/or develop an action plan for modification to existing software, as applicable; and (3) characterize development behavior and required embedment lengths for full development of GFRP bars in UHPC.


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    • Status: Active
    • Funding: $132358
    • Sponsor Organizations:

      Nebraska Department of Transportation

      1500 Nebraska 2
      Lincoln, NE  United States  68502
    • Project Managers:

      Halsey, Lieska

    • Performing Organizations:

      University of Nebraska, Lincoln

      1400 R Street
      Lincoln, NE  United States  68588
    • Principal Investigators:

      Steelman, Joshua

    • Start Date: 20190701
    • Expected Completion Date: 20221231
    • Actual Completion Date: 0
    • USDOT Program: Transportation, Planning, Research, and Development

    Subject/Index Terms

    Filing Info

    • Accession Number: 01705856
    • Record Type: Research project
    • Source Agency: Nebraska Department of Transportation
    • Files: RIP, STATEDOT
    • Created Date: May 24 2019 8:52AM