Phase and Widening Construction of Steel Bridges

Phase construction is used to maintain traffic without interruption and generally refers to sequenced construction where a portion of the bridge is under construction while the remainder continues to carry traffic. The method typically results in two separate structures, or phases, that must then be joined. An elevation difference may exist between construction phases due to sources such as different creep and shrinkage deflection in phases and construction errors. The elevation gap may lead to some issues mainly related to fitting the cross-frames. The objectives of this research are to determine the role and influence of the cross-frames between construction phases on closure pour region performance in steel I-girder bridges that use phase construction. Alternative cross-frame configurations between construction phases are investigated as well as the effect that traffic-induced vibrations have on the quality of closure pour concrete. A parametric study was conducted considering: girder spacing, deck thickness, girder depth, phase configuration, and cross-frame spacing. The results indicate that total elimination of cross-frames between construction phases increases the maximum live load distribution factor of girders adjacent to closure pour by up to 14%, and deck transverse moment in closure region increases up to 75%. Use of horizontal struts between the phases provided performance similar to the use of full cross-frames and is an attractive alternative. The axial loads in the horizontal struts are similar to the corresponding component of the full cross-frame. Design provisions and recommendations are developed for using either alternative. A literature review on the effect of traffic-induced vibration produced conflicting results, and the topic will require further research.


  • English

Media Info

  • Media Type: Digital/other
  • Edition: Draft Final Report
  • Features: Appendices; Figures; Photos; References; Tables;
  • Pagination: 173p

Subject/Index Terms

Filing Info

  • Accession Number: 01532534
  • Record Type: Publication
  • Contract Numbers: BDK80-977-28
  • Created Date: Jul 25 2014 12:56PM