Effect of implementing lean-on bracing in skewed steel I-girder bridges.

Details

• Creators:
  Bechtel, Andrew
• Corporate Creators:
  The College of New Jersey
• Corporate Contributors:
  City University of New York. University Transportation Research Center
• Subject/TRT Terms:
  • Skew bridges
  • Girder bridges
  • Steel bridges
  • Bracing
  • Steel I-Girder
  • Bracing
  • Lean-on bracing
• Resource Type:
  Tech Report
• Geographical Coverage:
  New Jersey
• Corporate Publisher:
  City College of New York. University Transportation Research Center
• Abstract:
  Skew of the supports in steel I-girder bridges cause undesirable torsional effects, increase cross-frame forces, and generally increase the difficulty of designing and ; constructing a bridge. The girders experience differential deflections due to the skewed supports, and undesirable effects arise when the girders are linked transversely. ; Before the placement of the deck, the main method of linking the girders transversely is through the use of cross-frames. The cross-frames are designed to provide ; stability during construction and distribute transverse loads through the bridge girders; this is their primary role. Cross-frames also help control differential displacement ; during deck placement and distribute vertical loads in the bridge’s elastic and inelastic ranges. The cross-frames are not specifically designed for these tasks; these are the ; secondary roles of the cross-frames. Lean-On bracing has been proposed to reduce skew effects caused by traditional cross-frames. While having been shown to improve ; skew effects, the alternative cross-frame designs have not been evaluated on the effect they have on the cross-frames’ secondary roles. ; This paper describes a study of the effects Lean-On bracing has on the secondary roles of cross-frames. Three-dimensional Finite Element Models were used to perform a ; study involving changes in skew angle and cross-frame design. The rotation of the girders, maximum cross-frame stresses, load distribution, and differential displacement ; between the girders were used to characterize the behavior of the bridges. For the bridge type studied, the only major difference in performance was that the maximum ; cross-frame stresses were reduced for the bridges modeled with Lean-On bracing.
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• Format:
  PDF
• Funding:
  49198-21-27
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/31704/dot_31704_DS1.pdf
• File Type:
  [PDF - 1.90 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:f84064aa2852dca18139d82241537deb70a35a93dff676dfadd2e0563b422a38