Methods for strengthening reinforced concrete bridge girders containing poorly detailed flexural steel using near-surface mounted metallics.

Details

• Creators:
  Higgins, Christopher ; Amneus, Deanna ; Barker, Laura
• Corporate Creators:
  Oregon State University. School of Civil and Construction Engineering
• Corporate Contributors:
  United States. Federal Highway Administration
• Subject/TRT Terms:
  • Reinforced concrete bridges
  • Girders
  • Flexural strength
  • Bridge decks
  • Reinforcing bars
  • Strengthening (Maintenance)
  • Bridge anchorages
  • Deformation
• Publication/ Report Number:
  FHWA-OR-RD-16-02
• Resource Type:
  Tech Report
• Geographical Coverage:
  Oregon
• Corporate Publisher:
  Oregon. Dept. of Transportation. Research Section
• Abstract:
  Many older reinforced concrete deck girder (RCDG) bridges contain straight-bar terminations of flexural reinforcement in ; flexural tension zones without special detailing. Common bridge design practice of the 1950s did not consider the additional ; demands on the terminated bars from shear and flexure. Moreover, application of modern design code provisions and use of ; heavier trucks contribute to insufficient bridge load ratings when evaluating flexural anchorages in existing RCDG bridges. ; Replacement of bridges with poor ratings due to localized deficiencies is not economically feasible and thus strengthening ; methods are necessary. ; The goal of this research was to investigate methods for strengthening deficient flexural steel anchorages using ; supplemental surface bonded metallic reinforcing bars. Full-scale reinforced concrete girder specimens with typical vintage ; details and materials were used as test specimens. The specimens were constructed with flexural anchorage deficiencies by ; terminating some of the embedded flexural bars past a 45° preformed diagonal crack. The terminated bars had only one-third of the code-prescribed development length past the diagonal crack. ; A strengthening technique called near-surface mounting (NSM) was applied to the specimens. Two metallic materials were ; selected for the NSM reinforcement: titanium and stainless steel. These materials were chosen because of their high ; strength, ductility, environmental durability, and ability to form mechanical hooks at the ends of the bars. This study found ; that the NSM strengthening technique with metallic materials increased the deformation and load capacity of all ; specimens. In addition, a case study was performed to demonstrate the flexural strengthening for the Mosier Bridge ; overcrossing of I84 in Oregon. The case study demonstrated that the techniques and materials applied to the girder were ; able to achieve the required strength and provided good deformation capacity.
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• Format:
  PDF
• Funding:
  SPR 750
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/29161/dot_29161_DS1.pdf
• File Type:
  [PDF - 8.25 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:9bc38bf34c5b87d08a8753172f43b2ff7d9f43b6c05733ff36d8e843e78f49128b47ed82faf9314bbccbb686a02e705c91b92acd331160f7ea751873c9e7d552