Field verification for the effectiveness of continuity diaphragms for skewed continuous P/C P/S concrete girder bridges.

Details

• Creators:
  Saber, Aziz ; Mothukuri, Ajay K. ; Arasangi, Prashant
• Corporate Creators:
  Louisiana Transportation Research Center
• Corporate Contributors:
  Louisiana. Dept. of Transportation and Development
• Subject/TRT Terms:
  • Diaphragms (Engineering)
  • Prestressed concrete bridges
  • Continuous girder bridges
  • Testing
  • Diaphragms (Structural engineering)--Testing
  • Prestressed concrete bridges--Testing
  • Continuous bridges.
• Publication/ Report Number:
  FHWA/LA.09/440
• Resource Type:
  Tech Report
• Geographical Coverage:
  Louisiana
• Edition:
  Final report; April 2006-March 2008.
• Corporate Publisher:
  Louisiana Transportation Research Center
• Abstract:
  The research presented herein describes the field verification for the effectiveness of continuity diaphragms for ; skewed continuous precast, prestressed, concrete girder bridges. The objectives of this research are (1) to perform ; field load testing on the Burlington Northern Santa Fe (BNSF) overpass and compare measured strains with those ; determined through the theoretical analyses and (2) to study the effects of continuity diaphragms on stresses and ; deflections from truck loading on bridge deck slab and bridge girders. ; The current design concept of continuity diaphragms was examined to determine the effectiveness of the ; diaphragms in skewed bridges. The bridge parameters that were considered include skew angle, length of the ; span, beam spacing, the ratio of beam spacing to span (aspect ratio), and the ratio of girder stiffness to that of the ; slab. A prestressed concrete bridge with continuity diaphragms and a skewed angle of 48° was selected by a team ; of engineers from the Louisiana Department of Transportation and Development (LADOTD), the Louisiana ; Transportation Research Center (LTRC), the Federal Highway Agency (FHWA). ; The BNSF Overpass Bridge is located on US-90 in Jennings, Louisiana. The field verification was performed ; using a comprehensive instrumentation plan and live load tests as described in this report. The field and ; theoretical results from this study provided a fundamental understanding of the load transfer mechanism through ; these diaphragms of skewed, continuous span bridges. The findings in this study on stresses, strains, and ; deflections in the bridge deck and girders indicated that the effects of the continuity diaphragms on skewed ; continuous span precast prestressed concrete girder bridges were negligible. The results presented in this report ; also confirmed the theoretical findings published in LTRC Report 383 titled “Continuity Diaphragm for Skewed ; Continuous Span Precast Prestressed Concrete Girder Bridges.” Continuity diaphragms used in prestressed ; concrete girder bridges on skewed bents provided additional redundancy in the bridge but caused difficulties in ; detailing and construction. As the skew angle increases or the girder spacing decreases, the construction becomes ; more difficult and the effectiveness of the diaphragms becomes questionable. It is also recommended that the use ; of continuity diaphragms be evaluated based on the need for the enhanced structural redundancy, the reduced ; expansion joint installation and maintenance costs, and the associated construction difficulties and costs. The ; outcome of this research will reduce the construction and maintenance costs of bridges throughout Louisiana and ; the United States.
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• Format:
  PDF
• Funding:
  LTRC Project No. 06-3ST ; State Project No. 736-99-1373
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/18254/dot_18254_DS1.pdf
• File Type:
  [PDF - 5.22 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:b92c6b290ba0e63a67ae2342d51a99b2656506e3dbd5987dfc707c907bccdeb1