Effect of Voids in Grouted, Post-Tensioned Concrete Bridge Construction: Volume 2 – Inspection, Repair, Materials, and Risks

Post-tensioned (PT) bridges are major structures that carry significant traffic. These bridges are designed and constructed because they are economical for spanning long distances. In Texas, there are several signature PT bridges. In the late 1990s and early 2000s, several state highway agencies identified challenges with the PT structures: mainly corrosion of the PT strands. The Texas Department of Transportation (TxDOT) performed some comprehensive inspections of their PT bridges. A consultant’s report recommended that all ducts be re-grouted. However, the environment in Texas is very different than the environments in which the corrosion of the PT strands were observed. The objective of this research was to evaluate the corrosion activity of strands for PT structures and to correlate this corrosion activity with general environmental and void conditions. To achieve this objective, time-variant probabilistic models were developed to predict the tension capacity of PT strands subjected to different environmental and void conditions. Using these probabilistic models, time-variant structural reliability models were developed. The probability of failure of a simplified PT structure subjected to HS20 and HL93 loading conditions was assessed. Both flexural failure and serviceability were assessed. Results indicate that the presence of water and chlorides can lead to significant corrosion rates and failure is dependent on this corrosion activity and the number of strands exposed to these conditions. These results are presented in Volume 1 of this report. To assist TxDOT with developing a plan to mitigate this corrosion, studies were performed to assess repair grout materials, inspection methods, and repair methods. In addition, a general methodology is presented on optimizing repairs. These topics are presented in Volume 2 of this report. An Inspection and Repair Manual was also developed from this research and is presented in a separate report. Results indicate that TxDOT should prevent water and chlorides from infiltrating the tendons — this can be achieved in part by repairing drain lines, ducts, and protecting anchor heads as these conditions can lead to early failure of PT bridges. Recommendations on inspections, repairs, and materials are provided, however, further research on the potential formation of galvanic coupling of strands embedded in both existing and new repair grouts need to be assessed.

  • Record URL:
  • Supplemental Notes:
    • Project Title: Effect of Voids in Grouted, Post-Tensioned Concrete Bridge Construction. Report Date: February 2009; Published: Septemer 2009.
  • Corporate Authors:

    Texas Transportation Institute

    Texas A&M University System, 3135 TAMU
    College Station, TX  United States  77843-3135

    Texas Department of Transportation

    Research and Technology Implementation Office, P.O. Box 5080
    Austin, TX  United States  78763-5080

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Authors:
    • Trejo, David
    • Hueste, Mary Beth D
    • Gardoni, Paolo
    • Pillai, Radhakrishna G
    • Reinschmidt, Kenneth F
    • Im, Seok Been
    • Kataria, Suresh
    • Hurlebaus, Stefan
    • Gamble, Michael
    • Ngo, Thanh Tat
  • Publication Date: 2009-9

Language

  • English

Media Info

  • Media Type: Web
  • Edition: Technical Report
  • Features: Appendices; Figures; Photos; References; Tables;
  • Pagination: 342p

Subject/Index Terms

Filing Info

  • Accession Number: 01145970
  • Record Type: Publication
  • Report/Paper Numbers: FHWA/TX-09/0-4588-1 Vol. 2, Report 0-4588-1 Vol. 2
  • Contract Numbers: Project 0-4588
  • Files: TRIS, USDOT, STATEDOT
  • Created Date: Dec 9 2009 2:33PM