Details:

Creators:
Trejo, David
Corporate Creators:
Texas Transportation Institute
Corporate Contributors:
Texas. Dept. of Transportation. Research and Technology Implementation Office
Subject/TRT Terms:
[+]
Air Content Concrete--Air Content--Texas Concrete Bridges Concrete Bridges--Inspection--Texas Concrete Bridges--Texas--Maintenance And Repair Post-tensioned Prestressed Concrete Construction--Texas Prestressed Concrete Bridges
Publication/ Report Number:
FHWA/TX-09/0-4588-1 Vol. 2
Resource Type:
Tech Report
Geographical Coverage:
Texas
Edition:
Technical report; Sept. 2003-Aug. 2008.
Abstract:
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, timevariant

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.


Format:
PDF
Funding:
Project 0-4588
Collection(s):
US Transportation Collection
Main Document Checksum:
[+]
urn:sha256:d20467a1a0c743f349c60483eb1cd03915c57e132130172fbc3e51fcd6c4e33d
Download URL:
https://rosap.ntl.bts.gov/view/dot/16990/dot_16990_DS1.pdf
File Type:

Supporting Files

• No Additional Files

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