Effect of voids in grouted, post-tensioned concrete bridge construction : volume 1--electrochemical testing and reliability assessment.

Details

• Creators:
  Trejo, David ; Hueste, Mary Beth D. ; Gardoni, Paolo
• Corporate Creators:
  Texas Transportation Institute
• Corporate Contributors:
  Texas. Dept. of Transportation. Research and Technology Implementation Office
• Subject/TRT Terms:
  Air Content Bridge Design Post-tensioned Prestressed Concrete Construction--Texas Concrete--Air Content--Texas Concrete Bridges--Texas--Design And Construction Prestressed Concrete Bridges
• Publication/ Report Number:
  FHWA/TX-09/0-4588-1 Vol. 1
• Resource Type:
  Tech Report
• Geographical Coverage:
  Texas
• Edition:
  Technical report; Sept. 2003-Aug. 2008.
• Corporate Publisher:
  Texas Transportation Institute
• Abstract:
  Post-tensioned (PT) bridges are major structures that carry significant traffic. PT bridges 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 its 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. Volume 1 of this report presents these results. 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 and 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 needs to be assessed.
  
  
• Format:
  PDF
• Funding:
  Project 0-4588
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:74cac3d0f4c6524bd090fa022a15a40a24a8d303c287c603dd2183dc7d6ce52bafd679cd7eb037b4659386b475d0a2c3aa30fc41033ab57505c21f0be3ee6d1d
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/16989/dot_16989_DS1.pdf
• File Type:
  [PDF - 6.66 MB ]