THE ROLE OF POLYETHYLENE DUCT CRACKING IN FAILURE OF POST TENSIONING CABLES IN FLORIDA SEGMENTED BRIDGES

During the past 20-plus years, designs based on the post-tension segmental box concept have evolved to become a predominant form of bridge construction. Critical to safety and longevity of such structures is the integrity of post-tensioning tendons; however, during the past five years, instances of tendon deterioration and failure have been disclosed on several Florida bridges. The underlying mechanism has been diagnosed as strand corrosion at grout voids in which bleed water accumulated. Cracking of high-density polyethylene (HDPE) ducts within which the grouted stands reside has also been disclosed; and while none of the failures to-date has been related to this cracking, left unaddressed, access of moisture, chlorides, and oxygen to the strands will invariably result in corrosion on the long term. For the purpose of (1) assessing the cause(s) and mechanism(s) of this HDPE duct cracking, (2) developing performance based assessment tests, and (3) proposing a standard for HDPE ducts employed in Florida bridges, a research project commenced in 2002 that involved investigators at both Florida Atlantic and Drexel Universities. The project consisted of 6 tasks: (1) acquisition of new and in-service polyethylene (PE) cable duct samples; (2) evaluation of material properties of retrieved and new duct samples; (3) evaluation of duct cracking mechanism; (4) evaluation of pipe stress crack resistance (SCR) using performance tests; (5) assessment of current material specifications for smooth PE duct; and (6) experimental and analytical modeling of tendon duct cracking.

• Corporate Authors:

  Florida Department of Transportation

  605 Suwannee Street
  Tallahassee, FL  United States  32399-0450

  Florida Atlantic University, Boca Raton

  Department of Civil Engineering, 777 Glades Road
  Boca Raton, FL  United States  33431
• Authors:
  • Hartt, W H
  • Suarez, J
  • David, F
  • Hsuan, G
  • Zhang, Jianping
• Publication Date: 2005-1-20

Language

• English

Media Info

• Features: Appendices; Figures; References; Tables;
• Pagination: 167 p.

Subject/Index Terms

• TRT Terms: Bridges; Cables; Cracking; Deterioration; Ducts; Durability; Evaluation; Failure; Materials; Performance; Posttensioning; Properties of materials; Safety; Segmental construction; Specifications; Stresses; Tendons (Materials); Tests
• Uncontrolled Terms: Polyethylene
• Geographic Terms: Florida
• Subject Areas: Bridges and other structures; Design; Highways; Materials; Safety and Human Factors; I24: Design of Bridges and Retaining Walls;

Filing Info

• Accession Number: 00988048
• Record Type: Publication
• Report/Paper Numbers: BD220
• Files: TRIS, STATEDOT
• Created Date: Mar 6 2005 12:00AM