MEASUREMENT OF DEVELOPMENT LENGTH OF 0.5-INCH AND 0.6-INCH DIAMETER PRESTRESSING STRAND IN FULLY BONDED CONCRETE BEAMS. INTERIM REPORT

This report focuses on determining the development length of 0.5-inch and 0.6-inch prestressing strands in fully bonded beams. I-shaped beams were used and made to resemble an AASHTO section complete with a composite deck. Nineteen development length tests were performed on the beams, which were loaded statically in flexure until failure. Flexural failures typically developed their ultimate flexural capacity, then experienced large deformations (ductility) before failing by yielding of the strands and crushing of the concrete. Bond failures were characterized by general slip of the strand through the specimen and gross displacements of the strand relative to the concrete (end slip). In most cases, bond failures were accompanied by brittle shear failures. These bond/shear failures resulted in sudden and total collapse of the beam, with little or no warning. From the test results, the embedment length was plotted versus the mode of failure. Development length is defined by the boundary length between flexural failure and bond failure. Overall, the test results were extremely well behaved, with good correlation between the different tests. Clear definitions of the development lengths were obtainable. It was concluded that: (1) the development lengths for 0.5-inch and 0.6-inch strands are adequately described by current AASHTO code provisions; and (2) development length for the 0.5-inch strand is approximately 72 inches, while that for the 0.6-inch strand is approximately 84 inches. These conclusions are correct for the cross section used. Furthermore, they may be considered conservative for development length if behavior is purely flexural (if web shear cracking is not present).

• Supplemental Notes:
  • Research study title: Influence of Debonding of Strands on Behavior of Composite Prestressed Concrete Bridge Girders.
• Corporate Authors:

  University of Texas, Austin

  Center for Transportation Research, 3208 Red River Street
  Austin, TX  United States  78705

  Texas Department of Transportation

  Transportation Planning Division, P.O. Box 5051
  Austin, TX  United States  78763

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Lutz, B A
  • Russell, B W
  • Burns, N H
• Publication Date: 1992-2

Language

• English

Media Info

• Features: Appendices; Figures; Photos; References; Tables;
• Pagination: 110 p.

Subject/Index Terms

• TRT Terms: Bonding; Deformation; Failure; Flexural strength; I beams; Laboratory tests; Prestressing
• Uncontrolled Terms: Development length; Flexural failure; Prestressing strands
• Old TRIS Terms: Bond failure; Bonded beams; Shear failures; Test results
• Subject Areas: Bridges and other structures; Design; Highways; I24: Design of Bridges and Retaining Walls;

Filing Info

• Accession Number: 00625532
• Record Type: Publication
• Report/Paper Numbers: FHWA/TX-92+1210-3, Res Rept 1210-3, CTR 3-5-89/2-1210-3
• Contract Numbers: Study 3-5-89/2-1210
• Files: TRIS, USDOT, STATEDOT
• Created Date: Dec 16 1993 12:00AM