The study examines the use of embedded prestressing strand to develop positive moment continuity of prestressed, precast I-beam members. Bond of untensioned prestressing strands and connections utilizing untensioned strands were studied. Load determation and load embedment requirements of untensioned prestressing strand was studied. Three strand configurations were tested and evaluated: straight, frayed and bent 90 degrees over a reinforcing bar. Equations were developed which relate slip to applied steel stress for each configuration. Design equations were developed which relate the embedment length necessary to assure against general slip for a given steel stress. The influence of strand diameter, concrete strength, and containment reinforcing were found to be of little consequence. Six full-scale bent, untensioned strand connections were designed, fabricated and tested. The strength and deformation of the connections were related to the number and embedment length of the prestressing strand. The effects of standard diaphragm tie reinforcing was evaluated. A working stress design procedure with an ultimate strength check was developed for the connection. It was concluded that, using this procedure, untensioned prestressing strand can be designed to develop a satisfactory degree of positive moment continuity for precast, prestressed I-beam bridge super-structures. /FHWA/

  • Record URL:
  • Supplemental Notes:
    • In cooperation with the Department of Transportation, Federal Highway Administration. Sponsored by the Missouri State Highway Department.
  • Corporate Authors:

    University of Missouri, Columbia

    Department of Civil Engineering, 2509 Engineering Building East
    Columbia, MO  United States  65211

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590

    Mississippi State Highway Department

    P.O. Box 1850
    Jackson, MI  United States  39215
  • Authors:
    • Salmons, J R
  • Publication Date: 1974-11

Media Info

  • Pagination: 61 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00130570
  • Record Type: Publication
  • Source Agency: Federal Highway Administration
  • Report/Paper Numbers: FHWA-RD-77- 14 Final Rpt.
  • Contract Numbers: 72-7
  • Created Date: Mar 29 1976 12:00AM