PRESTRESS LOSSES IN PRETENSIONED CONCRETE STRUCTURAL MEMBERS

THIS REPORT CONTAINS THE RESULTS OF A COMPREHENSIVE STUDY ON PRESTRESS LOSSES IN PRETENSIONED CONCRETE STRUCTURAL MEMBERS. THE EXPERIMENTAL PROGRAM INCLUDED A PRELIMINARY COMPARISON OF CHARACTERISTICS OF SEVERAL CONCRETE MIXTURES REGULARLY USED IN PENNSYLVANIA, AN EXTENSIVE STUDY OF THE ELASTIC, CREEP AND SHRINKAGE BEHAVIOR OF TWO OF THESE CONCRETES REPRESENTING RESPECTIVELY THE UPPER AND THE LOWER BOUNDS, AND A STUDY OF THE RELAXATION CHARACTERISTICS OF PRESTRESSING STRANDS. STRESS-STRAIN-TIME RELATIONSHIPS WERE DEVELOPED EMPIRICALLY FOR BOTH CONCRETE AND STEEL, DEPICITING THEIR ELASTIC, CREEP, SHRINKAGE AND RELAXATION PROPERTIES. A BASIC PROCEDURE FOR THE EVALUATION OF STRESS CONDITIONS IN A PRETENSIONED MEMBER WAS ESTABLISHED BY LINKING THESE STRESS-STRAIN-TIME RELATIONSHIPS BY CONDITIONS OF COMPATIBILITY AND EQUILIBRIUM. A PRACTICAL PROCEDURE IS RECOMMENDED FOR PREDICTING PRESTRESS LOSSES AT VARIOUS TIMES, BASED ON AN EXTENSIVE PARAMETRIC STUDY OF THE BASIC PROCEDURE. ATTENTION IS FOCUSED ON PRESTRESS LOSSES AT THE TWO CRUCIAL DESIGN STAGES, NAMELY, IMMEDIATELY UPON TRANSFER AND AT THE END OF SERVICE LIFE. EFFECT OF APPLIED LOAD IS FULLY TAKEN INTO CONSIDERATION. EXAMPLES OF APPLICATION OF THE RECOMMENDED PROCEDURE AND COMPARISONS WITH OTHER METHODS ARE GIVEN.

  • Supplemental Notes:
    • Contract PA DOT RES PRJ 66-17
  • Corporate Authors:

    Lehigh University

    Fritz Engineering Laboratory
    Bethlehem, PA  United States  18015
  • Authors:
    • Huang, T
  • Publication Date: 1973-8

Media Info

  • Pagination: 143 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00208092
  • Record Type: Publication
  • Source Agency: Federal Highway Administration
  • Report/Paper Numbers: Final Rept
  • Files: TRIS, USDOT
  • Created Date: Apr 20 1974 12:00AM