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, DEPICTING 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. TWO ADDITIONAL REPORTS GENERATED BY THIS RESEARCH ARE: "RELAXATION BEHAVIOR OF PRESTRESSING STRANDS" (REPORT NO. 339.6) AND "ESTIMATION OF CONCRETE STRAINS AND PRESTRESS LOSSES IN PRETENSIONED MEMBERS" (REPORT NO. 339.7)

  • Supplemental Notes:
    • 4 APP
  • Corporate Authors:

    Lehigh University

    Bethlehem, PA  USA  18015
  • Authors:
    • Huang, T
  • Publication Date: 1973

Media Info

  • Features: Figures; References; Tables;
  • Pagination: 100 p.
  • Serial:
    • Issue Number: 339

Subject/Index Terms

Filing Info

  • Accession Number: 00210029
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Feb 12 1974 12:00AM