RELAXATION LOSSES IN STRESS-RELIEVED SPECIAL GRADE PRESTRESSING STRANDS

A PRELIMINARY EVALUATION OF RELAXATION LOSSES BASED ON TEST DATA OVER A PERIOD OF 444 DAYS IS REPORTED. FORTY SPECIMENS OF THE SEVEN-WIRE STRESS-RELIEVED STRANDS OF THE SPECIAL GRADE (270 K) WERE TESTED UNDER A CONSTANT-LENGTH CONDITION. THE PRIMARY CONTROLLED VARIABLES ARE STRAND SIZE, MANUFACTURER, AND INITIAL STRESS LEVEL. EXPRESSIONS FOR RELAXATION LOSS ARE DEVELOPED IN TERMS OF TIME AND INITIAL STRESS. TWO SETS OF EXPRESSIONS ARE SUGGESTED FOR THE ESTIMATION OF RELAXATION LOSS OF AN INITIAL PERIOD UP TO APPROXIMATELY 500 DAYS. A SEPARATE, SIMPLIFIED EXPRESSION IS PROPOSED FOR LONG-TERM PROJECTION OF THE TOTAL RELAXATION LOSS AT THE END OF FIFTY YEARS. ALSO INCLUDED IS A REVIEW OF PREVIOUS RESEARCH ON THIS SUBJECT AND A SUMMARY OF THE RELEVANT PROVISIONS IN SEVERAL FOREIGN AS WELL AS UNITED STATES DESIGN CODES. /AUTHOR/

  • Supplemental Notes:
    • Rept No 339.5, 123 PP, 26 FIG, 12 TAB, 32 REF, 3 APP
  • Corporate Authors:

    Lehigh University

    Fritz Engineering Laboratory
    Bethlehem, PA  United States  18015
  • Authors:
    • Batal, R J
    • Huang, T
  • Publication Date: 1971-4

Subject/Index Terms

Filing Info

  • Accession Number: 00209496
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Sep 6 1971 12:00AM