ULTIMATE STRENGTH OF BEAMS REINFORCED WITH STEEL HAVING NO DEFINITE YIELD POINT

Experimental evidence is presented on the conservative nature of the provisions of the Building Code (ACI 318-71) in predicting the ultimate strengths of beams reinforced with steel with no well defined yield point. Tests to failure were conducted on a total of 16 beams of various percentages of reinforcement. Eight of the beams were reinforced with high strength steel with a sharply defined yield point, and the others were reinforced with steel with no definite yield. A general theoretical method of calculating ultimate beam strength, for which no limiting strain criterion was involved, was used to corroborate experimental results. A Code modification which accounts for the strength increases realized in tests of beams reinforced with steel with no definite yield was developed. The Code was modified by extending the assumed concrete failure strain to 0.0004 and by using the steel stress corresponding to a strain of 0.0005 rather than 0.0035 on the actual stress-strain curve. Predictions according to the modification are most accurate at 75 percent of the balanced reinforcement ratio and conservative for lower reinforcement ratios. /Author/

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  • Corporate Authors:

    American Concrete Institute

    P.O. Box 19150, Redford Station, 22400 Seven Mile Road
    Detroit, MI  United States  48219
  • Authors:
    • Heimdahl, P D
    • Bianchini, A C
  • Publication Date: 1974-12

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Filing Info

  • Accession Number: 00082864
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Mar 26 1975 12:00AM