STUDIES OF COMPRESSIVE STRESS DISTRIBUTION IN SIMPLY REINFORCED CONCRETE NEAR THE POINT OF FAILURE

PILOT STUDIES HAVE BEEN MADE IN THE ENGINEERING EXPERIMENT STATION OF THE OHIO STATE UNIVERSITY USING A 6- BY 6- BY 0.66-IN. PIECE OF SPECIAL OPTICAL GLASS IN THE COMPRESSIVE AREA OF A 6 BY 12 IN. BY 15-FT. LONG HEAVILY REINFORCED CONCRETE BEAM RESTING ON SUPPORTS 12 FT. APART AND LOADED AT THE THIRD POINTS. THE GLASS IS SET IN THE COMPRESSIVE REGION OF THE MIDDLE OF THE LENGTH OF THE BEAM WHICH IS IN THE REGION OF NO SHEAR. THE PRESSURE FROM THE CONCRETE TO THE GLASS CAUSES STRAIN IN THE GLASS PROPORTIONAL TO THE PRESSURE. PHOTOELASTIC PHOTOGRAPHS GIVE INFORMATION FROM WHICH MAY BE DETERMINED THE AVERAGE COMPRESSIVE STRESS AT ANY DISTANCE FROM THE NEUTRAL AXIS. THE STRESS DISTRIBUTION THUS FOUND VARIES WITH THE MOISTURE VARIATION IN THE BEAM AND WITH THE VARIATION IN QUALITY OF THE CONCRETE AT DIFFERENT DEPTHS IN THE BEAM. IN GENERAL THE STRESS DISTRIBUTION MAY, BUT SELDOM DOES, FOLLOW A STRAIGHT LINE VARIATION. THE COMPRESSIVE STRESS IN THE EXTREME FIBER IS USUALLY SEVERAL HUNDRED POUNDS PER SQUARE INCH LESS IN INTENSITY THAN THE MAXIMUM COMPRESSIVE STRESS. INDICATIONS ARE THAT VARIATIONS IN MOISTURE AND HUMIDITY CONDITIONS AT THE DIFFERENT LAYERS GREATLY AFFECT THE STRESS DISTRIBUTION. THE CHARACTER OF POISSON'S RATIO IN THE VARIOUS LEVELS OF THE COMPRESSIVE REGION IS BEING OBSERVED. THERE IS ALSO A POSSIBLE INTERACTION BETWEEN THE GLASS INSERT AND THE CONCRETE WHICH MIGHT RESULT IN TENSION IN THE GLASS NORMAL TO THE DIRECTION OF THE BEAM AND TO THE DIRECTION OF POLARIZED LIGHT RAYS. /AUTHOR/

  • Supplemental Notes:
    • Vol 30, pp 114-125, 2 FIG, 9 PHOT
  • Authors:
    • Herr, L A
    • Vandegrift, L E
  • Publication Date: 1951

Media Info

  • Monograph Title: Proceedings of the Thirtieth Annual Meeting of the Highway Research Board Held at Washington, D.C., January 9-12, 1951
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00209439
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Jul 25 1971 12:00AM