STRESSES IN CONCRETE PAVEMENT SLABS

LOADS HAVE BEEN APPLIED TO EXPERIMENTAL SLABS AT A CORNER AND THE TENSILE STRAINS IN THE TOP SURFACE OF THE SLAB HAVE BEEN MEASURED BY MEANS OF OPTICAL LEVER EXTENSOMETERS. THE STRAIN MEASUREMENTS, TOGETHER WITH OBSERVATION OF THE SHAPE OF STRUCTURAL CORNER BREAKS, HAVE LED TO A NEW HYPOTHESIS RELATIVE TO THE DISTRIBUTION OF STRESS, OR THE LOCUS OF MAXIMUM MOMENT IS A CURVED LINE WHICH MAY LIE ANYWHERE BETWEEN A CIRCULAR CURVE HAVING THE CORNER OF THE SLAB AS A CENTER AND A LINE TANGENT TO THIS CURVE AT RIGHT ANGLES TO THE CORNER BISECTOR. THE MOMENT IS NON-UNIFORMLY DISTRIBUTED ALONG THIS PATH, BEING GREATER NEAR THE BISECTOR THAN AT THE EDGES OF THE SLAB. THE FACTORS WHICH CONTROL THE VARIATIONS IN SHAPE OF THE LOCUS OF MAXIMUM MOMENT BETWEEN THE DESCRIBED LIMITS ARE NOT DISCENIBLE. SINCE THE GREATEST STRESS IN THE SLAB UNDER THIS HYPOTHESIS WILL OCCUR WHEN THE LOCUS IS A CIRCULAR CURVE AND THE LEAST STRESS WILL OCCUR WHEN IT IS A STRAIGHT LINE NORMAL TO THE BISECTOR, ANALYSES INCORPORATING THESE LIMITING CASES ARE INTRODUCED AND TWO EXPRESSIONS, ONE FOR THE MAXIMUM AND THE OTHER FOR THE MINIMUM PROBABLY TENSILE STRESSES ALONG THE CORNER BISECTOR, AE DERIVED. THESE EQUATIONS, WHEN EVALUATED WITH CONSTANTS APPLICABLE TO THE FIRST EXPERIMENTAL SLAB STUDIED, DEFINE TWO STRESS CURVES, ONE OF WHICH IS ABOUT 50 PERCENT GREATER THAN THE OTHER. IN GENERAL, THE MEASURED STRESSES IN THIS SLAB LIE BETWEEN THESE LIMITING CURVES AND ARE NEARER THE CURVE OF MAXIMUM PROBABLY STRESS. A COMPARISON BETWEEN BOTH THE MEASURED AND ANALYTICALLY DETERMINED STRESSES AND THOSE OBTAINED BY DR. WESTERGAARD'S ANALYSIS REVEALS SUBSTANTIAL AGREEMENT BETWEEN THEM AS TO THE DISTANCE FROM THE CORNER AT WHICH MAXIMUM STRESSES OCCUR. ALSO HIS CONCLUSION THAT THE MAGNITUDE OF SUBGRADE REACTION HAS RELATIVELY LITTLE EFFECT UPON STRESSES IS VERIFIED. THE EXPRESSION HERE DERIVED FOR MINIMUM PROBABLY STRESS COINCIDES WITH HIS EXPRESSION FOR MAXIMUM STRESS. THE STUDIES REVEAL THE NEED FOR FURTHER EXPERIMENTAL EVIDENCE RELATIVE TO THE RELATIONSHIP BETWEEN SUBGRADE REACTIONS AND DEFLECTIONS AND THE DISTRIBUTION OF DEFLECTIONS IN THE CORNER REGION OF SLABS. /AUTHOR/

  • Supplemental Notes:
    • Vol 15, pp 122-146, 20 FIG, 1 TAB
  • Authors:
    • Spangler, M G
  • Publication Date: 1936

Media Info

  • Monograph Title: Proceedings of the Fifteenth Annual Meeting of the Highway Research Board Held at Washington, D.C. December 4-6, 1935
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00207160
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Jun 11 1971 12:00AM