AN APPROACH TO THE CONTROL OF FLEXURAL CRACKING IN REINFORCED CONCRETE

HIGH STRESS AT WORKING LOAD IN STRUCTURAL CONCRETE MEMBERS REINFORCED WITH HIGH STRENGTH STEEL RESULTS IN ELASTIC DEFORMATIONS WELL BEYOND THOSE REQUIRED FOR CRACKING OF CONCRETE. THE CONTROL OF THE WIDTH OF FLEXURAL CRACKS IS NECESSARY BOTH TO PRESERVE THE INITIAL APPEARANCE OF A STRUCTURE AND TO PROTECT THE REINFORCEMENT FROM CORROSION. A PROCEDURE THAT IS SIMPLE TO APPLY YET PREDICTS FLEXURAL CRACK WIDTHS WITH REASONABLE ACCURACY IS NEEDED FOR A DESIGN CRITERION. PREVIOUS THEORETICAL APPROACHES TO THE CRACKING PROBLEM DID NOT YIELD RESULTS READILY USABLE BY DESIGNERS. SIMILARLY, THE EFFECT ON FLEXURAL CRACKING OF SIMILITUDE BETWEEN LABORATORY SPECIMENS AND FULL SCALE MEMBERS WAS NOT CLEAR. IN THIS PAPER, AVAILABLE TEST DATA ARE EVALUATED TO DETERMINE THE EFFECTS OF SIMILITUDE, REINFORCING STEEL STRESS AND AREA OF CONCRETE ABOUT THE REINFORCING BAR. AN EXPRESSION IS PRESENTED FOR CALCULATING MAXIMUM CRACK WIDTH AT THE LEVEL OF THE REINFORCING STEEL CENTROID. EQUATIONS ARE PRESENTED FOR MAXIMUM CRACK WIDTH WHICH SATISFACTORILY REFLECT THE EFFECT OF SCALE. THIS STUDY INDICATES THAT CRACK WIDTH IS PROPORTIONAL TO THE SQUARE ROOT OF THE SCALE FACTOR OR FOURTH ROOT OF THE CONCRETE AREA SURROUNDING EACH BAR. /ACIJP/

• Corporate Authors:

  American Concrete Institute (ACI)

  38800 Country Club Drive
  Farmington Hills, MI  United States  48331
• Authors:
  • Kaar, P H
• Publication Date: 1968

Subject/Index Terms

• TRT Terms: Areas; Concrete; Concrete structures; Cracking; Flexure; High strength steel; Reinforced concrete; Reinforcing steel; Steel; Stresses; Width
• Uncontrolled Terms: Concrete cracking
• Subject Areas: Bridges and other structures; Highways; Materials;

Filing Info

• Accession Number: 00209300
• Record Type: Publication
• Source Agency: Am Concrete Inst Journal & Proceedings
• Report/Paper Numbers: Title No Sp 20-8
• Files: TRIS
• Created Date: Sep 28 1970 12:00AM