Maximum Crack Width in Reinforced Concrete Flexural Members

THE MAXIMUM CRACK WIDTH MEASUREMENTS FROM A NUMBER OF CRACK WIDTH INVESTIGATIONS WERE EXAMINED USING STATISTICAL METHODS. PREVIOUSLY PROPOSED EQUATIONS FOR MAXIMUM CRACK WIDTH WERE COMPARED AND NEW EQUATIONS WERE PROPOSED AS A RESULT OF THE ANALYSES. INTEREST IN CRACK WIDTHS IN FLEXURAL MEMBERS HAS BEEN STIMULATED BY THE TREND TO USE HIGH STRENGTH DEFORMED REINFORCING BARS. VARIOUS INVESTIGATIONS HAVE PRODUCED MUCH INFORMATION ABOUT THE WIDTH AND SPACING OF CRACKS. HOWEVER, DUE TO THE RELATIVELY LARGE SCATTER IN THE WIDTH OF THE LARGEST CRACKS, AND TO THE LARGE NUMBER OF INTERRELATED VARIABLES PRESENT IN REINFORCED CONCRETE BEAMS, AGREEMENT WAS LACKING AMONG THE INVESTIGATORS AS TO THE MOST PERTINENT VARIABLES INFLUENCING THE SIZE OF THE CRACKS. BY USING DATA FROM SIX DIFFERENT INVESTIGATIONS, THE SAMPLE WAS LARGE AND DIVERSE ENOUGH TO PERMIT RELIABLE STATISTICAL ANALYSES. THE MAXIMUM CRACK WIDTH MEASURED ON A BEAM AT A CERTAIN STEEL STRESS LEVEL REPRESENTED A STATISTICAL SAMPLE. IN THE COMPUTER INPUT, EACH SAMPLE WAS ACCOMPANIED BY ALL BEAM DETAILS THAT COULD INFLUENCE THE CRACK WIDTH.