Statistical Analysis of the Mechanical Properties and Weight of Reinforcing Bars

ii The variability of the mechanical properties and weight of steel reinforcing bars produced in the United States and Canada under ASTM A 615, A 616, and A 706 in 1997 is evaluated and expressions are developed to represent the probability distribution functions for yield and tensile strength. Thirty-four mills were invited to submit data on yield strength, tensile strength, elongation, and percent of nominal weight. Of these, 29 mills submitted data on a heat-by-heat basis, three mills provided average values (no data on a heat-by-heat basis), one mill provided data on “No Grade ” bars (these were not used in this analysis), and one mill did not respond to the request for data. A statistical analysis of bar properties is conducted. Trends in the data are evaluated based on grade, bar size, and production mill. Beta functions are developed to represent the probability distribution functions for yield and tensile strength for each bar size, grade, and steel type, as well as for all bars for each grade and steel type. The analyses show that less than 0.1 % of the steel heats failed to meet minimum AST