Mechanical strength variability of deformed reinforcing steel bars for concrete structures in Ethiopia

Abstract

The paper presents statistical analysis of mechanical strength and linear density properties of deformed reinforcing Grade 60 steel bars. Two different lots of samples are identified based on test years for the years 2015–2017 as Lot 1 and 2018–2020 as Lot 2. Yield strength (YS), tensile strength (TS), elongation, mass per length and characteristic ratio of TS and YS are analyzed for rebar diameters of 8, 10, 12 and 16 mm considering both lots. Mechanical and linear density properties are compared statistically using range, mean, standard deviation, coefficient of variance, skewness and kurtosis of the recorded sets of values. Moreover, the results of YS, TS and elongation are analyzed separately by one-way analysis of variance for both lots. The result shows that the aggregate mean values of YS, TS and elongation for Lot 1 and Lot 2 are 593.1 MPa, 701.1 MPa, 14.78%; and 572.5 MPa, 673.8 MPa, 15.47%, respectively. Even though there is a slight decrement in values of YS and TS and increment in elongation from Lot 1 to Lot 2, both lots exceeded values recommended by ASTM A615 standard. Furthermore, with 95% confidence interval, one-way analysis of variance showed that the aggregate data of rebars are dissimilar in terms of YS, TS and percentage elongation with figures showing decrement from Lot 1 to Lot 2.

Study of Effects of Lateral Confinement on Concrete Columns Reinforced With Tmt Bars

“…Considering these advantages, the use of TMT bars is increasing with time in other parts of the world [29]. A major concern in the developing world in this respect is the use of steel scrap and ingots in the manufacturing of steel bars which makes the mechanical properties of the manufactured rebars uncertain [33][34][35][36][37][38][39]. More often the bar yielding strength is so high (as compared to that assumed in the design based on the recommended strength by the rebar manufacturing standard) that it causes brittle failure in exural members [34].…”

Evaluation of quality defining attributes of reinforced cement concrete constructions using analytic hierarchy process

“…Reinforcement bars must meet specific criteria for ultimate and yield strength [15], carbon content, elongation value [16], and tensile strength. The minimum elongation value depends on the diameter and grade of reinforcement bars, with the minimum value between 10%-20%.…”