Rationale

It is proposed to replace the method of yield strength measurement at 1.0% elongation under load (EUL) with the 0.2% offset method. The elongation under load method was a practical necessity in an earlier, more technologically limited era. With the widespread use of software to automatically generate the test curve, there is no longer a need for utilizing the elongation under load method to determine the yield strength consistently and efficiently. The 0.2% offset method has been used in a variety of products and industries across a wide range of applications and specifications, including in recent revisions to ASTM specifications for steel reinforcement (specifically, reinforcing bar and WWR). Data analysis has indicated that utilizing the 0.2% offset method to determine yield strength for A416 strand results in a value comparable to, or in some cases, slightly (1 – 2%) above the value obtained by the 1.0% EUL method. Additionally, as no changes to strand dimensional or minimum breaking strength requirements are proposed, these slight updates to the yield strength measurement technique are not anticipated to result in any substantive changes to the product being supplied to the prestressing industry. Consequently, the minimum values in Table 2 are not proposed for revision.