Title:
Raising the Grade
Author(s):
David P. Gustafson
Publication:
Concrete International
Volume:
32
Issue:
4
Appears on pages(s):
59-62
Keywords:
steel reinforcement, yield strength, earthquake resistance, constructibility
DOI:
Date:
4/1/2010
Abstract:
ASTM Subcommittee A01.05, Steel Reinforcement, has made a significant revision to A706/A706M "Standard Specification for Low-Alloy Steel Deformed and Plain Bars for Concrete Reinforcement." The specification was developed in the early 1970s in response to the structural engineering community’s requirements for steel reinforcing bars with controlled tensile properties for use in earthquake-resistant structures and restricted chemical composition for weldability. As of December, 2009, it includes requirements for bars with a minimum yield strength of 80 ksi (550 MPa) (designated as Grade 80 [550]). The increased yield strength was especially encouraged by structural engineers, bar producers, bar fabricators, and contractors from seismically active areas because higher strength bars can help reduce congestion of reinforcement and enhance constructibility, especially in earthquake-resistant structures.