ASTM A615

The material standard for plain and deformed carbon-steel bars for concrete reinforcement — the grades, the deformation pattern, and the chemical and mechanical requirements a bar has to meet. It defines what the bar is.

How much of it a member needs, and how it is lapped, bent and covered, is the structural design code's question. Weldability is deliberately not among its requirements: a bar meeting this standard is not certified as weldable, which is why welded splices call for a different specification.

Grade is not interchangeable. A higher grade bar substituted for a lower one changes the development and lap lengths the design assumed, and can make a section less ductile rather than stronger.

Bar size is read from the designation, and for the smaller bars it is arithmetic: an inch-pound bar number is the nominal diameter in eighths of an inch, so a #5 is five eighths and a #8 is one inch. Above #8 the relationship stops — a #9 is about 1.128 in, sized to match a one-square-inch area rather than a round diameter.

Grade is the minimum yield in thousands of pounds per square inch, which is why Grade 60 means 60,000 psi and not a sequence number. The grades in common use sit at 40, 60, 80 and 100, and the higher two exist mainly to reduce congestion where a section cannot hold the bars a lower grade would need.

The deformations are not decoration. The ribs are what transfers force between bar and concrete, and a plain round bar of the same steel develops a fraction of the bond — which is why the deformation pattern is a requirement of the standard rather than a manufacturing detail.

Identification is rolled into the bar itself: producer, size, bar type and grade, as marks a person can read on site after the delivery note has gone. It is the only way to tell what is lying on the ground once the bundles are broken.

Epoxy-coated, galvanised, low-alloy and stainless reinforcement are each a different specification. A bar meeting this one is plain carbon steel and nothing else is implied about its corrosion performance.

Obtained from ASTM International. What ASTM publishes

This site holds no edition list for ASTM A615, so a citation here names ASTM A615 rather than a year. The publisher above has the current designation.