Headed Steel Bars for Concrete Reinforcement

A970/A970M-17: Standard Specification for Headed Steel Bars for Concrete Reinforcement

When designing and constructing robust concrete structures, the integrity of reinforcement anchorage is paramount. ASTM A970/A970M-17 provides the essential framework for specifying headed steel bars, a critical component for ensuring secure and reliable concrete reinforcement anchorage. This industry-leading standard offers engineers and fabricators a proven method for ensuring the quality and performance of these specialized reinforcing elements.

What is A970/A970M-17?

ASTM A970/A970M-17, the "Standard Specification for Headed Steel Bars for Concrete Reinforcement," establishes comprehensive requirements for deformed steel reinforcing bars with integral or attached heads. Developed by ASTM International, this standard ensures consistency in the manufacturing and performance of headed bars, which are crucial for load transfer and structural integrity in demanding concrete applications. Its primary purpose is to provide a reliable benchmark for materials, fabrication methods, and testing.

Scope & Purpose

This authoritative standard governs the material, manufacture, and testing of deformed steel reinforcing bars that have a head attached to one or both ends. It covers various methods of head attachment, including welding, hot forging, threaded connections, cold swaging, cold extrusion, and the use of ferrous filler materials. The specification outlines requirements for head dimensions and the impact of heads on bar deformations. However, it does not cover the structural design calculations or specific application guidelines for using headed bars within a concrete element, which are typically addressed by building codes and design standards like ACI 318.

Who Must Comply?

• • Primary audience: Structural Engineers, Civil Engineers, Materials Engineers, Quality Control Inspectors, and Steel Fabricators.
• • Industries affected: Construction, Civil Engineering, Steel Production and Fabrication.
• • Compliance nature: Primarily specified by purchasers for projects and adopted by manufacturers. It is often a contractual requirement rather than a direct regulatory mandate, though it underpins many building code requirements.
• • Enforcement: Compliance is typically verified through project specifications, third-party inspections, and quality assurance programs during fabrication and construction.

Key Requirements Overview

• • The standard requires that reinforcing bars used for headed bar production conform to specified ASTM standards for deformed bars, such as A615/A615M or A706/A706M, depending on the chosen fabrication method.
• • Manufacturers must ensure that the methods used to attach heads (e.g., welding, forging, swaging) meet the mechanical performance criteria outlined in the specification.
• • Key provisions include detailed requirements for head dimensions, material properties of the head (where applicable), and the integrity of the connection between the bar and the head.
• • Professionals must ensure that the headed bars, when tested according to referenced ASTM standards (like A370), meet the specified tensile strength, yield strength, and elongation requirements, demonstrating adequate anchorage capacity.
• • The specification also addresses packaging, marking, and loading to ensure product integrity during transit and storage.

Related Standards & References

A970/A970M-17 works in conjunction with several other ASTM standards. ASTM A370 (Test Methods and Definitions for Mechanical Testing of Steel Products) is