The Simpson Strong-Tie ATRM8-4 ATRM 1 in. x 48 in. All-Thread Rod, Grade 55 is a fully threaded steel rod engineered by Simpson Strong-Tie to serve as a tension transfer element in structural systems designed to resist seismic and wind forces. This all-thread rod delivers a continuous and reliable load path from roof to foundation, making it a trusted solution for shearwall overturning restraint within continuous rod tiedown systems and for uplift restraint in roof applications. Its versatility extends further to use as an adhesive anchor rod, giving builders and engineers a single rod solution across multiple critical structural applications.

Key Features

• Precut 48 in. length - ready to install straight out of the box, eliminating on-site cutting and saving labor time during structural assembly.
• Grade 55 specification - delivers a minimum yield strength of 55 ksi (Fy = 55 ksi) and a minimum tensile strength of 75 ksi (Fu = 75 ksi) per ASTM A36, providing the structural integrity required for seismic and wind-resisting systems.
• UNC Class 2A thread specification - ensures precise, standardized thread fit for reliable mating with nuts, couplers, and tiedown hardware used in strong-rod systems.
• Uncoated black steel construction - a clean, no-frills finish suited for interior structural applications where corrosion exposure is not a concern, keeping costs efficient.
• 1 in. rod diameter - provides the cross-sectional area needed to carry significant tension loads in continuous rod tiedown and uplift restraint systems.
• Fully threaded along the entire 48 in. length - allows couplers, bearing plates, and tiedown hardware to be positioned anywhere along the rod, giving installers maximum flexibility in system layout.

Why This Product

• Designed specifically as a tension transfer element for seismic and wind-resisting structural systems, this all-thread rod supports a continuous load path from roof to foundation - addressing one of the most critical performance requirements in modern structural design.
• The precut 48 in. length reduces field preparation time, making it a practical choice for contractors who need consistent, installation-ready components across repetitive framing conditions.
• Its dual suitability for continuous rod tiedown systems (shearwall overturning restraint) and uplift restraint systems for roofs means a single product type can serve multiple structural roles on the same project.
• Manufactured in the United States and meeting ASTM A36 Grade 55 standards, this rod is built to verified mechanical property requirements - giving engineers and inspectors a dependable basis for structural calculations and code compliance.

Specifications

• Brand: Simpson Strong-Tie
• MPN: ATRM8-4
• Product Class: Threaded Rod
• Rod Diameter: 1 in.
• Rod Length: 48 in.
• Thread Specification: UNC Class 2A
• Grade: Grade 55
• Material Standard: ASTM A36; Fy = 55 ksi & Fu = 75 ksi
• Material: Uncoated Steel
• Finish: Uncoated Steel
• Color: Black
• Quantity: 1
• Country of Origin: United States
• Prop 65: No

Approved Applications

• Continuous rod tiedown systems for shearwall overturning restraint
• Uplift restraint systems for roofs
• Adhesive anchor rod applications
• Structural systems designed to resist seismic forces
• Structural systems designed to resist wind forces

Frequently Asked Questions

What is the difference between this all-thread rod and a standard partially threaded rod?

This ATRM rod is fully threaded along its entire 48 in. length (all-thread rod), which means nuts, couplers, bearing plates, and tiedown hardware can be engaged at any point along the rod. A partially threaded rod only has threads at one or both ends, limiting where hardware can be positioned. Full threading is required for continuous rod tiedown systems where hardware placement must be flexible.

What does Grade 55 mean for this threaded rod?

Grade 55 refers to the mechanical strength classification of this rod per ASTM A36 standards. It indicates a minimum yield strength (Fy) of 55 ksi and a minimum tensile strength (Fu) of 75 ksi. These values define how much load the rod can carry before permanent deformation or fracture, and they are the values engineers use in structural calculations for seismic and wind-resisting system design.

Can this rod be used as an adhesive anchor rod?

Yes. In addition to its role in continuous rod tiedown and uplift restraint systems, the Simpson Strong-Tie ATRM is also suitable for use as an adhesive anchor rod, making it a versatile component for a variety of structural anchoring applications.

Is this rod suitable for outdoor or exposed environments?

This rod features an uncoated black steel finish with no applied corrosion-resistant coating. It is best suited for interior or protected structural applications where direct moisture and corrosion exposure are not concerns. For applications in corrosive or outdoor environments, a coated or stainless rod option should be evaluated.