The Simpson Strong-Bolt 2 Wedge Anchor in 1/2 in. x 5 1/2 in. by Simpson is a high-performance wedge-type expansion anchor engineered for demanding structural fastening applications in concrete. Built from Type 304 stainless steel throughout, this anchor delivers long-lasting corrosion resistance across a wide range of service environments - making it a reliable choice for projects exposed to moisture, chemicals, or other corrosive conditions. Designed to perform in both cracked and uncracked concrete, the Strong-Bolt 2 is qualified for static and seismic loading, making it an optimal solution for structures in seismic design categories A through F and high-wind zones.

Key Features

• Code listed for cracked and uncracked concrete applications - provides verified performance and code compliance across a broader range of real-world concrete conditions, reducing engineering risk
• Dual undercutting embossments on each clip segment enable secondary expansion if a crack forms and intersects the anchor - significantly increases the anchor's ability to carry load even when the hole expands, adding a critical safety margin
• Chamfered top designed to prevent mushrooming during installation - protects the threads and ensures a clean, reliable installation without damage to the bolt head
• Qualified for static and seismic loading conditions, seismic design categories A through F - meets the requirements for the most demanding seismic and high-wind structural applications
• Suitable for horizontal, vertical, and overhead applications - provides versatile placement options so the same anchor can be used throughout a project regardless of orientation
• Standard ANSI fractional sizes - fits standard fixtures and installs with common drill bit and tool sizes, eliminating the need for specialty tooling
• Tested per ACI 355.2 and AC193 - independently verified performance gives engineers and inspectors the documentation they need for code-compliant installations
• Type 304 stainless steel construction - resists corrosion in wet, humid, and chemically active service environments for long-term structural integrity
• Thread length of 3 13/16 in. - provides ample thread engagement for secure fastening in a wide range of fixture thicknesses

Why This Product

• Engineered specifically for seismic and high-wind conditions - the Strong-Bolt 2's dual undercutting clip design maintains load-carrying capacity even if cracking occurs at the anchor location, making it the right choice for structures in seismic design categories A through F where anchor performance under dynamic loading is critical
• Type 304 stainless steel construction means this anchor resists corrosion in challenging environments where standard carbon steel or zinc-plated anchors would degrade over time - ideal for applications where long-term corrosion resistance is a project requirement
• ANSI fractional sizing (1/2 in. diameter) installs with a standard 1/2 in. drill bit and a 3/4 in. wrench - no specialty equipment needed, saving time and cost on the job site
• Code listed for both cracked and uncracked concrete and tested per ACI 355.2 and AC193 - provides the engineering documentation and listing status needed to satisfy inspection and permitting requirements on commercial, residential, and industrial projects

Specifications

• Brand: Simpson Strong-Tie
• Diameter: 1/2 in.
• Length: 5 1/2 in.
• Thread Length: 3 13/16 in.
• Drill Bit Diameter: 1/2 in.
• Material: Type 304 Stainless Steel
• Finish: Type 304 Stainless Steel
• Testing Standards: ACI 355.2 and AC193

Available Pack Options

• STB2-505124SS: 25 Pk
• STB2-505124SS -4P: 100 Pk

Install With

• Installs with 1/2 in. drill bit and 3/4 in. wrench size

Frequently Asked Questions

Is the Strong-Bolt 2 suitable for use in cracked concrete?

Yes. The Strong-Bolt 2 is code listed for both cracked and uncracked concrete applications. Its dual undercutting embossments on each clip segment allow secondary expansion if a crack forms and intersects the anchor location, which significantly increases the anchor's ability to carry load even when the surrounding concrete has cracked.

What seismic design categories is the Strong-Bolt 2 qualified for?

The Strong-Bolt 2 is qualified for static and seismic loading conditions covering seismic design categories A through F - the full range of seismic risk classifications. It is also rated for high-wind conditions, making it a reliable choice for structures in geographically demanding locations.

What drill bit and wrench size are needed to install this anchor?

This 1/2 in. anchor installs with a standard 1/2 in. drill bit and requires a 3/4 in. wrench for tightening. The ANSI fractional sizing means no specialty tooling is required - common drill and fastening equipment found on most job sites is sufficient.

Why is Type 304 stainless steel used for this anchor?

Type 304 stainless steel provides long-lasting corrosion resistance across a wide variety of service environments. This makes the Strong-Bolt 2 stainless-steel wedge anchor well suited for applications where exposure to moisture, humidity, or corrosive conditions would cause standard carbon steel anchors to degrade prematurely.