The Simpson Strong-Bolt 2 Wedge Anchor in 1/2 in. x 8 1/2 in., Type 316 Stainless Steel is a wedge-type expansion anchor engineered for high-performance concrete fastening in the most demanding structural environments, including seismic and high-wind conditions. Dual undercutting embossments on each clip segment enable secondary expansion should a crack form and intersect the anchor location, significantly increasing the ability of Strong-Bolt 2 to carry load if the hole expands. Built entirely from Type 316 stainless steel - body, nut, washer, and clip alike - this anchor delivers long-lasting corrosion resistance across a wide variety of service environments where moisture, chemicals, or outdoor exposure are a concern.

Key Features

• Code listed for cracked and uncracked concrete applications - gives engineers and installers the confidence to use a single anchor solution across a broad range of concrete conditions without needing separate product qualifications.
• Dual undercutting embossments on each clip segment - enable secondary expansion if a crack intersects the anchor location, maintaining load-carrying capacity even as hole conditions change.
• Qualified for static and seismic loading conditions, seismic design categories A through F - meets the strictest code requirements for earthquake-prone regions and high-wind zones, making it suitable for critical structural connections.
• Chamfered top designed to prevent mushrooming during installation - protects the threads during driving so the nut seats cleanly and installation goes smoothly without rework.
• Suitable for horizontal, vertical, and overhead applications - provides installation flexibility so one anchor covers multiple orientations on the same jobsite.
• Standard ANSI fractional sizing installs with a 1/2 in. drill bit and 3/4 in. wrench - works with common tools already on the job, reducing the need for specialized equipment and keeping installation straightforward.
• Tested per ACI355.2 and AC193 - independently verified performance gives specifiers the documentation they need for code-compliant submittals.
• Type 316 stainless steel construction throughout - resists corrosion in harsh or marine-adjacent environments where standard carbon steel anchors would deteriorate prematurely.

Why This Product

• Built for the worst-case scenario. Secondary expansion capability through dual undercutting embossments means this wedge anchor continues to perform even after a concrete crack develops at the anchor location - a critical safety margin for structural and seismic applications.
• One anchor, every seismic zone. Qualification across seismic design categories A through F means this anchor satisfies code requirements from low-risk regions to the highest seismic hazard zones, simplifying product selection for mixed-jurisdiction projects.
• Corrosion resistance you can count on long-term. With every component - body, clip, washer, and nut - manufactured from Type 316 stainless steel, this anchor holds up in corrosive environments where ordinary anchors would fail well before the structure's service life ends.
• Installs without surprises. The chamfered top, standard ANSI fractional sizing, and compatibility with common drill and wrench sizes mean crews spend less time troubleshooting and more time completing the work efficiently.

Specifications

• Size: 1/2 in. x 8-1/2 in.
• MPN: STB2-50812S6F20
• Brand: Simpson Strong-Tie
• Anchor Type: Wedge-Type Expansion Anchor
• Material: Type 316 Stainless Steel
• Finish: Type 316 Stainless Steel
• Diameter: 1/2 in.
• Length: 8-1/2 in.
• Thread Length: 6 in.
• Component Material - Anchor Body: Type 316 Stainless Steel
• Component Material - Nut: Type 316 Stainless Steel
• Component Material - Washer: Type 316 Stainless Steel
• Component Material - Clip: Type 316 Stainless Steel
• Assembly: Fully Assembled
• Install With: Installs with 1/2 in. drill bit and 3/4 in. wrench size
• Testing Standards: ACI355.2 and AC193
• Packaging: Packs of 20 and Cartons of 40
• Drill Bit Diameter: 1/2 in.

Approved Applications

• Cracked concrete structural connections
• Uncracked concrete structural connections
• Seismic design categories A through F
• High-wind condition installations
• Horizontal anchor installations
• Vertical anchor installations
• Overhead anchor installations

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 enable secondary expansion should a crack form and intersect the anchor location, significantly increasing its ability to carry load if the hole expands.

What seismic design categories is this anchor qualified for?

The Strong-Bolt 2 is qualified for static and seismic loading conditions covering seismic design categories A through F, making it an optimal choice for high-performance applications in seismic and high-wind conditions.

What tools are needed to install the STB2-50812S6F20?

This anchor installs with a 1/2 in. drill bit and requires a 3/4 in. wrench size for tightening. Its standard (ANSI) fractional sizing ensures compatibility with common drill bits and tool sizes.

What standards has this anchor been tested to?

The Strong-Bolt 2 has been tested per ACI355.2 and AC193, providing verified performance data for use in code-compliant structural applications.

Note: Product dimensions and/or thread length may differ from picture. Please see the item description above for specifications.