The Simpson Strong-Bolt 2 Wedge Anchor (3/8 in. x 3 1/2 in., Zinc Plated) is a wedge-type expansion anchor engineered by Simpson for high-performance concrete fastening in the most demanding structural conditions, including seismic and high-wind environments. Dual undercutting embossments on each clip segment enable secondary expansion should a crack form and intersect the anchor location, significantly increasing the ability of the Strong-Bolt 2 to carry load if the hole expands - making it a dependable choice for both cracked and uncracked concrete fastening. Tested per ACI355.2 and AC193, this carbon steel anchor delivers verified performance across a wide range of installation orientations and structural applications.

Key Features

• Chamfered top - prevents mushrooming during installation, protecting thread integrity and reducing the risk of installation errors.
• Dual undercutting embossments on each clip segment - enable secondary expansion if a crack intersects the anchor location, allowing the anchor to continue carrying load even as concrete conditions change.
• Qualified for static and seismic loading conditions (seismic design categories A through F) - gives engineers and contractors confidence when specifying anchors for high-wind or seismic-zone structural connections.
• Suitable for horizontal, vertical, and overhead applications - provides installation flexibility across a wide variety of jobsite conditions and structural configurations.
• Tested per ACI355.2 and AC193 - ensures the anchor meets recognized industry standards, supporting code-compliant installations and third-party verification.
• Zinc-plated carbon steel construction - offers corrosion resistance suitable for standard interior and protected concrete anchoring applications.

Why This Product

• Built for seismic and high-wind reliability - the Strong-Bolt 2 is qualified for seismic design categories A through F and tested under static and seismic loading conditions, making it one of the few wedge anchors suited for the most structurally demanding environments.
• Secondary expansion technology protects load capacity in cracked concrete - the dual undercutting embossments on each clip segment are specifically designed to expand further if a crack develops, a critical safety advantage that standard wedge anchors typically do not provide.
• Versatile installation across multiple orientations - approved for horizontal, vertical, and overhead use, this expansion anchor adapts to a broad range of concrete fastening scenarios without requiring a different product for each application.
• Third-party tested and code-supported - with testing per ACI355.2 and AC193, the Strong-Bolt 2 supports documentation requirements for permitted work, giving contractors and engineers a straightforward path to code compliance on structural projects.

Specifications

• Size: 3/8 in. x 3-1/2 in.
• MPN: STB2-37312F50
• Brand: Simpson Strong-Tie
• Diameter: 3/8 in.
• Length: 3-1/2 in.
• Thread Length: 2-1/16 in.
• Material: Carbon Steel
• Coating: Zinc Plated
• Finish: Zinc Plated
• Installation Drill Bit: 3/8 in.
• Wrench Size: 9/16 in.
• Packaging: Packs of 50 and Cartons of 250

Approved Applications

• Cracked and uncracked concrete fastening
• Masonry applications
• Horizontal installations
• Vertical installations
• Overhead installations
• Seismic design categories A through F
• High-wind structural connections

Frequently Asked Questions

What size drill bit and wrench are required to install the Strong-Bolt 2?

The Strong-Bolt 2 STB2-37312F50 installs with a 3/8 in. drill bit and requires a 9/16 in. wrench size for proper installation.

Is the Strong-Bolt 2 rated for seismic conditions?

Yes. The Strong-Bolt 2 is qualified for static and seismic loading conditions, covering seismic design categories A through F, making it suitable for use in the most demanding seismic and high-wind environments.

Can this wedge anchor be used in cracked concrete?

Yes. The Strong-Bolt 2 features dual undercutting embossments on each clip segment that enable secondary expansion should a crack form and intersect the anchor location. This significantly increases the ability of the Strong-Bolt 2 to carry load if the hole expands, making it suitable for both cracked and uncracked concrete applications.

What other material options are available for the Strong-Bolt 2?

In addition to the zinc-plated carbon steel version, the Strong-Bolt 2 is available in mechanically galvanized carbon steel, Type 304 stainless steel, and Type 316 stainless steel to suit various environmental and corrosion-resistance requirements.

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