Simpson Strong-Bolt 2 Wedge Anchor - 3/8 in. x 3 1/2 in. - Type 304 Stainless Steel is a high-performance wedge-type expansion anchor engineered for reliable concrete fastening in demanding structural applications. Built from Type 304 stainless steel throughout, this anchor delivers long-lasting corrosion resistance across a wide variety of service environments - making it a strong choice for both indoor and outdoor concrete anchoring where exposure to moisture or corrosive conditions is a concern. Designed and tested for use in cracked and uncracked concrete, it performs under seismic and high-wind loading conditions, giving contractors and engineers confidence in applications ranging from ordinary construction to seismic design categories A through F.

Key Features

• Code listed for cracked and uncracked concrete applications - qualifies for a broader range of structural and seismic anchoring jobs without requiring separate hardware for different concrete conditions
• Dual undercutting embossments on each clip segment enable secondary expansion if a crack forms and intersects the anchor location - significantly increases load-carrying ability when the hole expands, adding a critical safety margin in seismic zones
• Chamfered top design prevents mushrooming during installation - ensures clean, consistent setting and reduces the chance of installation damage that could compromise holding strength
• Qualified for static and seismic loading conditions across seismic design categories A through F - meets code requirements for the most demanding seismic applications in the US
• Suitable for horizontal, vertical, and overhead applications - provides installation flexibility across a wide range of orientations and job site conditions
• Standard ANSI fractional sizing (3/8 in.) - fits standard fixtures and installs with common drill bit and tool sizes, reducing the need for specialty equipment on the job site
• Tested per ACI355.2 and AC193 - independently verified performance standards give engineers and inspectors the documentation they need for code compliance
• Type 304 stainless steel construction throughout - resists rust and corrosion in wet, outdoor, and chemically active service environments for long service life
• Thread length of 2 1/16 in. - provides adequate thread engagement for secure nut and washer fastening with fixtures of varying thickness

Why This Product

• Engineered for seismic and high-wind conditions - if your project falls under seismic design categories A through F or requires anchors that maintain load capacity even if concrete cracks, this anchor is specifically tested and code listed for those scenarios, reducing liability and inspection risk
• Secondary expansion technology sets it apart in cracked concrete - the dual undercutting embossments on each clip segment activate if a crack intersects the anchor, helping the fastener maintain load rather than failing, which is a critical performance advantage over standard wedge anchors
• Type 304 stainless steel throughout resists corrosion in wet and outdoor environments - ideal for applications where carbon steel anchors would degrade prematurely, such as exterior concrete walls, swimming pool decks, or coastal construction
• Installs with standard 3/8 in. drill bits and common 9/16 in. wrench - no specialty tooling required, so crews can complete anchor installations using equipment already on the truck, saving time and cost on the job

Specifications

• Brand: Simpson Strong-Tie
• Diameter: 3/8 in.
• Length: 3 1/2 in.
• Thread Length: 2 1/16 in.
• Drill Bit Diameter: 3/8 in.
• Material: Type 304 Stainless Steel
• Finish: Type 304 Stainless Steel
• Anchor Type: Wedge-type expansion anchor
• Testing Standards: ACI355.2 and AC193
• Seismic Design Categories: A through F

Available Pack Options

• STB2-373124SS: 50 Pk
• STB2-373124SS -5P: 250 Pk

Approved Applications

• Cracked concrete anchoring applications
• Uncracked concrete anchoring applications
• Static loading conditions
• Seismic loading conditions - seismic design categories A through F
• High-wind condition structural connections
• Horizontal anchor installations
• Vertical anchor installations
• Overhead anchor installations

Install With

• Installs with 3/8 in. drill bit and 9/16 in. wrench size

Frequently Asked Questions

Can the Strong-Bolt 2 wedge anchor be used in cracked concrete?

Yes. This anchor is code listed for both cracked and uncracked concrete applications. The dual undercutting embossments on each clip segment provide secondary expansion if a crack forms and intersects the anchor location, significantly increasing the anchor's ability to carry load even when the hole expands.

What seismic design categories is this anchor qualified for?

The Strong-Bolt 2 wedge anchor is qualified for static and seismic loading conditions covering seismic design categories A through F - the full range of seismic design categories used in US construction. It has been tested per ACI355.2 and AC193.

Why is Type 304 stainless steel used for this anchor?

Type 304 stainless steel provides long-lasting corrosion resistance for a wide variety of service environments. This makes the anchor well suited for outdoor, wet, or corrosive exposure conditions where carbon steel hardware would deteriorate over time. The anchor body, nut, washer, and clip are all manufactured from stainless steel materials.

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

This anchor installs with a standard 3/8 in. drill bit and requires a 9/16 in. wrench. The standard ANSI fractional sizing means it works with common drill bits and tool sizes already found on most job sites, with no specialty equipment required.

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