The Simpson Strong-Bolt 2 Wedge Anchor is a 5/8 in. x 5 in. wedge-type expansion anchor made entirely from Type 304 stainless steel, engineered for high-performance concrete anchoring in the most demanding structural environments. Purpose-built to perform reliably under seismic and high-wind conditions, this anchor is equally at home in cracked and uncracked concrete, making it a trusted solution for contractors and engineers working on projects where code compliance and long-term durability are non-negotiable. Its fully assembled design pairs with common drill bit and wrench sizes, keeping installation straightforward across horizontal, vertical, and overhead applications.

Key Features

• Dual undercutting embossments on each clip segment - enable secondary expansion if a crack forms and intersects the anchor location, significantly increasing load-carrying capacity even as the hole expands, giving you dependable holding strength in compromised concrete.
• Code listed for cracked and uncracked concrete applications - meets recognized code requirements in both conditions, reducing approval hurdles and giving inspectors and engineers the documentation they need.
• Chamfered top designed to prevent mushrooming during installation - protects the anchor head during driving so the nut seats cleanly, minimizing installation errors and rework.
• Qualified for static and seismic loading conditions (seismic design categories A through F) - covers the full range of seismic design categories, making this anchor appropriate for projects in virtually any geographic region with seismic or high-wind requirements.
• Suitable for horizontal, vertical, and overhead applications - versatile orientation capability means one anchor handles the varied installation angles common on structural, mechanical, and utility projects.
• Standard (ANSI) fractional sizes - fits standard fixtures and works with a 5/8 in. drill bit and a 15/16 in. wrench, so no specialty tooling is required and installation stays efficient.
• Tested per ACI 355.2 and AC193 - independently verified performance data supports engineering calculations and simplifies specification and approval on regulated projects.
• Type 304 stainless steel construction throughout - delivers long-lasting corrosion resistance across a wide variety of service environments, including moisture-exposed and chemically active settings where carbon steel anchors would degrade.

Why This Product

• Built for the toughest code environments - qualified across all seismic design categories (A through F) and tested per ACI 355.2 and AC193, this wedge anchor is one of the few expansion anchors engineered to satisfy the strictest seismic and high-wind project specifications without substitution or special engineering.
• Uniquely reliable in cracked concrete - the dual undercutting embossments provide secondary expansion if cracking intersects the anchor, a design feature that actively maintains load capacity rather than simply tolerating degraded conditions - critical for structures where concrete integrity may change over time.
• Corrosion resistance without compromise - with the anchor body, nut, washer, and clip all in stainless steel, this anchor is built to outlast standard zinc-plated alternatives in wet, coastal, chemical, or otherwise corrosive service environments.
• Installs with standard tools, no learning curve - ANSI fractional sizing, a 5/8 in. drill bit, and a 15/16 in. wrench are all that is required, so crews can work efficiently without sourcing specialty equipment or adjusting established workflows.

Specifications

• Model Number: STB2-62500S4F20
• Size: 5/8 in. x 5 in.
• Diameter: 5/8 in.
• Length: 5 in.
• Thread Length: 2-15/16 in.
• Material: Type 304 Stainless Steel
• Finish: Type 304 Stainless Steel
• Anchor Body: Type 304 Stainless Steel
• Nut: Type 304 Stainless Steel
• Washer: Type 304 Stainless Steel
• Clip: Type 304 or Type 316 Stainless Steel
• Installation: Installs with 5/8 in. drill bit and 15/16 in. wrench size
• Packaging: Packs of 20 and Cartons of 80
• Drill Bit Diameter: 5/8 in.

Approved Applications

• Cracked concrete anchoring
• Uncracked concrete anchoring
• Seismic design categories A through F
• Static loading conditions
• High-wind condition installations
• Horizontal, vertical, and overhead 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 anchoring in seismic and high-wind conditions.

What tools are required to install this wedge anchor?

This anchor installs with a 5/8 in. drill bit and a 15/16 in. wrench size. The chamfered top is specifically designed to prevent mushrooming during installation for a cleaner, more reliable result.

What standards has the Strong-Bolt 2 been tested to?

The Strong-Bolt 2 has been tested per ACI355.2 and AC193, ensuring it meets rigorous performance and safety benchmarks for concrete anchor applications.

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