The Simpson Strong-Bolt 2 1/2 in. x 4-1/4 in. Wedge Anchor is a high-performance wedge-type expansion anchor from Simpson, engineered for demanding structural fastening in cracked and uncracked concrete as well as masonry. Dual undercutting embossments on each clip segment enable secondary expansion should a crack form and intersect the anchor location, significantly increasing the anchor's ability to carry load even as conditions change. Qualified for static and seismic loading across seismic design categories A through F, this zinc-plated carbon steel anchor delivers reliable holding power for horizontal, vertical, and overhead installations in high-seismic and high-wind environments.

Key Features

• Dual undercutting embossments on each clip segment - enable secondary expansion if a crack forms and intersects the anchor, helping maintain load capacity when concrete conditions shift.
• Code listed for cracked and uncracked concrete, and masonry applications - gives contractors and engineers confidence the anchor meets recognized standards across a wide range of base materials.
• Qualified for static and seismic loading conditions (seismic design categories A through F) - makes this anchor a dependable choice for structural connections in the most demanding seismic and high-wind regions.
• Chamfered top designed to prevent mushrooming during installation - promotes a clean, flush fit and reduces the risk of installation damage that could compromise holding strength.
• Suitable for horizontal, vertical, and overhead applications - provides flexibility across a broad range of jobsite orientations without requiring a different anchor for each condition.
• Tested per ACI355.2 and AC193 - independently verified performance gives engineers and inspectors the documentation needed for code-compliant projects.
• Zinc-plated carbon steel construction - provides a corrosion-resistant finish suited for standard interior and protected structural applications.

Why This Product

• Built for cracked concrete without compromise - the secondary expansion feature means the anchor continues to perform even after a crack intersects the installation point, reducing the need for costly rework or replacement in aging or stressed concrete.
• Full seismic range coverage - with qualification across seismic design categories A through F, this wedge anchor handles everything from low-risk zones to the highest-seismic regions, eliminating the need to source a different product for each project location.
• Straightforward installation with standard tools - installs with a 1/2 in. drill bit and 3/4 in. wrench, and the chamfered top guards against mushrooming, so crews can work efficiently without specialized equipment or extra prep steps.
• Versatile approval for multiple application types - code listing for cracked concrete, uncracked concrete, and masonry, combined with suitability for horizontal, vertical, and overhead use, makes this a single anchor solution across a wide range of structural fastening tasks.

Specifications

• Size: 1/2 in. x 4-1/4 in.
• MPN: STB2-50414F25
• Brand: Simpson Strong-Tie
• Diameter: 1/2 in.
• Length: 4-1/4 in.
• Thread Length: 2-9/16 in.
• Material: Carbon Steel
• Coating / Finish: Zinc Plated
• Installation: Installs with 1/2 in. drill bit and 3/4 in. wrench size
• Packaging: Packs of 25 and Cartons of 200
• Drill Bit Diameter: 1/2 in.

Approved Applications

• Cracked concrete
• Uncracked concrete
• Masonry
• Horizontal installations
• Vertical installations
• Overhead installations
• Seismic and high-wind structural connections (seismic design categories A through F)

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, as well as masonry applications. Its dual undercutting embossments on each clip segment enable secondary expansion should a crack form and intersect the anchor location, which significantly increases the ability of the anchor to carry load if the hole expands.

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, making it suitable for a wide range of structural applications in high-seismic and high-wind environments.

What tools are needed to install this wedge anchor?

Installation requires a 1/2 in. drill bit to bore the hole and a 3/4 in. wrench to tighten the anchor. The chamfered top is designed to prevent mushrooming during installation, helping ensure a clean, secure fit.

What testing standards has the Strong-Bolt 2 been evaluated under?

The Strong-Bolt 2 has been tested per ACI355.2 and AC193, which are the recognized industry standards for evaluating the performance of mechanical anchors in concrete.

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