The Simpson Strong-Bolt 2 1/2 in. x 4-3/4 in. Wedge Anchor in Type 316 Stainless Steel is a wedge-type expansion anchor engineered for high-performance concrete fastening in the most demanding conditions. Built around a dual undercutting embossment design on each clip segment, this anchor achieves secondary expansion if a crack forms and intersects the anchor location - helping it maintain load capacity even as the hole expands. Code listed for both cracked and uncracked concrete and qualified for seismic design categories A through F, it is an optimal choice for structural connections where reliability under static, seismic, and high-wind loading is non-negotiable. Every component - body, nut, washer, and clip - is manufactured from Type 316 stainless steel, delivering consistent, long-lasting corrosion resistance across a wide variety of service environments.

Key Features

• Code listed for cracked and uncracked concrete - gives engineers and installers the confidence to specify this anchor across a broad range of concrete substrate conditions without needing a separate product for each scenario.
• Dual undercutting embossments on each clip segment enable secondary expansion - if a crack intersects the anchor location, the design significantly increases the anchor's ability to carry load as the hole expands, improving safety in real-world conditions.
• Qualified for seismic design categories A through F and high-wind conditions - meets the requirements for the most demanding structural loading scenarios, making it suitable for seismic zones and wind-critical applications alike.
• Chamfered top prevents mushrooming during installation - protects the anchor threads and head during driving, ensuring clean, reliable installation every time.
• Suitable for horizontal, vertical, and overhead applications - provides flexibility across a wide range of installation orientations without requiring different fastener types.
• Standard ANSI fractional sizing (1/2 in. diameter) - fits standard fixtures and installs with common drill bit and tool sizes, reducing setup time and the need for specialty equipment on the job site.
• Tested per ACI355.2 and AC193 - independently verified to meet recognized industry test standards, supporting code compliance and engineering documentation.
• All components made from Type 316 stainless steel - ensures uniform, long-lasting corrosion resistance throughout the entire assembly, not just the anchor body, making it well suited for exterior, coastal, and other corrosive service environments.
• Installs with a 1/2 in. drill bit and 3/4 in. wrench - uses common, readily available tools so installation crews can work efficiently without sourcing specialty hardware.

Why This Product

• Built to hold when concrete cracks - the dual undercutting embossment system is specifically engineered to trigger secondary expansion if a crack forms at the anchor location, a critical advantage in seismic and high-stress applications where ordinary wedge anchors can lose holding power.
• All-316 stainless steel construction throughout every component - unlike anchors that use stainless steel only on the body while other components corrode, this anchor uses Type 316 stainless steel for the body, nut, washer, and clip, delivering uniform protection suited to wet, coastal, and chemically challenging environments.
• Covers the full spectrum of seismic design categories - with qualification across seismic categories A through F and suitability for high-wind conditions, a single anchor model can be specified on projects ranging from low-risk to high-seismic-hazard zones, simplifying procurement and inventory.
• Designed for straightforward installation with no specialty tooling - the chamfered top, standard ANSI fractional sizing, and compatibility with a common 1/2 in. drill bit mean crews spend less time on setup and more time on the work, reducing labor overhead on concrete fastening tasks.

Specifications

• Model Number: STB2-50434S6F25
• Coating / Material: Type 316 Stainless Steel
• Size: 1/2 in. x 4-3/4 in.
• Drill Bit Diameter: 1/2 in.
• Thread Length: 3-1/16 in.
• Anchor Body Material: Type 316 Stainless Steel
• Nut Material: Type 316 Stainless Steel
• Washer Material: Type 316 Stainless Steel
• Clip Material: Type 316 Stainless Steel
• Packaging: Packs of 25 and Cartons of 100

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 allow secondary expansion should a crack form and intersect the anchor location, helping the anchor maintain load capacity even as the hole expands.

Why is Type 316 stainless steel used for this anchor?

Type 316 stainless steel offers long-lasting corrosion resistance across a wide variety of service environments. Every component of this anchor - including the body, nut, washer, and clip - is made from Type 316 stainless steel, ensuring consistent protection throughout the entire assembly.

What drill bit diameter is required to install this anchor?

Installation requires a 1/2 in. diameter drill bit, which matches the anchor's 1/2 in. diameter and ensures a proper fit within the concrete substrate.

Is this anchor appropriate for seismic or high-wind applications?

Yes. The Strong-Bolt 2 wedge anchor is described as an optimal choice for high-performance applications, including those subject to seismic and high-wind conditions, making it well suited for structurally critical installations.

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