Simpson HD3B HDB 8-5/8 in. 12-Gauge Galvanized Bolted Holdown is engineered by Simpson to deliver reliable, low-deflection performance for intermediate-load-range shearwalls, braced-wall panels, and lateral applications in wood construction. Installed with bolts directly into studs or columns, this holdown is equally suited for back-to-back configurations where eccentricity is a concern, making it a dependable choice for a broad range of wood-framed structural connections.

Key Features

• Installed after concrete placement and framing is in place - allows the holdown to be incorporated without disrupting the construction sequence, supporting flexible project scheduling.
• Can be installed directly on the sill plate or raised above it - gives contractors the flexibility to accommodate varying field conditions and project-specific requirements.
• Self-jigging design - automatically achieves the code-required minimum of seven bolt diameters from the end of the post when installed flush with the sill plate, reducing the risk of improper spacing and speeding up installation.
• Suited for back-to-back applications where eccentricity is a concern - supports symmetrical holdown configurations that help manage eccentric loading, broadening its usefulness across complex shearwall assemblies.
• Constructed from 12-gauge steel - provides the structural integrity needed for intermediate-load lateral applications in wood construction.
• G90 zinc galvanized finish - delivers meaningful corrosion resistance, supporting long-term performance in a variety of installation environments.
• Install with 5/8 in. anchor bolt and 5/8 in. stud machine bolts - uses commonly available fasteners, keeping installation straightforward and compatible with standard jobsite inventory.

Why This Product

• Low-deflection performance across a range of loads - the HD3B is specifically designed to deliver low-deflection results for intermediate-load-range shearwalls and braced-wall panels, supporting structural integrity where lateral resistance matters most.
• Self-jigging for code compliance without guesswork - the built-in self-jigging feature automatically positions the holdown to meet the code-required minimum bolt spacing from the post end, reducing installation errors and saving layout time on the job.
• Versatile placement options - whether installed flush on the sill plate or raised above it, this bolted holdown adapts to different framing conditions, making it a practical solution for a wide variety of wood construction applications.
• G90 galvanized protection on a domestic-made connector - the G90 zinc galvanized coating guards against corrosion, and the connector is made in the United States, reflecting Simpson's commitment to consistent manufacturing quality.

Specifications

• MPN: HD3B
• Brand: Simpson Strong-Tie
• Gauge: 12
• Width: 2-1/2 in.
• Height: 8-5/8 in.
• Coating/Finish: Zinc Galvanized, G90
• Install With: 5/8 in. anchor bolt and 5/8 in. stud machine bolts
• Hole Bottom: 4-3/4 in.
• SB: 2-1/2 in.
• Seat Depth: 2-1/4 in.
• Centerline: 1-5/16 in.
• Screw Offset: 3/8 in.
• Country of Origin: United States

Approved Applications

• Intermediate-load-range shearwalls in wood construction
• Braced-wall panels requiring lateral load resistance
• General lateral applications in wood-framed structures
• Back-to-back holdown installations where eccentricity is a concern

Frequently Asked Questions

When during construction is the HD3B holdown installed?

The HD3B is installed after the placement of concrete and framing is in place. It can be installed directly on the sill plate or raised above it, providing flexibility depending on project requirements.

What fasteners are required to install the HD3B?

The HD3B is installed with a 5/8 in. anchor bolt and 5/8 in. stud machine bolts. Proper bolt hole sizing and snug tightening with standard cut washers are essential for correct installation.

What does the self-jigging feature of the HD3B mean for installation?

The self-jigging design ensures that the code-required minimum of seven bolt diameters from the end of the post is automatically achieved when the holdown is installed flush with the sill plate, reducing the risk of improper spacing and simplifying the installation process.

Is the HD3B suitable for back-to-back installations?

Yes. The HD3B is specifically designed to be suitable for back-to-back applications where eccentricity is a concern, making it a practical choice for paired holdown configurations in shearwall and lateral load applications.