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HDB/HD Holdowns

HDB/HD

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Simpson Strong-Tie offers a wide variety of bolted holdowns offering low-deflection performance for a range of load requirements.

The HD3B is a light-duty holdown designed for use in shearwalls and braced-wall panels, as well as other lateral applications.

The HD5B, HD7B and HD9B bolted holdowns incorporate the proven design of our HDQ8 SDS-style holdown and feature a unique seat design which greatly minimizes deflection under load. HDB holdowns are self-jigging, ensuring that the code-required minimum of seven bolt diameters from the end of the post is met. They can be installed directly on the sill plate or raised above it and are suitable for back-to-back applications where eccentricity is a concern. HDBs are designed to provide loads for intermediate-load-range shearwalls, braced-wall panels and lateral applications.

HD holdowns offer high allowable loads for both vertical and horizontal applications. The HD12 and HD19 are self-jigging, ensuring that the code-required minimum of seven bolt diameters from the end of the post is met. They can be installed back-to-back when eccentricity is an issue.

Material

  • See table

Finish

  • HD3B/HD5B/HD7B/HD9B — galvanized; HD — Simpson Strong-Tie gray paint; HDG available. For stainless-steel options, see engineering letter L-C-SSHD.

Installation

  • See General Notes for Holdowns and Tension Ties
  • Bolt holes shall be a minimum of 1/32" to a maximum of 1/16" larger than the bolt diameter (per 2015/2018 NDS, section 12.1.3.2)
  • Stud bolts should be snugly tightened with standard-cut washers between the wood and nut (BPs are required in the City and County of Los Angeles)
  • HD and HDB holdowns are self-jigging and will ensure minimum bolt end distance when installed flush with the sill plate
  • Standard-cut washer is required under the anchor nut for HD12 with 1" anchor and HD19 with 1 1/8" anchors

Related Literature

Load Tables

    These products are available with additional corrosion protection. Additional products on this page may also be available with this option, check with Simpson Strong-Tie for details.

HDB/HD Holdowns Load Table
  1. To achieve published loads, machine bolts shall be installed with the nut on the opposite side of the holdown. If this orientation is reversed, the Designer shall reduce the allowable loads shown per NDS requirements when bolt threads are in the shear plane.
  2. Lag or carriage bolts are not permitted.
  3. HD19 with 1 1/4" anchor rod requires No.1 post (or better) to achieve published loads.

Code Reports & Compliance

Drawings

PDF DWG DXF RFA IFC SAT