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HDU Holdown

HDU

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The HDU is designed for use in shearwalls and braced-wall panels, as well as other lateral applications in wood construction. The HDU uses Strong-Drive® SDS Heavy-Duty Connector screws which install easily, reduce fastener slip and provide a greater net section than bolts.

Key Features

  • Strong-Drive SDS Heavy-Duty Connector screws are supplied with the holdown to ensure proper fasteners are used
  • Predeflected seat eliminating deflection under load
  • No stud bolts to countersink at openings

Material

  • See table

Finish

  • Galvanized

Installation

  • See General Notes for Holdowns and Tension Ties.
  • The HDU requires no additional washer.
  • Strong-Drive SDS Heavy-Duty Connector screws install best with a low-speed, high-torque drill equipped with a 3/8" hex-head driver.
  • Fasteners and crescent washer are included with the holdowns. For replacements, order part no. SDS25212-HDU_. (Fill in the size needed, e.g., HDU2.)

Related Literature

Wood Construction Connectors 2021-2023
C-C-2021
A catalog including new product information as well as any applicable specification and installation instructions for wood-to-wood and wood-to-concrete structural connectors.
Catalog
Conectores para la construcción con madera 2019–2020
C-C-2019SP
El catálogo incluye información sobre nuevos productos, así como especificaciones e instrucciones de instalación aplicables para conectores estructurales de madera a madera y de madera a concreto.
Catalog
High Wind Guide
F-C-HWG20
A comprehensive guide to help Designers select the most appropriate connections for challenging, high-wind regions.
Product Guide
ICF Connectors
F-C-ICFVL19
A flier featuring installation instructions for the ICFVL ledger connector system and provides information on the various products we have to serve the ICF market.
Flier
Soft-Story Retrofit Solutions for Northern California
F-L-20NCSSR20
A flier offering a variety of Simpson Strong-Tie® state-of-the-art structural retrofit solutions specifically designed to meet recent Northern California soft-story retrofit mandates.
Flier
Connector Solutions to Meet the Wall Bracing Requirements of the International Residential Code®
T-C-WALLBRACE21
A technical bulletin providing technical information about wall bracing methods and code sections that require connectors (e.g., holdowns or straps) and anchors.
Technical Bulletin
Connectors Installed on SCL Columns
T-C-SCLCLM21
A technical bulletin discussing the structural properties of the two different surface sides of SCL columns.
Technical Bulletin
Connectors Installed on SCL Columns
T-C-SCLCLMCAN20
A Canadian Limit States technical bulletin addressing typical installations of Simpson Strong-Tie® connectors on SCL columns as well as reduction factors for narrow-face SCL installations.
Technical Bulletin
Simpson Strong-Tie® Holdowns on Cross-Laminated Timber Panels
L-C-HDCLT21
Simpson Strong-Tie evaluated the HDQ/HHDQ, HDU and HTT holdowns in cross-laminated timber (CLT) panel applications installed with SD and SDS screws.
Engineering Letter

Product Information Table

Fastener Production Information and Stuff & Things
Model No. Ga. W (in.) H (in.) B (in.) CL (in.) SO (in.) Coating/Material Product Includes Packaging Qty.
HDU11-SDS2.5 10 3 22 1/4 3 1/2 1 3/8 1 1/2 Zinc Galvanized, G90 (30) 1/4 in. x 2-1/2 in. Strong-Drive SDS Heavy-Duty Connector screws and (1) crescent washer 1
HDU11-SDS2.5HDG 10 3 22 1/4 3 1/2 1 3/8 1 1/2 Hot-Dip Galvanized (30) 1/4 in. x 2-1/2 in. Strong-Drive SDS Heavy-Duty Connector screws and (1) crescent washer 1
HDU14-SDS2.5 7 3 25 11/16 3 1/2 1 9/16 1 9/16 Zinc Galvanized, G90 (36) 1/4 in. x 2-1/2 in. Strong-Drive SDS Heavy-Duty Connector screws, (1) crescent washer and (1) heavy-hex anchor nut 1
HDU14-SDS2.5HDG 7 3 25 11/16 3 1/2 1 9/16 1 9/16 Hot-Dip Galvanized (36) 1/4 in. x 2-1/2 in. Strong-Drive SDS Heavy-Duty Connector screws, (1) crescent washer and (1) heavy-hex anchor nut 1
HDU2-SDS2.5 14 3 8 11/16 3 1/4 1 5/16 1 3/8 Zinc Galvanized, G90 (6) 1/4 in. x 2-1/2 in. Strong-Drive SDS Heavy-Duty Connector screws and (1) crescent washer 1
HDU2-SDS2.5HDG 14 3 8 11/16 3 1/4 1 5/16 1 3/8 Hot-Dip Galvanized (6) 1/4 in. x 2-1/2 in. Strong-Drive SDS Heavy-Duty Connector screws and (1) crescent washer 1
HDU4-SDS2.5 14 3 10 15/16 3 1/4 1 5/16 1 3/8 Zinc Galvanized, G90 (10) 1/4 in. x 2-1/2 in. Strong-Drive SDS Heavy-Duty Connector screws and (1) crescent washer 1
HDU4-SDS2.5HDG 14 3 10 15/16 3 1/4 1 5/16 1 3/8 Hot-Dip Galvanized (10) 1/4 in. x 2-1/2 in. Strong-Drive SDS Heavy-Duty Connector screws and (1) crescent washer 1
HDU5-SDS2.5 14 3 13 3/16 3 1/4 1 5/16 1 3/8 Zinc Galvanized, G90 (14) 1/4 in. x 2-1/2 in. Strong-Drive SDS Heavy-Duty Connector screws and (1) crescent washer 1
HDU5-SDS2.5HDG 14 3 13 3/16 3 1/4 1 5/16 1 3/8 Hot-Dip Galvanized (14) 1/4 in. x 2-1/2 in. Strong-Drive SDS Heavy-Duty Connector screws and (1) crescent washer 1
HDU8-SDS2.5 10 3 16 5/8 3 1/2 1 3/8 1 1/2 Zinc Galvanized, G90 (20) 1/4 in. x 2-1/2 in. Strong-Drive SDS Heavy-Duty Connector screws and (1) crescent washer 1
HDU8-SDS2.5HDG 10 3 16 5/8 3 1/2 1 3/8 1 1/2 Hot-Dip Galvanized (20) 1/4 in. x 2-1/2 in. Strong-Drive SDS Heavy-Duty Connector screws and (1) crescent washer 1

Load Tables

  These products are available with additional corrosion protection.

HDU Load Table
  1. HDU14 requires heavy-hex anchor nut to achieve tabulated loads (supplied with holdown).
  2. HDU14 loads on 4x6 post are applicable to installation on either the narrow or the wide face of the post.
  3. Fasteners: Nail dimensions are listed diameter by length. SD and SDS screws are Simpson Strong-Tie® Strong-Drive SD Connector and SDS Heavy-Duty Connector screws. For additional information, see Fastener Types and Sizes Specified for Simpson Strong-Tie Connectors.

Code Reports & Compliance

Drawings

PDF DWG DXF RFA IFC SAT

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