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HTT4
HTT4
HTT4 Illustration
HTT4 Illustration
HTT5
HTT5
HTT5 Illustration
HTT5 Illustration
HTT5 Kit
HTT5 Kit

Simpson Strong‑Tie offers a wide variety of holdown devices designed and tested to address many applications and load demands. The HTT Tension Tie & Holdown is designed for heavy‑duty holdown applications on single or double studs and offer a solution for resisting tension loads. 

The heavy‑duty HTT is ideal for retrofit or new construction projects. They provide high-strength, post-pour, concrete-to-steel connections. The HTT is also suitable for residential and commercial projects, sub diaphragm floor, seismic upgrades, mid floor vertical connection applications. 

The HTT is a single-piece formed tension tie — no rivets, no welding points and a 4-ply formed seat. No washers are required. They feature an optimized nailing pattern which results in better performance with less deflection.

Please check Corrossion Information if it is suitable for your application.

Material

Carbon Steel 3.1mm thick

Finish

Z275 Galvanised

Features & Benefits
  • A single piece folded and no weak point of welding, provide ultimate strength tension tile
  • Unique nailing patten that provides better results with less deflection
  • Stronger and safer than typical through-bolt installations for deck post connections
  • Uses Strong-Drive® SDS Heavy-Duty Connector screws which install easily, reduce fastener slip and provide a greater net section area of the post compared to bolts
  • Suitable for heavy duty holdown applications on single or double studs
  • Helps prevent a common type of deck failure
  • 15mm diameter anchor hole can accommodate Simpson Strong-Tie M12 Titen HD Screw Anchor or any M14 threaded rods
  • HTT5 and HTT5KT are suitable for steel frame holdown connections
Installation
  • Use all specified fasteners
  • The HTT requires no additional washer
  • Strong‑Drive SDS Heavy‑Duty Connector screws install best with a low speed high torque drill with a 3/8” hex head driver
Model No. Table

Model No.

Dimensions (mm)

Fasteners

Minimum Timber Member Size (Depth x Breadth, mm)

Country

Design Tension Capacity (kN)

Strap
Thickness

W

H

B

CL

Anchor Bolt Dia (mm)

Post (Nails: No. - Length x Dia., Screws: No. - Dia. x Length, mm)

HTT4

3.1

63

315

60

33

14

18 – 38 x 3.75

140 x 38

AU

k1 = 1.14

15.30

NZ

k1 = 1.0

14.40

90 x 75

AU

k1 = 1.14

18.38

NZ

k1 = 1.0

17.05

18 – SD#10 x 38

140 x 38 or 90 x 75

AU

k1 = 1.14

23.04

NZ

k1 = 1.0

18.97

HTT5

3.1

63

405

60

33

14

26 - 38 x 3.75

90 x 75

AU

k1 = 1.14

20.44

NZ

k1 = 1.0

17.05

26 - SD#10 x 38

140 x 38

AU

k1 = 1.14

28.91

NZ

k1 = 1.0

21.31

  1. Design Capacity is the lesser of (1) the Characteristic Capacity multiplied by the Australian Capacity Factor, or the NZ Strength Reduction Factor (φ), and applicable the k modification factors following AS 1720.1 and NZS 3603 and (2) the Serviceability Capacity which is the load at 6.4mm joint slip, which includes fastener slip, anchor elongation and holdown deformation. Design Capacity is the minimum of test data and structural joint calculation.
  2. For Australia, the Capacity Factor (φ) is 0.85 for nails and screws for structural joints in a Category 1 application. Reduce tabulated values where other Category applications govern. For NZ, the Strength Reduction Factor (φ) is 0.80 for nails in lateral load and 0.70 for other fasteners.
  3. Duration of Load Factor (k1) is as shown. Reduce Duration of Load Factor where applicable. Capacities may not be increased.
  4. Timber species for joint design is seasoned Radiata Pine, which is Australia Joint Group JD4 per AS 1720.1 Table H2.4 and New Zealand Joint Group J5 per NZS 3603 Table 4.1.
  5. The Designer must specify anchor bolt type, length and embedment. Fasteners for the HTT4 are sold separately.
  6. Anchor bolt nut should be finger tight plus 1/3 to 1/2 turn with a hand wrench. Care should be taken not to over-tighten the nut.
  7. Post or beam design by Designer. Posts may consist of multiple members provided they are connected independently of the holdown fasteners.
  8. Structural composite timber columns have sides that either show the wide face or the edges of the timber strands/ veneers, known as the narrow face.
  9. Simpson Strong-Tie stainless-steel connectors require stainless-steel fasteners. Values in the table reflect installation into the wide face.
  10. Holdowns and tension ties are for use in vertical or horizontal applications.
  11. Holdowns and tension ties may be installed raised up to 460mm above the top of the concrete with no load reduction, provided that additional elongation of the anchor rod is taked into account.
Brochures & Catalogues
Installation Guides

Installation Guides

PDF icon HTT Installation Guides
Technical Data & Docs

Technical Data Sheets

PDF icon Technical Data Sheet - HTT

Report Links

Warranty

Warranty

CAD Library
Alternative Products

Alternative Products

DTT Tension Tie & Holdown

Simpson Strong‑Tie offers a wide variety of holdown devices designed and tested to address many applications and load demands. The DTT Tension Tie & Holdown is designed for lighter‑duty holdown applications on single or double studs.

HDU8_SDS2.5

Simpson Strong‑Tie offers a wide variety of holdown devices engineered and tested to perform and manufactured to the highest quality standards.

Inspiration
Request a Demo

Request a Demo/Sample

Experience the innovation design of Simpson Strong-Tie's products and how we can help you build safer, stronger structures. Please fill out your details and submit the form below. We’ll be in touch to schedule a time to talk and give you a personal demo of Simpson Strong-Tie products.

Request a Demo/Sample

Experience the innovation design of Simpson Strong-Tie's products and how we can help you build safer, stronger structures. Please fill out your details and submit the form below. We’ll be in touch to schedule a time to talk and give you a personal demo of Simpson Strong-Tie products.

Structural Connections

 

Unmatched Quality from the Truss to the Foundation

With nearly 60 years of field and R&D experience, Simpson Strong-Tie® timber connectors are manufactured to the industry's highest standards. From framing angles to straps to heavy-duty joist hangers, we offer the most diverse product line so that you have the right product for the job.

Simpson Strong-Tie® connectors offer unmatched quality with laboratory and field testing, and are backed by our uncompromising commitment to customer service. As the company that built the connector industry, you can count on Simpson Strong-Tie® to work closely with builders, engineers and building officials to deliver innovative, building code-compliant solutions to help build safer, stronger structures economically. Download the Structural Connectors Overview Flyer.

Timber Connectors

From testing to service to availability, everything we do is engineered to ensure your project's success. With every product, you know you are getting the quality, value, service and on-time delivery that we have built our reputation on for the past 60 years.

From straps and ties to joist hangers and much more, Simpson Strong-Tie® structural connectors increase the strength and safety of timber-frame structures. Each connector is unique to Simpson Strong-Tie and is designed for specific applications without the need to adapt metal plating to suit a connection. Download the Timber Construction Connectors Catalogue.