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HDU Heavy Duty Holdown

Select your Model:

SKU: HDU8-SDS2.5

AUD$324.00per Carton

Description:

Please note: The HDU Holdown is being discontinued and replaced with the new HDUE Holdown. Please visit the HDUE product pages.

 

Simpson Strong‑Tie offers a wide variety of holdown devices engineered and tested to perform and manufactured to the highest quality standards. The HDU Holdown is pre‑deflected during the manufacturing process, virtually eliminating deflection under load due to material stretch. This super heavy duty HDU is suitable for residential and commercial projects, sub diaphragm floor, seismic upgrades, mid floor vertical connection applications. 

The HDU installs with Simpson Strong‑Tie® Strong‑Drive® SDS Heavy‑Duty Connector screws which install easily, reduce fastener slip and provide a greater net section when compared to bolts. The HDU is also ideal for retrofit or new construction projects. They provide high-strength, post-pour, concrete-to-steel connections.

Please check the Corrosion Information to see if it is suitable for your application.

Model Variants:

SKUDescriptionUnitCarton QTYPrice AUD
16-5/8IN PREDEFLECTED HOLDOWN W/SCREWSCarton6$324.00

Model No Table:

Model No.

Dimensions (mm)

Fasteners

Wall Framing Stud(s) (mm)

Country

Design Tension Capacity (kN)

Strap
Thickness

W

H

B

CL

Anchor Hole Dia. (mm)

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

HDU8-SDS2.5

3.5

75

420

90

35

23

20 – SDS6.4 x 64

(90 or 2/45)7 x 90

AU

k1 = 1.14

36.2

NZ

k1 = 1.0

29.8
  1. Design Capacity is the lesser of (1) the Characteristic Capacity multiplied by the Capacity Factor, and applicable k modification factors following AS 1720.1 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. The Capacity Factor (ϕ) for AU is 0.85 for nails and screws for structural joints in a Category 1 application, and for NZ is 0.8. Reduce tabulated values where other Category applications govern.
  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.
  5. The Designer must specify anchor bolt type, length and embedment.
  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. Minimum 90mm or 2/ 45mm thick post or studs required. Number of total studs or post size to meet axial load demand, to be determined by designer. Multiple studs connected independently of 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 – values in the table reflect installation into the wide face.
  9. 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 taken into account.