HDU Holdown

HDU Holdowns are pre-deflected during the manufacturing process, virtually eliminating deflection under load due to material stretch. They use Simpson Strong-Tie® Strong-Drive® screws (SDS) which install easily and provide reduced fastener slip. Using SDS screws results in a greater net section, when compared to bolts, as no material is removed.

The HDU series of holdowns are designed to replace previous versions of the product such as PHD’s as well as bolted holdowns. The HDU2, 4 and 5 are direct replacements for the PHD2, 5 and 6, respectively.

For more information on holdown options, contact Simpson Strong-Tie.

Special Features:

Pre-deflected body virtually eliminates deflection due to material stretch.
Uses SDS screws which install easily, reduces fastener slip, and provides a greater net section area of the post compared to bolts.
SDS screws are supplied with the holdowns to ensure proper fasteners are used.
No stud bolts to countersink at openings.

Material: See table.

Finish: Galvanized.

Installation:

Use all specified fasteners. See General Notes.
For use in vertical and horizontal applications.
No additional washer required.
To tie multiple 2x members together, the Designer must determine the fasteners required to join the members to act as one unit without splitting the wood. See SDS Screw information.
See SB and SSTB Anchor Bolts for anchorage options.
SDS screws install best with a low speed high torque drill with a 3/8" hex head driver.
Refer to Anchor Designer Software™ for ACI 318 for anchoring solutions.

For holdowns, per ASTM test standards, anchor bolt nuts should be finger-tight plus 1/3 to 1/2 turn with a hand wrench, with consideration given to possible future wood shrinkage. Care should be taken to not over-torque the nut. Impact wrenches should not be used.

Allowable loads have been increased for wind or earthquake load durations with no further increase allowed; reduce where other load durations govern.
The Designer must specify anchor bolt type, length and embedment. See SB and SSTB Anchor Bolts. Refer to Anchor Designer Software™ for ACI 318 for anchoring solutions.
Structural composite lumber columns have sides that show either the wide face or the edges of the lumber strands/veneers. Values in the tables reflect installation into the wide face. See technical bulletin T-SCLCOLUMN for values on the narrow face (edge).
Post design by Specifier. Allowable load values are based on a minimum wood member thickness in the direction of the fastener penetration. Posts may consist of multiple 2x members provided they are designed to act as one unit independently of the holdown fasteners. Holdowns shall be installed centered along the width of the attached post.
Tension values are valid for holdowns flush or raised off of sill plate.
Deflection at Highest Allowable Tension Load includes fastener slip, holdown elongation, and anchor bolt elongation (L = 6"). Additional elongation of anchor bolts longer than 6" shall be added to holdown deflection.
Tabulated loads may be doubled when the HDU is installed on opposite sides of the wood member provided either the post is large enough to prevent opposing holdown screw inferference or the holdowns are offset to eliminate screw interferences.
Noted HDU14 allowable loads are based on a 5 1/2" wide post (6x6 min.).All other loads are based on 3 1/2" wide post minimum.
Requires heavy hex anchor nut to achieve tabulated loads (supplied with holdown).

					Legacy Reports
	IAPMO ES ER	ICC-ES ESR	CITY OF LOS ANGELES	STATE OF FLORIDA	ICC-ES NER	ICC-ES ER	ICC-ES ES
HDU	See specific model numbers for code listings.
HDU11-SDS2.5		ESR-2330 / ESR-2523 *	RR25720	FL10441
HDU11-SDS2.5		ESR-2330 / ESR-2523 *	RR25720	FL10441
HDU14-SDS2.5		ESR-2330 / ESR-2523 *	RR25720	FL10441
HDU14-SDS2.5		ESR-2330 / ESR-2523 *	RR25720	FL10441
HDU2-SDS2.5		ESR-2330 / ESR-2523 *	RR25720	FL10441
HDU4-SDS2.5		ESR-2330 / ESR-2523 *	RR25720	FL10441
HDU5-SDS2.5		ESR-2330 / ESR-2523 *	RR25720	FL10441
HDU8-SDS2.5		ESR-2330 / ESR-2523 *	RR25720	FL10441

* ESR-2523 is an Index of many of Simpson Strong-Tie Stamped and Welded Cold-formed Steel Products for Wood or Cold-formed Steel Construction

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	ORTHOGRAPHIC	PERSPECTIVE
HDU	None for this model	None for this model
HDU11-SDS2.5	None for this model	None for this model
HDU11-SDS2.5	None for this model	None for this model
HDU14-SDS2.5	None for this model	None for this model
HDU14-SDS2.5	None for this model	None for this model
HDU2-SDS2.5	None for this model	None for this model
HDU4-SDS2.5	None for this model	None for this model
HDU5-SDS2.5	None for this model	None for this model
HDU8-SDS2.5	None for this model	None for this model