HDC Concentric Holdown

The unique design of the HDC holdowns eliminate eccentricity. They install with Simpson Strong-Tie® Strong-Drive® screws (SDS) (included) to reduce slip and provide a greater net section area of the post compared to bolts.

Material: 10 gauge strap.

Finish: Galvanized strap, aluminum base.

Installation:

Use all specified fasteners. See General Notes.
Install on concrete.
For use in vertical and horizontal applications.
Sized for 2-2x, and 4x. Center 2-2x posts on holdown.
Uses SDS screws supplied with the holdowns to ensure proper fasteners are used.
Slot in the seat allows for 3/8" of adjustment perpendicular to plate.
Cut washer required between base and anchor nut. For HDC5 models use a standard cut washer. For HDC10 models use narrow cut washer with outside diameter of 1 3/4".
Witness slot in the base to inspect the nut.
Maximum anchor bolt height above concrete is 2 1/8".
To tie multiple 2x members together, the Designer must determine the fasteners required to join members to act as one unit without splitting the wood. See SDS Screw information.
Aluminum standoff cannot be in contact with pressure-treated wood.
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 not to over-torque the nut. Impact wrenches should not be used.

The Designer must specify anchor bolt type, length and embedment. See SB Anchor Bolts. Refer to Anchor Designer Software™ for ACI 318 for anchoring solutions.
Loads are based on static tests on wood studs, limited by the lowest of 0.125" deflection, test ultimate divided by 3, or the wood screw value.
Deflection at Highest Allowable Tension Load includes fastener slip, holdown elongation, and anchor bolt elongation (L = 6"). Additional elongation of anchor bolts shall be accounted for by the Designer when holdowns are raised higher than 6".
The HDC's will be limited by wood compression capacity if installed on a sill plate. HDC5/22 and HDC10/22 will achieve an allowable load of 4005 lb. on a DFL plate. HDC5/4 and HDC10/4 will achieve an allowable load of 4940 lbs. on a DFL plate, which does not take deflection into account. Full tension values apply when installed on a sill; deflection may be higher.
Higher values may be obtained when HDC is not placed at an edge or with f'_c concrete strength > 2500 psi.
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 shall be by Designer.

					Legacy Reports
	IAPMO ES ER	ICC-ES ESR	CITY OF LOS ANGELES	STATE OF FLORIDA	ICC-ES NER	ICC-ES ER	ICC-ES ES
HDC	See specific model numbers for code listings.
HDC10/22-SDS2.5	No code listing: Please contact us for test data.
HDC10/4-SDS2.5	No code listing: Please contact us for test data.
HDC5/22-SDS2.5	No code listing: Please contact us for test data.
HDC5/4-SDS2.5	No code listing: Please contact us for test data.

Download the Simpson AutoCad Menu, which allows you to insert Ortho views directly into your AutoCAD drawing.

	ORTHOGRAPHIC	PERSPECTIVE
HDC	None for this model	High Wind-Resistant Construction D87: Holdowns: Typical HDC Installation with 2-2x4 Studs: DWG \| DXF HDC: DWG \| DXF
HDC10/22-SDS2.5	None for this model	None for this model
HDC10/4-SDS2.5	None for this model	None for this model
HDC5/22-SDS2.5	None for this model	None for this model
HDC5/4-SDS2.5	None for this model	None for this model