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HDQ8/HHDQ Holdown
Installation
The HHDQ series of holdowns combines low deflection and high loads with ease of installation. The unique seat design of the HDQ8 greatly minimizes deflection under load. Both styles of holdown employ the Strong-Drive® SDS screws which install easily, reduce fastener slip and provide a greater net section when compared to bolts. They may be installed either flush or raised off the mudsill without a reduction in load value.
Special Features:
- Uses SDS screws which install easily, reduce fastener slip, and provide 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: HDQ8—7 gauge; HHDQ—Body: 7 gauge, washer: 1/2" plate
Finish: HDQ8—Galvanized; HHDQ—Simpson Strong-Tie® gray paint
Installation:
- Use all specified fasteners. See General Notes.
- For use in vertical and horizontal applications.
- No additional washer is required.
- To tie multiple 2x members together, the Designer must determine the fasteners required to join members without splitting the wood.
- 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.
- 5/8" of adjustability perpendicular to the wall.
HHDQ11/14: - No additional washer is required.
- HHDQ14 requires a heavy hex anchor nut (supplied with holdown)
HDQ8:
For holdowns, per ASTM
test standards, anchor bolt nut
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.
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These products are available with additional corrosion protection. Additional products on this page may also be available with this option, check with Simpson Strong-Tie for details.
- Allowable loads have been increased for earthquake or wind 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. Tabulated loads are based on a minimum 3 1/2" wide post (in a 3 1/2" wall). Post may consist of multiple members provided they are connected independently of the holdown fasteners. See Post Capacities for common post allowable loads.
- Tension values are valid for holdowns flush or raised off of sill plate.
- Deflection at Allowable Tension Load includes fastener slip, holdown deformation and anchor rod elongation for holdowns installed up to 6" above top of concrete. Holdowns may be installed raised up to 18" above top of concrete with no load reduction provided that additional elongation of the anchor rod is accounted for.
- Tabulated loads may be doubled when holdowns are installed on opposite sides of the wood member provided either the post is large enough to prevent opposing holdown screw interference or the holdowns are offset to eliminate screw interferences.
- Noted HHDQ14 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).
- HDQ and HHDQ holdowns installed horizontally can achieve compression loads with the addition of a standard nut on the underside of the load transfer plate. Refer to ICC-ES ESR-2330 for design values. HDQ8 requires a standard nut and BP7/8-2 (sold separately) load washer on the underside of the holdown for compression load. Design of anchorage rods for compression force shall be per the Designer.
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top Code Reports (PDFs): | Legacy Reports | |||||||
| IAPMO UES ER | ICC-ES ESR | CITY OF LOS ANGELES | STATE OF FLORIDA | ICC-ES NER | ICC-ES ER | ICC-ES ES | |
| HDQ8-SDS3 | ESR-2330 / ESR-2523 * | RR25720 | FL10441 | ||||
| HHDQ | See specific model numbers for code listings. | ||||||
| HHDQ11-SDS2.5 | ESR-2330 / ESR-2523 * | RR25720 | FL10441 | ||||
| HHDQ14-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
next topDrawings: To download drawings, right-click or Ctrl-click on the link, then choose "Save Target As..."Download the Simpson Strong-Tie® AutoCAD® Menu, which allows you to insert Ortho views directly into your AutoCAD drawing.
ORTHOGRAPHIC | PERSPECTIVE | |
| HHDQ | None for this model | None for this model |
| HHDQ11 |
HHDQ11: DWG | DXF
HHDQ11 front view: DWG | DXF HHDQ11 left view: DWG | DXF HHDQ11 right view: DWG | DXF HHDQ11 top view: DWG | DXF |
None for this model |
| HHDQ14 |
HHDQ14: DWG | DXF
HHDQ14 front view: DWG | DXF HHDQ14 left view: DWG | DXF HHDQ14 right view: DWG | DXF HHDQ14 top view: DWG | DXF |
None for this model |
| HHDQ8 | None for this model | None for this model |
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Connectors Installed on SCL Columns, Limit States Design, for Canada only