Use and Care Manual

66
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Holdowns
Holdowns
MiTek
®
Product Catalog
PHD / DTB Holdowns
PHD predeected holdowns feature the predeected base, minimizing
deection while providing uplift resistance. Installs with screws
eliminating the need for predrilling and potential fastener slip. No
thru bolts to countersink.
DTB-TZ is a light capacity holdown for single 2x installations.
Materials: See chart
Finish: G90 galvanizing; DTB-TZ – G-185 galvanizing
Codes: IBC, FL, LA
Installation:
• Use all specied fasteners. See Product Notes, page 18.
• Place the PHD over the anchor bolt, no washer is required.
Washer is required on DTB installations.
• Install with MiTek’s code evaluated WS15-EXT (1/4" dia. x 1-1/2"
long) and WS3 (1/4" dia. x 3" long) structural wood screws, which
are provided with the holdown.
• Tighten anchor bolt nuts nger tight to base plus 1/3 to 1/2
additional turns with a wrench.
• PHD Predeected Holdowns may be installed off sill plate
with no load reduction. Reference page 72 for more information.
• The design engineer may specify any alternate anchorage
calculated to resist the tension load for a specic application.
Anchorage exposure length should take the bearing plate
height of 1-5/8" into account, anchor bolt thread should
visibly extend above nut.
• If used to anchor a built-up post, such as a double 2x4, the post
component shall be designed to act as a single unit. Holdown fasteners
specied shall not be considered to attach multiple plies together.
• For anchorage options see STB/STBL Anchor Bolt section
on pages 49-50.
Typical PHD5A installation Typical DTB-TZ installation
PHD8 DTB-TZ
PHD5A
(PHD2A / PHD4A similar)
DF/SP S-P-F
Ref. No. W H D
CL
8
Qty
Dia.
Qty
Type
DTB-TZ DTT2Z 14 1-13/16 6 2-1/4 1-1/8 1 1/2 8 WS15-EXT 1835 1510 0.119
PHD2A HDU2-SDS2.5 14 3 7-3/4 2-5/8 1-3/8 1 5/8 6 WS3 3215 2700 0.155
PHD4A HDU4-SDS2.5 14 3 9-3/4 2-5/8 1-3/8 1 5/8 10 WS3 5215 4380 0.137
PHD5A HDU5-SDS2.5 14 3 11-11/16 2-5/8 1-3/8 1 5/8 14 WS3 6525 5480 0.135
PHD8 HDU8-SDS2.5 12 3-1/4 16-1/2 3 1-3/8 1 7/8 24 WS3 8185 6875 0.062
1) Allowable loads have been increased 60% for wind and seismic loads; no further increase shall be permitted.
2) The designer must specify anchor bolt type, length, and embedment.
3) Deflections are derived from static, monotonic load tests of devices connected to DF-L wood members with specified fasteners.
4) The designer shall consider the effect of compression, bearing, tension, and combined bending due to device eccentricity when applicable.
5) The PHD/PHDA may be elevated off the sill and may increase deflection. Reference page 72 for more information.
6) MiTek's WS15-EXT (1/4" dia. x 1-1/2" long) and WS3 (1/4" dia. x 3" long) structural wood screws are included with holdowns.
7) For PHD holdowns, minimum post thickness is 3". Consult MiTek for installations less than 3".
8) "CL" denotes the distance between the post and center of the anchor bolt.
Deflection
Δ (in)
at 160%
3,5
Corrosion
Finish
IBC,
FL,
LA
MiTek USP
Stock No.
Steel
Gauge
Dimensions (in) Fastener Schedule
Allowable Loads (Lbs.)
1,4,7
Tension
160%
Tension
160%
Anchor
Bolts
2
Screws
6
D
D
CL
CL
H
W
W
1-5/8"
Corrosion Finish
Stainless Steel Gold Coat
HDG Triple Zinc
Corrosion Finish Stainless Steel Gold Coat HDG Triple Zinc
Corrosion
Finish
Stainless Steel
Gold Coat
HDG
Triple Zinc
H
D
CL
W
H