Specification
800-999-5099
www.strongtie.com
This flier is effective until December 31, 2014, and reflects information available as of October 1, 2012.
This information is updated periodically and should not be relied upon after December 31, 2014; contact
Simpson Strong-Tie for current information and limited warranty or see www.strongtie.com.
©2012SimpsonStrong-TieCompanyInc.•P.O. Box 10789, Pleasanton, CA 94588
F-RTUD12 10/12 exp. 12/14
RTUD Ratcheting Take-Up Device
RTUD Installation and Design Notes for
Simpson Strong-Tie
®
Rod Systems
1. The RTUD3 or RTUD4 must be installed on top of the BPRTUD3-4
bearing plate and fastened through the bearing plate to the wood
top plates or bottom plate with (2) 8dx1
1
⁄2" min. nails or (2)
#9x1
1
⁄2" Strong-Drive
®
SD structural-connector screws.
2. In order for the RTUD to ratchet properly, rods must be
installed at less than 1.33° from vertical or 1
3
⁄4" offset per
floor whichever is less.
• Carefully align the holes through the wood floor system
so they align vertically (through top plates, floor sheathing
and bottom plate). If misaligned, the rod will be installed
at an angle that may bind on the wood framing.
3. The RTUD compensates for an unlimited amount of wood
shrinkage provided there are no obstructions to the travel
of the RTUD along the length of the threaded rod and
adequate clearance above the RTUD. Holes in the wood
top or bottom plates must be oversized adequately to
allow the all-thread rod to freely pass through. The more
vertical the rod, the smaller the possible hole diameter.
• The Designer should verify maximum hole size in plates
to ensure there is enough shear capacity – for drag and
chord forces in plates – and bearing capacity due to area
of bearing plate compared to area of wood plate beneath.
4. Simpson Strong-Tie does not require the all-thread rod be
pre-tensioned when used with RTUD. The rod will normally
feel “loose.” However, as long as the RTUD is firmly seated
on the bearing plate, and the rod can move freely through
the lumber and RTUD, the system is properly installed.
Why Use a Take-Up Device?
In order for rod systems to perform properly,
compensators for shrinkage within the wood
structure must be used. Without take-up devices,
gaps can occur between wood members and key
elements of the rod system, such as nuts and
bearing plates (see photo at left). This can result in
excessive movement during a seismic or wind event.
Want to estimate the shrinkage
in a structure?
Visit www.strongtie.com/shrinkcalc
for our free shrinkage calculator web app.
1¾" maximum or
1.33° offset per floor
(whichever is less)
1¾" maximum
offset per floor
C
L
at plumb of
anchor below
C
L
C
L
RTUD & plate
Threaded Rod
Coupler
C
L
at plumb of
anchor below
Coupler
Anchor bolts
as specified