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RTUD Ratcheting Take-Up Device

RTUD

Strong-Rod™ ATS Components

This product's information may differ depending on the category of use. You are currently viewing details related to Strong-Rod™ ATS Components. You can also view product information related to the category: Strong-Rod™ URS Components

The RTUD ratcheting take-up device is a cost-effective shrinkage compensation solution for continuous rod systems. The RTUD is now code-listed for use with rod systems to ensure highly reliable performance in a device that allows for unlimited shrinkage. Once the RTUD is installed, a series of internal threaded wedges enable the device to ratchet down the rod as the wood structure shrinks, but engage the rod in the reverse direction when under tensile loading. Continuous engagement is maintained on the rod at all times by the take-up device, enabling the rod system to perform as designed from the time of installation.

Key Features

  • Maintains rod-system tightness, allowing it to perform as designed
  • Pass-through design provides unlimited shrinkage compensation
  • Available for 1/2", 5/8" and 3/4" diameter threaded rod
  • Fastens easily to the wood plate with the BPRTUD bearing plate and (2) 8dx1 1/2" nails (minimum) or (2) #9x1 1/2" Strong-Drive® SD Connector screws (not included)
  • 1.33-degree rod offset (1 3/4" max) allowed per floor
  • Very minimal force required to allow rod to pass through take-up device to mitigate rod buckling during wood shrinkage

Material

RTUD—ASTM A732; BPRTUD—3 Gauge

Finish

RTUD—Corrosion-resistant finish; BPRTUD—None

Installation

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 Connector screws.

Design Instructions

  1. 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.
  2. 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.
  3. 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.

Related Literature

Load Tables

RTUD Technical Data
Model No. Threaded
Rod Dia. (in.)
Dimensions (in.) Allowable Load
(lbs.)
Seating Increment ΔR
(in.)
Deflection at
Allowable Load ΔA
(in.)
Compatible
Bearing Plates
ATS/URS
Length Width Height
RTUD3 3/8 2 3/8 1 1/4 15/16 3,335 0.053 0.015 BPRTUD3-4 URS
RTUD4 1/2 2 3/8 1 1/4 15/16 6,665 0.048 0.011 BPRTUD3-4 ATS/URS
RTUD4B 1/2 2 3/4 1 1/2 1 9,210 0.0396 0.003 BPRTUD3-4B ATS/URS
RTUD5 5/8 3 7/8 2 1 3/8 14,495 0.056 0.007 BPRTUD5-6* ATS/URS
RTUD6 3/4 3 7/8 2 1 3/8 20,830 0.057 0.010 BPRTUD5-6* ATS/URS
  1. Allowable loads are for RTUD only. The attached components must be designed to resist design loads in accordance with the applicable code
  2. Thread specification for threaded rod must be UNC Class 2A, in accordance with ANSI/ASME B1.1.
  3. No further increase in allowable load permitted.
  4. RTUD3-4 fastens to the wood plate with the BPRTUD bearing plate and (2) 8dx1 1/2" or 2 1/2" nails or (2) #9x1 1/2" or 2 1/2" Strong-Drive® SD Connector screws. RTUD5-6 fastens to the wood plate with the BPRTUD bearing plate and (2) 8dx2 1/2" nails or (2) #9x2 1/2" Strong-Drive SD Connector screws. (Fasteners not included.)
  5. The specified minimum tensile strength, Fu, for the threaded rod must not exceed 80 ksi for the RTUD3, 90 ksi for the RTUD4, and 125 ksi for RTUD4B, RTUD5 and RTUD6.

*Indicate the compatible BPRTUD5-6 on design plan. Refer to BPRTUD table below.

BPRTUD Technical Data
Model No. Length
(in.)
Width
(in.)
Thickness
(ga.)
Allowable Loads (lbs.) (160)2
DF SP HF SPF
BPRTUD3-4 3 3 3 ga. 5,965 5,390 3,865 4,055
BPRTUD3-4B 3 1/2 3 3 ga. 6,415 5,975 4,475 4,700
BPRTUD5-6A 4 1/2 3 3 ga. 7,080 6,575 5,175 5,355
BPRTUD5-6B 5 1/2 3 1/2 in. 10,295 9,305 6,670 7,000
BPRTUD5-6C 7 1/2 3 3/4 in. 13,385 12,100 8,675 9,105
  1. No further increase in allowable load permitted.
  2. Bearing plate loads based on rod diameter plus 1/4"-diameter drilled hole through wood plate below steel bearing plate. Reduce allowable load per code for larger holes.

Code Reports

Part IAPMO UES ER ICC-ES ESR City of Los Angeles State of Florida
BPRTUD No code listing. Please contact us for test data.
BPRTUD3-4 No code listing. Please contact us for test data.
BPRTUD5-6 No code listing. Please contact us for test data.
RTUDSee specific model numbers for code listings.
RTUD3 ESR-2320 RR25643 FL10007
RTUD4 ESR-2320 RR25643 FL10007
RTUD5 ESR-2320
RTUD6 ESR-2320

Drawings

Part Orthographic Perspective
BPRTUDNone None
BPRTUD3-4None None
BPRTUD5-6None None
RTUDNone None
RTUD3
RTUD3 front view
DWG DXF
RTUD3 left view
DWG DXF
RTUD3 top view
DWG DXF
RTUD3
DWG DXF
RTUD4
RTUD4 front view
DWG DXF
RTUD4 left view
DWG DXF
RTUD4 top view
DWG DXF
RTUD4
DWG DXF
RTUD5None None
RTUD6None None