AutoTight® by Commins
Manufacturing, Inc.
The Continuous Rod Holdown System
  

Commins AutoTight® Rod Holdown System
 

Organizing the Runs
Specifying the Rod Size

Calculate the Differential Load
 Specifying the AutoTight® Components

What is it?

The AutoTight® Rod Holdown System is the premier low-cost structural holdown system. It uses threaded rod, steel plates and the AT Auto Take-Up™ to properly tie buildings down for lateral and uplift loading. The AT Auto Take-Up expands and keeps the building tight as the building shrinks, settles and moves. AutoTight® installs faster than the competition.

To specify the AutoTight® system the following steps are key:
Gather the pertinent structural information.
Organize and group the loads and runs in a table.
Specify the rod size based on the loads
Calculate the Differential Load for each level
Specify the required components, rod, plates, take-up devices

Key Structural Information:


1. Uplift force-Cumulative and per floor. Determine the uplift force on a level-by-level basis. Add the loads together to determine the required rod size. This will is used for rod, take-up, and plate sizing.


2. Wood Material: Determine the wood species, grade and size to be used.

3. Building Standard: Specify the building standard to be used. Note any additional state, or local codes.
 
4. Wood Shrinkage: Specify the expected shrinkage per floor. Because of the many variables, (Species, Starting MC (Moisture Content), Ending MC, wood stack height) this can be difficult to do. Please see Appendix 1, Shrinkage Table for Wood Buildings, for guidance. Using this graph greatly simplifies shrinkage calculations. Call the factory for additional information.

5. Story Height: this is the ceiling height plus the floor height above, or the carpet-to-carpet distance.

6. Wall Width (4” or 6”) for each run, to help specify trimmers and bearing plates.

Next>>
Organizing the Runs
Specifying the Rod Size
Calculate the Differential Load
 Specifying the AutoTight® Components

Download - Specifying the AutoTight® System . pdf - (4 pages, 111.1k)

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Copyright 2005  Commins Manufacturing, Inc., Friday Harbor, WA 98250, Tel (360) 378-9484
 

AutoTight® Rod Holdown Systems and components are covered by one or more of the following U.S. Patents 6,390,747; 6,585,469; 6,625,945, other patents both foreign and domestic are pending.