AutoTight Tie-Down Systems

                      Commins Manufacturing Inc.        360-378-9484

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  Shrinkage Compensators, Delta R, and Shear Wall Performance
(5 minutes)

A video describing the Shear Wall performance formula and how it should be used.
Demonstrates the superior performance of the AutoTight shrinkage compensation devices.

Top_of_Page Delta R is Looseness
(3 minutes)

A video demonstrating the looseness of ratchet style shrinkage compensation devices and comparing them to the tightness of the AutoTight shrinkage compensation devices.

For a more detailed discussion of what Delta R is and why it is important.
 Read a PDF of this paper - (7 pages - 460 kb)

Top_of_Page  AutoTight Squishy Block Demo Video
(90 seconds)

squeeze block

The AT Squishy Block Demo is a hands on display used for demonstrating ease of use, simplicity and quality of the Automatic Take-Up Device (AT).
Read Squishy Block Instructions.pdf - (1 page - 140kb)

Top_of_Page Lateral Performance of Loose Shear Walls
(6 minutes)

loose shearwall

A demonstration of how different holdown systems effect shear wall performance.
Wood shear walls are designed to withstand the high lateral loads that occur during an earthquake or hurricane.
A key to maintaining the performance of the shear walls in a structure is the holdown system and shrinkage compensation devices.
As the wood structure shrinks and settles, up to one half inch (½”) per floor or more, the excessive looseness will lead to shear wall failure.
Tests have shown that as little as three-sixteenths of an inch (3/16”) of looseness can reduce the strength of a wood shear wall by 40%.

For a more detailed discussion of shrinkage backlash and shrinkage compensators.

Read a PDF of this paper - (2 pages - 500 kb)

Acrobat Reader is required to view some of the material.

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icces logoladbs logo 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.