Auto Tight Hold Down System

I was doing some further research into shear wall design and I though, what kind of bracing system will keep a shear wall rigid? Turns out there are many ways to brace a shear wall but this method caught my eye. Its called the Auto Tight Hold Down System. What happens over time, 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%. I though wow, for a location that experiences a high amount of earthquakes a year, these buildings keep getting weaker every year. Now this product is designed to compensate for the shrinkage and automatically tighten to keep the shear wall rigid. I have some pictures below of how the product is placed in a shear wall that I have taken from their website.




















Auto Tight Hold Down Website