When Simpson Strong-Tie set out to re-engineer their Strong-Drive® WSV Subfloor screw, the plan was to bring a code-evaluated, no-squeak, no-glue all screw replacement for sheathed horizontal wood-frame diaphragms to the market. We knew that these collated fasteners, which were designed for fast subfloor installation using the auto-feed Quik Drive® system, were going to be an ideal replacement for 8d and 10d nails. The only thing left to do was to prove it…
Tag: wood framing
Why Your NDS Nail Calcs Could Be Wrong. . .And What You Can Do About It
This week’s post was written by Bob Leichti, Manager of Engineering for Fastening Systems. Prior to joining Simpson Strong-Tie in 2012, Bob was an Engineering Manager covering structural fasteners, hand tools, regulatory compliance and code reports for a major manufacturer of power tools and equipment. Prior to that, Bob was a Professor in the Department of Wood Science and Engineering at Oregon State University. He received his B.S. and M.S. from the University of Illinois, and his M.S. and Ph.D. from Auburn University.
When test results don’t make sense, we start by eliminating causes of the problem. When our withdrawal test values came up low, we checked the load cell calibration, the specific gravity of the wood, the nail dimensions, even the units – everything was correct. So why were the nail withdrawal values so low? More wood, more nails, more tests – same results. Ultimately, we concluded that the withdrawal resistance of stainless-steel, smooth-shank nails is not well described by the withdrawal function in the 2012 NDS, section 11.2.3, equation 11.2-3.Continue Reading