Slide 62 of 67
Notes:
- Which nails should you use?
- Current building code accepts altered heads, but should you use them?
- The figure shows a plywood shear wall that failed at the panel edge which had clipped nail head on it
- Failure occurred by punching through at the nail head
- Use full nail heads
- Partial head nail failure is a common problem, seen in many buildings after Northridge
- Other failures after the Northridge Earthquake showed failure by withdrawal of the nail itself it some cases
- In addition to earthquake evidence, tests show that shear walls with 8d casing nails are only 62 percent as strong as ones with 8d box nails.
- This is because the head area of the casing nail is only 27 percent of the box nail, even though the shank diameters of the two nails are the same.
- So we know: Smaller head areas provide smaller shear wall strengths.
- We have talked about the types of nails to use
- Now let’s talk about how to properly install nails to maximize the strength of the shear wall during an earthquake.
