M+K’s collaborative research with University of California, San Diego has officially been published in the Journal of Building Engineering!
The study validates our initial hypothesis regarding minimum end distance requirements for nails at sheathing splices used in uplift resistance—an issue that has long lacked clarity in industry standards.
Background
Our research goal was to determine the minimum end distance required to achieve full nail capacities at sheathing splices for uplift resistance—critical for modern panelized construction practices.
The current uplift provisions in the Special Design Provisions for Wind and Seismic (SDPWS) by the American Wood Council (AWC) require:
- ¾” end distance for single nails
- ½” end distance for staggered double rows
These thresholds are significantly more conservative than those found in Chapter 12 of the National Design Specification for Wood Construction (NDS), which bases nail capacity on fastener diameter:
- Full capacity: 4 × diameter
- 50% capacity: 2 × diameter
For example:
- 8d nails (0.131” diameter) → Full: 0.524”, 50%: 0.262”
- 0.113” nails → Full: 0.452”, 50%: 0.226”
With the rise of panelized construction, splicing sheathing on single sole plates or top plates—rather than using flat blocking—has become increasingly common. Yet, the uplift requirements in SDPWS lacked supporting test data or commentary from AWC when we previously reached out.
What We Found
Our research confirms that the SDPWS uplift end distance requirements are not based on empirical testing. The published study provides much-needed clarity and supports more efficient design practices without compromising structural integrity.
The full article is now available in the Journal of Building Engineering. Read the full article here.
Huge thanks to the UCSD team and everyone at M+K who contributed to this effort. This is a meaningful step forward in aligning code provisions with real-world construction practices.