Ring-shank nails are used extensively in post-frame construction due t
o their superior performance, yet surprisingly little testing has been
done on nail sizes above 12d. Experience in the post-frame industry s
uggests that published allowable design values for ring-shank nails ma
y be overly conservative and need revision. The goal of the research r
eported herein was to characterize the withdrawal strength of ring-sha
nk nails embedded in Southern Pine lumber Three sizes of galvanized an
d ungalvanized (bright) ring-shank nails from two manufacturers were s
tudied. Ring-shank nails had approximately twice the withdrawal resist
ance of smooth-shank nails of the same diameter Galvanizing slightly r
educed withdrawal strength (approximately 8%) due to partial filling o
f the threads. Nail head pull-through was studied as a possible failur
e mode. Even allowing for galvanizing and head pull-through, strong ev
idence is presented for increasing withdrawal design values for ring-s
hank nails.