WITHDRAWAL STRENGTH OF RING-SHANK NAILS EMBEDDED IN SOUTHERN PINE LUMBER

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.