Ultimate capacity of nailed connections for design of breakaway walls

This research was conducted in connection with a study of the behavior of wood breakaway walls used in residential houses constructed on piles in coastal areas in the United States. The design of a breakaway wall, which must collapse under prescribed loading, requires accurate knowledge of ultimate strengths of fasteners and materials. Laboratory experiments were carried out to obtain ultimate strengths of nailed connections for four nail sizes with various combinations of side and main members under dry, wet, and cyclic wet/dry conditions. Static and impact-type loads were applied to determine the connection strength under load rates that reflect those likely to be encountered in the field. The wet ultimate strength of nailed connections loaded in shear is about 80 percent of that of dry specimens. The common practice of estimating the ultimate nailed connections capacity by applying a factor of safety (generally equal to five) may lead to erroneous results.