Ultimate capacity of nailed connections for design of breakaway walls

This research was conducted in connection with a study of the behavior of w ood breakaway walls used in residential houses constructed on piles in coas tal 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 o ut to obtain ultimate strengths of nailed connections for four nail sizes w ith various combinations of side and main members under dry, wet, and cycli c wet/dry conditions. Static and impact-type loads were applied to determin e the connection strength under load rates that reflect those likely to be encountered in the field. The wet ultimate strength of nailed connections l oaded in shear is about 80 percent of that of dry specimens. The common pra ctice of estimating the ultimate nailed connections capacity by applying a factor of safety (generally equal to five) may lead to erroneous results.