Strength of plywood joints with overdriven nails

The strength of plywood joints with overdriven sheathing nails is discussed in this paper. Plywood joints constructed with 15/32-inch plywood sheathing attached to 2 by 4 wood members using 8d common or 8d cooler nails were tested using the sequential phased displacement (SPD) loading protocol. Four nail-drive depths were investigated using cooler nails: flush driven, 1/16 inch overdriven, 1/8 inch overdriven, and 3/16 inch overdriven. Only flush-driven common nails were investigated. The results indicate that the stiffness of plywood joints using cooler nails increases from 10 to 21 percent with an increase in nail-drive depth. However, the strength decreases 11 percent for a 3/16-inch overdriven depth. Moreover, with an increase in nail-drive depth, the displacement capacity decreases from 38 to 77 percent, and energy dissipation decreases from 16 to 74 percent. Plywood joints using flush-driven common nails have similar mechanical properties compared to plywood joints using flush-driven cooler nails, except joints using common nails have 36 percent less displacement capacity.