Resistance of Wood and Plywood to Embedment of Fastener Heads

摘要

The bearing strength of wood and plywood under fastener heads was determined so that proper designs could be established for ship bulkheads. Fastener heads of flathead wood screws, bolts, and bolts with washers were evaluated in dry Douglas-fir, southern yellow pine, and Douglas-fir plywood. The maximum resistance to head embedment of these fasteners was about 1,000 pounds per inch of fastener head perimeter. Loads at 0.10-inch embedment were 40 to 50 percent and at 0.05-inch embedment were about one-third of maximum loads. Thicker material was found to have greater embedment resistance than thinner material, and plywood was found to be comparable to wood in its resistance to fastener embedment. Although this investigation was specifically related to ship construction, the data can be useful in other construction design, such as anchorage of building framework to foundation structures. (Author)