When are two nails required at each end of a splice in wood girder construction?

In wood girder construction, the requirement to use two nails at each end of a splice is specifically associated with using 10d nails. This practice is important for ensuring adequate strength and stability at the splice joint, which is a critical connection point in the structural assembly.

Using two nails helps distribute the load more evenly and provides added resistance against tensile forces that could pull the joint apart. The specific reference to 10d nails reflects industry standards and practices that have determined this nail size is optimal for splicing in certain applications, particularly those involving girder spans that require additional holding power.

In contrast, while larger nails like 16d may also be used in some situations, they typically do not require the same specification regarding the number of nails per splice as 10d nails do. The answer focusing on "any size nails" does not take into account the distinct specifications that vary according to the size of the nail being used. The reference to framing members longer than 8' is relevant in structural considerations but does not pinpoint a specific nail size requirement, which makes the answer less accurate. Thus, the importance of nail size in conjunction with splicing practices is best highlighted by the choice regarding 10d nails.