Final answer:
For joist framing over a bearing support, 16d common nails that are at least 3 1/2 inches long are typically used, which corresponds to the general construction practices and building codes.
Step-by-step explanation:
When nailing joist framing from opposite sides over a bearing support, it's crucial to choose the right type of nails to ensure the structure's stability and safety. The choice of nails depends on the construction codes and the specific requirements of the project, such as the size and weight of the joists being supported. In general, common practices suggest using nails that are long enough to penetrate through the joist and well into the bearing structure, typically at least 3 1/2 inches for 2x framing material. These nails should be of a thickness that is appropriate to resist the sheer force that the connection will experience, often 16d (penny) common nails are used for framing applications.
It's essential to consider the shearing effect and ensure the nails used can withstand the forces applied. Calculations similar to those for determining the mass a nail can support when hanging a picture, as illustrated in FIGURE 5.17, may be relevant for understanding the shearing effect on nails used in framing. However, for construction projects, always consult local building codes and a structural engineer to determine the precise requirements for your specific project.