As a former senior structural engineer turned software developer, I just wanted to comment regarding the glue +/vs nails. Although glue adds rigidity to the whole board, glue does not add strength, meaning their strength is not additive. The glue needs to fail in order for the nails to provide their function. In tension, the glue prevents two pieces from separating, and the nail just sits there not being engaged. In shear, the glue prevents two pieces of wood from sliding past each other and therefore prevent the nail from being engaged.