Embodiments of the invention include structural decking systems with at least a four-layered seam and methods for manufacturing and assembling structural decking systems with at least four-layered seams. The decking panels may be provided with an edge having an exposed “male lip” with two layers, and an opposite edge having a “female lip” with two layers. Individual panels may be coupled together by placing the female lip of a first panel over the male lip of an adjacent panel, thus creating an unjoined seam. In order to couple the panels together, the panels may be secured through various couplings configurations. The couplings may be formed by deforming, cutting, and/or welding the seam. Not only do the couplings help prevent vertical separation between adjacent panels, the couplings minimize lateral shifting along the seam, and ensure a desired level of shear strength in the seam and across the structural decking system.