Uplift Capacity of Polyurea-Coated Light-Frame Rafter to Top Plate Connections

Abstract

This paper demonstrates the potential for using field-applied structural coatings to reinforce traditional framing members and standard building ties, thereby providing an improved and continuous foundation to roof load pathway. Tension tests were performed on light-frame rafter to top plate connections, some of which were reinforced with a hurricane tie, to establish how much of a difference a polyurea coating made as the joints between the stud and top plate, and top plate and rafter, were loaded to failure. The tests indicate that polyurea provides universal strengthening compared with hurricane ties with the added advantage that members and joints can be protected from a multitude of threats, including corrosion attributable to moisture, damage attributable to flood; and, with self-extinguishing properties fire. The addition of the coatings allowed both unreinforced and reinforced configurations to withstand higher loads (200–400% more). In general, the polyurea delayed the onset of failure and significantly strengthened every configuration by increasing the amount of work/energy required to pull it apart; in some cases, by almost 800%.