Experimental Characterization of Manufactured Home Roof-to-Wall Connections under Cyclic Loading: Implications for Wind Design

Abstract

Manufactured homes (MHs) are highly vulnerable to damage during extreme winds, with roof-to-wall (RTW) connections identified in post-storm assessments conducted in Wind Zones II and III as being critically susceptible. This study experimentally evaluates seven RTW connection configurations using steel straps and various fastener arrangements. These configurations are commonly specified for use in Wind Zones II and III, as defined by the US Department of Housing and Urban Development (HUD). The configurations were derived from manufacturer structural drawings that specify different capacity requirements and fasteners counts for RTW connections located on different sides of the structure. A total of 97 tests, including both monotonic and cyclic tests, were conducted. The results reveal that the evaluated sidewall connections failed to meet the design demands of both HUD and ASCE/Structural Engineering Institute (SEI) 7-22, evidencing significant capacity shortfalls. Staggered fastener configurations improved performance by mitigating premature row-splitting, particularly in nailed connections. Strap rupture emerged as the dominant failure mode in sidewall connections, indicating that current detailing fully mobilizes strap capacity with little to no reserve. Ductility, initial stiffness, cumulative energy dissipation, and strength degradation, were also quantified. The findings provide critical empirical data to advance understanding of wind-induced uplift behavior in MH RTW connections. They also lay a foundation for improved design provisions in HUD’s Part 3280, “Manufactured Home Construction and Safety Standards,” including new strap and fastener requirements for RTW connections.