Coupling Effects of Seam–Clip Connection of 360° High-Vertical Standing Seam Metal Roofs Under Wind Suction

The clip–seam connection in 360° high-vertical standing seam metal roofs (360DHVSSMR) exhibits pronounced nonlinear behavior under high wind uplift pressures, resulting in significant three-directional coupling effects among the vertical, transverse horizontal, and rotational degrees of freedom. These coupling effects arise from plastic deformation and geometric interaction within the seam–clip assembly and their physical interpretation of the coupling mechanisms remain insufficiently understood. To characterize and quantify such coupling behavior, a triaxially coupled elastoplastic spring formulation is employed to describe the interactive evolution of stiffness and plastic deformation in the seam–clip connection. A systematic calibration and validation framework is established based on component-level experimental tests of 360DHVSSMR. Uniaxial tensile tests corresponding to the vertical, transverse horizontal, and rotational responses are first conducted, and the parameters governing the coupled constitutive relationship are identified using the least-squares method. The calibrated formulation is then validated through independent uniaxial tensile tests and full-scale wind uplift tests. The results demonstrate that the coupled elastoplastic spring model can accurately reproduce the mechanical behavior of the seam–clip connection, with both displacement and force prediction errors controlled within 10%. In the simulation of the static wind resistance performance of the roof system, the displacement prediction error is further reduced from 31% to 11% compared with the conventional model. These results highlight the critical role of three-directional stiffness coupling in the wind-induced response of 360DHVSSMR.