Experimental study and stability design of corrugated steel arches subjected to gradient hydrostatic pressure

This paper proposes the application of corrugated steel arches (CSAs) within semi-submersible foundations to withstand gradient hydrostatic pressure in deep-water environments. To elucidate the load transfer mechanisms and failure modes of CSAs, full-scale specimens were subjected to five-point radial gradient loading using a custom-designed apparatus. Subsequent finite element analyses were conducted to evaluate the effects of critical design parameters on the buckling capacity of CSAs. Finally, the in-plane stability factor ( φ ) and the interaction factor ( α ) were calibrated using nonlinear regression analysis. The findings demonstrate that the slenderness ratio dictates the buckling capacity of CSAs. As the slenderness ratio increases, the failure mode of the CSAs transitions from elastoplastic local buckling to global buckling. During the process from water entry to complete submersion, the radial displacement induced by initial gradient hydrostatic pressure accounts for up to 38.5% of the ultimate displacement at the S /4 section of the CSA. To fully exploit the material strength of the corrugated cross-section, maintaining a normalized axial force greater than 0.5, the design slenderness ratio be restricted to 80 or less. Furthermore, the global stability design equations were derived for CSAs subjected to combined compression and bending under gradient hydrostatic pressure.