Axial compressive behaviors of the curved steel-plate composite walls with small curvature radius-to-section thickness ratio

Curved steel-plate composite (SC) walls are widely used in nuclear engineering due to their advantages in seismic performance and modular construction. This study tested the axial compression performance of five curved SC wall specimens and three flat SC wall specimens by considering the effects of the curvature radius-to-section thickness ratio (R/T) and connector spacing-to-steel plate thickness ratio (b/t). The tested results show that the steel plates in curved SC walls with small R/T (R/T < 20) are less prone to buckle than those in flat SC walls. Increasing R/T and b/t will reduce the axial compression capacity of the SC wall, also causing the earlier buckling of the steel plates. The simulation parametric analysis, conducted using the validated finite element model, reveals that R/T and b/t within a broader scope are not independent in their effects on curved SC walls. As b/t increases, reducing R/T leads to a more significant improvement in the axial compression performance of curved SC walls. Increasing the initial geometric defects decreases the steel plate buckling stresses but has little effect on the compression capacity of curved SC walls. Prediction methods are developed to determine the buckling stress and the axial compressive capacity of SC walls by considering the effect of curvature, which is applicable to both flat SC walls and curved SC walls with small R/T.