Eccentric compression behaviour of high strength stainless-clad bimetallic steel circular hollow sections

Stainless-clad bimetallic steel combines high corrosion resistance with competitive material cost by using a high strength steel substrate, offering promising potential for marine and nearshore structures. This study investigates the structural behaviour and resistances of high strength stainless-clad bimetallic steel (HSSCBS) circular hollow section (CHS) stub columns under eccentric compression through laboratory tests and numerical simulations. The tests included measurements of material properties and initial local geometric imperfections as well as eccentric compression tests on twelve HSSCBS CHS stub column specimens, considering three clad ratios and four levels of initial loading eccentricity. The material properties of HSSCBS were found to align with the rule of mixture. The full load−deformation histories of the test specimens were analysed. Finite element models validated against the experimental results were then used for parametric studies to expand the data pool. Then, the applicability of the design interaction curves for carbon steel or stainless steel CHS members specified in European and American codes was evaluated for HSSCBS CHS stub columns based on the experimental and numerical results. The evaluation revealed that the existing design interaction curves are generally conservative, mainly due to the insufficient exploitation of the material strength. Accordingly, an improved design method based on the continuous strength method was proposed for eccentrically loaded HSSCBS CHS stub columns, yielding a high level of accuracy and consistency in failure load predictions.