Research Status and Future Prospects of Concrete-filled Stainless Steel Tube Members

Concrete-filled stainless steel tubular (CFSST) members combine the structural characteristics of concrete-filled steel tubular members with the inherent corrosion resistance of stainless steel. Representing a class of nonlinear materials, stainless steel significantly differs in mechanical behavior from conventional steel. This divergence becomes particularly evident when design specifications traditionally applied to concrete-filled steel tube structures are directly used for stainless steel counterparts, often leading to an overly conservative estimation of the steel tube section's strength due to the overlooked strain hardening and pronounced nonlinearity of stainless steel. This study embarks on a comprehensive review, encapsulating the research progress in the static performance, interface bond behavior, and seismic resilience of CFSST members. It underscores that the predominant focus of current research lies in static performance, with a special emphasis on methodologies for calculating the axial compressive bearing capacity of cross-sections. Meanwhile, it is observed that research in the realms of interface bonding and dynamic performance is still nascent. A critical observation of the study is the inadequate exploration of the strain hardening phenomenon in stainless steel within existing literature. Consequently, this paper scrutinizes and augments the application of the continuous strength method, paving the way for future research endeavors aimed at a more nuanced and accurate depiction of the mechanical performance of CFSST members, thereby enhancing their application efficacy in structural design.