Compressive strength of concrete-filled stainless steel tube stub columns

Abstract

Concrete-filled stainless steel tube (CFSST) members combine the advantages of the outstanding corrosion resistance of stainless steel and the composite action in concrete-filled steel tube (CFST) system. However, accurate calculation methods for this type of structures are currently limited and research into CFSST members with hot-rolled stainless steel tubes are not available. In this paper, the compressive behavior of CFSST stub columns has been investigated through a comprehensive experimental and numerical program. A total of 18 specimens, including 9 concrete-filled austenitic stainless steel tube (austenitic CFSST) and 9 concrete-filled duplex stainless steel tube (duplex CFSST) stub columns, were tested under compression. The varying parameters in the experimental study included the thickness of the stainless steel tube and the strength of the concrete. Finite element (FE) models duplicating the tests were developed, which were subsequently used in parametric study to generate a wider range of data and to investigate the influence of the tube thickness and concrete strength on the ultimate capacities of CFSST stub columns. Based on the generated data, it was found that the current European and Chinese standards for concrete-filled carbon steel tubes underestimate the resistances of CFSST members significantly. To this end, new calculation methods developed based on these European and Chinese design rules have been proposed, which were shown to provide improved strength predictions for both the austenitic and duplex CFSST members.