Axial slenderness limits for austenitic stainless steel-concrete composite columns

The use of stainless steel in steel-concrete composite construction is an emerging topic considering the higher durability, corrosion resistance, and fire resistance as well as aesthetic benefits and ease of maintenance of stainless steel compared to carbon steel. In line with this, the present paper reports the results of a series of experimental and numerical investigations on the local and post-local buckling of austenitic stainless steel-concrete composite columns with an aim to propose axial slenderness limits as well as effective width/diameter formulae for these members. Such limits have not yet been established for stainless steel-concrete composite members in international design standards. Three section types, namely, concrete-filled box, concrete-filled circular, and partially-encased I-sections are thoroughly studied. The investigated columns include some of the largest and most slender stainless steel-concrete composite sections studied to date. The obtained results are compared with theory as well as approaches currently in use by international design standards. It is demonstrated that the codified slenderness limits developed for carbon steel-concrete composite columns cannot be directly used for the stainless steel counterparts and modifications are required. The modifications are recommended in light of the findings of the present study. In addition to axial slenderness limits, effective width/diameter formulae are also recommended for the studied section types. (C) 2019 Elsevier Ltd. All rights reserved.