Ultimate response of stainless steel continuous beams

• Currently plastic design is not allowed for stainless steel indeterminate structures.
• 18 Tests on 2-span continuous beams were performed.
• 13 Auxiliary tests on imply supported beams and material coupon tests were reported.
• Tested sections comprised austenitic RHS and lean duplex welded I-sections.
• The continuous strength method was extended to stainless steel indeterminate structures.

An experimental study of stainless steel continuous beams not susceptible to lateral torsional buckling is reported in this paper and the applicability of plastic design methods to such structures is considered. A total of 18 two-span continuous beams were tested. Three cross-section types – cold-formed square hollow sections (SHS), cold-formed rectangular hollow sections (RHS) and welded I-sections, and two material grades – austenitic EN 1.4301/1.4307 and lean duplex EN 1.4162, were considered. The geometric and material properties of the continuous beam test specimens were carefully recorded and supplemented by tests on simply supported specimens of the same cross-sections. The test specimens covered a wide range of cross-section slendernesses and two different loading positions were adopted. The experimental results were used to assess the degree of moment redistribution in indeterminate stainless steel structures and the applicability of both conventional and novel plastic design methods, including an extension of the continuous strength method (CSM). Comparisons indicated that conventional plastic design is applicable to stainless steel structures, while greater efficiency can be achieved by considering strain-hardening through the CSM.