Circular hollow stainless-steel tubes subjected to low-temperature eccentric compression loads

Abstract

To investigate the eccentric compression behaviours of circular hollow stainless-steel tubes (CHSSTs) at low temperatures, 12 CHSSTs using SS 30408 tubes were tested. The studied low temperatures (T) were 20, −30, −60, and −80℃ and four eccentricity ratios (e/r) of e/r = 0, 0.33, 0.72, and 1.00 were considered in the eccentric compression testing program. The tests show that alternative inward and outward local buckles occurred to CHSSTCs under axial compression whilst inward local buckles were observed in those eccentrically-loaded CHSSTCs. The low temperatures do not exhibit obvious influence on their failure modes and positions of local buckles. Decreasing T from 20 to −80℃ increases the ultimate compression capacities (Pu) of axially and eccentrically loaded CHSSTCs by about 20%. As the T reduces from 20 to −30, −60, and −80℃, the ultimate bending resistances of CHSSTCs tested at e/r = 1.0 are increased by 15%, 16%, and 17%, respectively. With the increasing e/r ratio from 0 to 0.33, 0.72, and 1.00, the Pu of CHSSTCs tested at −60℃ are reduced by 50%, 59%, and 66%, respectively. Different code equations were used to estimate the compression capacity of these eccentrically-loaded CHSSTCs. The CSM method offers the closest estimations on ultimate resistances of CHSSTCs tested at different low temperatures. The EC3, ANSI-370, and SEI/ASCE 8 provide close and much more conservative estimations on the low-temperature N-M interactions of CHSSTCs.