Experimental investigation of eccentrically compressed stainless steel columns with constraints in fire

To study the behaviour reaction and failure mechanism of stainless steel columns in fire, a series of fire tests were performed on the eccentrically compressed columns with constraints, based on S30408 stainless steel. 7 specimens were used to investigate the effects of the load ratio n, eccentricity e and axial constraint stiffness ratio β on the fire-resistance performance of eccentrically compressed stainless steel columns. The failure process and failure modes of stainless steel columns in fire were revealed. The test phenomena, heating curve, deformation curve and buckling temperature were obtained. The test results show that the load ratio n (n = 0.22-0.35), eccentricity e and axial constraint stiffness ratio β (β = 0.0458 and 0.0495) are the key factors that determine the fire-resistance performance of eccentrically compressed stainless steel columns with constraints. The larger the load ratio n, eccentricity e and axial constraint stiffness ratio β are, the lower the buckling temperature of the specimen. There are two main types of failure modes of eccentrically compressed stainless steel columns with constraints in fire: the first is the overall buckling mode and the second is the local-overall interaction buckling mode. The failure modes depend mainly on the section dimensions and the section type of the stainless steel column. The process of bearing capacity of eccentrically compressed stainless steel columns with constraints in fire goes through two stages: the prebuckling stage and the post-buckling stage. It takes times for the specimen to progress from the buckling state to the ultimate failure state. The bearing capacity of the post-buckling stage can effectively improve the fire-resistance performance of the stainless steel column with constraints.