Strength and residual stress evaluation of stub columns fabricated from 800 MPa high-strength steel

• 800 MPa steel specimens exhibit sufficient strength under uniform compression.
• All P-M test results exhibit the AISC norminal P-M interaction strength.
• Experimental P-M strength is accurately predicted with strain compatibility method.
• The measured residual stress is independent of the yield stress of the base metal.

In this study, stub columns subjected to concentric and eccentric loads were tested to check the applicability of the current local stability criteria to 800 MPa high-strength steel (HSA800) recently developed in Korea. The key test variables in the concentrically loaded tests included the plate-edge restraints and the width-to-thickness ratio. Specimens made of ordinary steel (SM490) were also tested for comparison purposes. Eccentrically loaded stub column tests were conducted for a range of the P–M combinations by controlling the loading eccentricity. All the concentrically loaded specimens with non-compact and slender sections developed sufficient strengths according to the current local stability criteria. All the eccentrically loaded specimens with non-compact H-sections also exhibited a sufficient P–M interaction strength even higher than that of compact H-section counterparts. The experimental P–M interaction strength was very accurately predicted with the strain compatibility method by using the measured stress–strain curve, or by explicitly considering early strain-hardening property of high strength steel. Residual stresses were also measured by using the non-destructive indentation method to see their dependency or independency on the yield stress of steel material. The measured results of this study again indicated that the magnitude of residual stresses bears no strong relation to the yield stress of steel material, implying that the impact of residual stress on inelastic local buckling of high strength steels is less.