Axial stability of chloride-corroded CES slender columns: Experimental and numerical study

This paper investigated chloride-corroded concrete-encased steel (CES) slender columns subjected to axial loading. Twelve specimens were tested to evaluate the effects of corrosion on failure modes and mechanical performance. Results show that chloride corrosion accelerates structural degradation and shifts failure from end-region to mid-span as corrosion intensifies. Higher slenderness ratios amplify corrosion-induced losses in load-bearing capacity and stiffness. Based on the test data, a predictive formula was proposed to estimate axial load capacity considering section loss and confinement effects. Stability analysis using a modified Euler approach indicated no instability failure but revealed a reduced safety margin with increasing corrosion severity and slenderness. A validated finite element model was developed, and parametric analysis showed that CES columns experience significant stiffness and stability deterioration when the slenderness ratio exceeds 62. The findings support structural assessment and maintenance planning for CES members in corrosive environments.