City Research Online

Abstract

In this paper, lightweight concrete with different volcanic scoria coarse aggregate (VSCA) replacement ratios (0 %, 25 %, 50 %, 75 %, 100 %) into steel tube of varying wall thicknesses (2.5 mm, 3 mm, 4 mm), 15 volcanic scoria concrete-filled steel tube (VSCFST) stub column specimens were tested. A systematic study was conducted on the effects of VSCA replacement ratios and steel ratios (6.35 %, 7.69 %, 10.45 %) on their axial compressive capacity. The test results demonstrated that when the VSCA replacement ratio ≤ 50 % and the steel tube wall thickness ≥ 4 mm, the specimens primarily exhibit mid-section buckling failure; when the VSCA replacement ratio ≥ 75 % or the wall thickness ≤ 3 mm, the specimens are prone to end-section shear failure. As the VSCA replacement ratio increases, the ultimate load capacity, elastic stiffness, and ductility of the specimens all show a decreasing trend; however, increasing the wall thickness of steel tube can effectively enhance these mechanical properties. This phenomenon can be attributed to the incorporation of VSCA weakening the synergistic effect between concrete and steel tube. Additionally, the reliability of the finite element model developed in Abaqus software was validated using the test results, followed by a comprehensive parameter analysis. Finally, the applicability of current design codes was verified by comparing experimental data, and a modified ultimate load capacity calculation formula considering the VSCA replacement ratios and steel tube confinement effect was developed. This formula predicts the ultimate load capacity of VSCFST stub columns with a deviation within 5 % from the experimental values.

Publication Type:	Article
Additional Information:	© 2026. This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/by-nc-nd/4.0/
Publisher Keywords:	Volcanic scoria lightweight aggregate, Concrete-filled steel tube (CFST), Axial compressive capacity, Finite element model, Ultimate load capacity calculation
Subjects:	T Technology > TA Engineering (General). Civil engineering (General)
Departments:	School of Science & Technology School of Science & Technology > Department of Engineering
SWORD Depositor:	Symplectic Administrator

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