Compressive strength prediction of circular concrete-filled aluminium tube (CFAT) and aluminium tube-confined concrete (ATCC) stub columns

The aluminium tube-concrete composite columns with concrete infill (including concrete-filled aluminium tube (CFAT) and aluminium tube-confined concrete (ATCC) columns) exhibit significant potential for enhancing structural durability under harsh environmental conditions owing to the excellent corrosion resistance of aluminium alloys. To promote the application of these structures, accurate prediction of their compressive strength is essential. In this study, dedicated databases for the compressive strength of circular CFAT and ATCC stub columns were compiled from existing literature. The CFAT database contains 274 data points, while the ATCC database contains 192 data points. Subsequently, the existing formulas for the compressive strength of the two column types, which are typically based on limited parameter ranges, were reviewed. For CFAT stub columns, a theoretical prediction formula was developed based on the limit equilibrium theory, incorporating a new formula for concrete under triaxial compression; additionally, a regression-based formula was proposed. For ATCC stub columns, a regression-based formula was also proposed. By using the databases with broader parameter coverage, both the existing and newly proposed formulas were evaluated. The proposed theoretical formula demonstrated better accuracy than the existing theoretical ones. Moreover, the proposed regression-based formula for CFAT stub columns achieved the highest prediction accuracy within the database, with a mean prediction error of only 0.4% and a coefficient of variation (COV) of 7.3%. The proposed formula for ATCC stub columns also showed excellent accuracy, with a mean prediction error of -0.1% and a COV of 3.9%. These findings offer valuable guidance for the design and application of CFAT and ATCC stub columns.