Eccentric compressive test and analytical study of RC medium-length columns retrofitted with welded steel tube and cementitious grout jacket

摘要

The use of welded steel tubes and cementitious grout jackets for strengthening the existing reinforced concrete (RC) columns is an innovative approach, which can substantially enhance the strength of a deficient column without enlarging its cross-sectional area. In this study, an eccentric compressive test of a welded steel tube and cementitious grout jacket retrofitted RC (WSGR-RC) medium-length column was performed to explore the strengthening response of this novel method. A total of 12 eccentrically loaded columns and one axially loaded column were designed to investigate the influence of load eccentricity, area ratio of core concrete, and slenderness ratio on the bearing capacity. Correspondingly, the eccentric compressive performance of the WSGR-RC medium-length columns was analysed in detail using the strength enhancement index, ductility index, filling material contribution ratio, and the M-N curves. The test results revealed that this novel strengthening method could augment the bearing capacity of a deficient RC column. Finally, a simplified calculation method was proposed for predicting the eccentric bearing capacity of the WSGR-RC medium-length column, and the calculated results were found to be in good agreement with the experimental data. This study provides a scientific basis for the application of this novel strengthening method in practical engineering applications.

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