Dynamic performance of RAC-filled double-skin tubular columns subjected to cyclic axial compression

Abstract To meet the requirements of sustainable development, recycled aggregate concrete (RAC) was suggested to be used in double-skin tubular columns (DSTCs). These new RAC-filled DSTCs were loaded by a cyclic axial compression to investigate their dynamic performance. An experimental program including 15 RAC-filled DSTCs with different loading schemes and recycled coarse aggregate (RCA) substitution rates was conducted. All RAC-filled DSTCs failed due to the rupture of the basalt fibre-reinforced polymer (BFRP) outer tube. According to the experimental results, it can be concluded that: (1) the RCA substitution rate and loading scheme exhibited an important influence on the mechanical behaviour of the RAC-filled DSTCs and stress–strain relationship of the confined RAC core; (2) the confinement effect enhanced the ultimate load and improved greatly the deformation ability of the RAC-filled DSTCs; (3) the plastic and unloading strains exhibited a very good linear relationship; (4) the dynamic load caused the plastic strain and the strength deterioration of the RAC core. Additionally, existing theoretical models were modified to predict the unloading and reloading curves of RAC-filled double-skin tubular columns and an acceptable accuracy was achieved.