Abstract
The inelastic cyclic behaviour of circular steel tubes infilled with concrete incorporating recycled rubber particles is investigated in this study. Rubberised concrete-filled circular steel tubes are experimentally assessed under lateral cyclic deformations with and without co-existing axial loading. Relatively high levels of replacement of mineral aggregates with recycled rubber aggregates are considered within the test specimens. Typical experimental results are discussed with respect to the member stiffness, capacity, ductility, energy dissipation and failure mechanisms. Although high rubber ratios lead to a considerable loss in concrete strength, the test results show that the corresponding reduction in member capacity is much less significant due to the contribution of the steel tube and the comparatively high confinement effects mobilised within the rubberised concrete. In comparison with members incorporating normal concrete with no rubber particles, the rubberised concrete members are found to exhibit notable increase in ductility and energy dissipation, depending on the rubber content adopted. The test results demonstrate the favourable inelastic cyclic performance of circular steel tubes infilled with rubberised concrete. The findings also provide information and detailed test data for use in numerical and analytical evaluations, including the prediction of stiffness and strength under combined axial and lateral loading as well as ductility and energy dissipation measures, with a view to developing practical assessment and design methods.