Flexural performance of reinforced self-compacting concrete filled steel tube (Rsccfst) beams

Reinforced concrete filled steel tubular (RCFST) structures offer several structure benefits and has been increasingly used in civil engineering structures. In this study a total of 16 beam specimens were tested to investigate the flexural behavior of RCFT experimentally, 14 of them filled with reinforced self-compacting concrete, two filled with self-compacting concrete and two were hollow beams. The main parameters varied in this study were: (1) ratio of longitudinal reinforcement area to the concrete area 3%, 5% and 7%; (2) distribution of axial reinforcement (two layers and three layers); (3) spacing between stirrups (6cm and 12cm). It concluded that the internal reinforcement with different ratios has obvious effect on bending capacity and failure mode of beam specimens and insignificant effect on their ductility. The moment versus mid-span deflection curves and moment versus ultimate strains curves for specimens presented. Comparisons made with the predicted specimens capacity results using the existing methods, such as AISC 360-10 and Eurocode 4 and generally good agreement between predicted and experimental results achieved.