Experiment on the rectangular tubed RC ultra short columns under axial compression and lateral cyclic load

To study the seismic behavior of RCRC ultra short columns, the tests subjected to combined constant axial compression and cyclic lateral shear force of rectangular tubed RC (RTRC) columns including 4 RCRC and 2 common RC columns for comparison were carried out. The main parameters were axial load ratio (0.3 and 0.5) and width to thickness ratio (111 and 166), and the shear span to depth ratio of all the tested columns was 1.0. The results indicated that the failure mode of common RC short columns was shear failure, therefore the RC columns showed little ductility and energy dissipating capacity. Under lateral shear force, RCRC short columns showed no shear failure due to the effective confinement from the outer tube to the core concrete. The RTRC columns showed higher ductility, elastic-plastic deformation capacity and energy dissipating capacity than the common RC columns. The lateral load strength of RCRC short columns increased with the increment in axial load ratio, while the ductility decreased a little, and the width to thickness ratio affected little on the seismic behavior of RTRC ultra short columns.