Ultimate bearing capacity of composition columns reinforced with the prefabricated SHSCUS filled with steel tubes subjected to axial load

This paper presents an experimental investigation on the short composition columns reinforced with the prefabricated super high strength concrete used stone-chop(abbreviated to SHSCUS) filled with steel tubes with I RC as reference. The experimental parameters were the concrete type inner steel tubes, and LID ratio, steel ratio and so on. The performance of the composition columns was investigated using different diameter-to-thickness ratio of steel tubes ranging from 15 to 26.6, and different cubic strength of 126.7, 120.3, 122.4, 134.4, 125.4, 111.4, 108.6MPa of infill concrete. The experimental results showed that concrete cover falling off was prior to specimens failure, and that the design rule, as specified in current code suitable for HSC overestimate the ultimate bearing capacity, were not suitable for the case with SHSCUS. Then the hypothesis was put forward based on experimental phenomena observed, and the formula of its ultimate load capacity was suggested based on superposition method, by which the predicted values have a good coincidence with those from the experiments.