THEORY AND TECHNOLOGY OF SPLIT REINFORCED CONCRETE COLUMNS

In reinforced concrete tall building structures, the sections of the frame columns are larger and their shear-span ratios are smaller due to the limitation of the axial-compression ratio of the columns. Some short and even ultra short columns at the bottom floors of the structures are prone to brittle shear failure which may result in damage and even collapse of the structures because of their poor ductility during earthquakes. A technique to split a rectangular short column into 2 or 4 elemental columns with the same section and individual reinforcement is introduced. As a result, the shear-span ratio of the short column is doubled and the short column is changed into “long” columns directly. In this paper, the split reinforced concrete column technique is systematically investigated, which covers the theoretical, experimental and applicable studies of the bearing capacity and seismic behavior of split columns, the seismic behavior of the beam-column joints of the frame with split columns, and the integral seismic behavior and main suggestion for design and construction of the frame with split columns. It is shown that the split column reduces the bearing capacity of the column to bending slightly, keeps the bearing capacity to shearing unchanged, but increases the deformation capacity and ductility of the column remarkably. In addition, the failure pattern of the column is changed from the shearing pattern to the flexural pattern, improving the seismic behavior of the reinforced concrete short columns and the seismic safety of the reinforced concrete tall building structures significantly. The present research work has gained a first-class award of the Tianjin Municipal Science and Technology Achievements, a Chinese patent for invention and a Chinese patent for utility model. It provides reliable theoretical foundation, experimental basis and engineering illustration for the application of the technology of split reinforced concrete column in the aseismic design for reinforced concrete tall building structures.