PARAMETER STUDY ON THE COLUMN REINFORCED BY INNER CIRCULAR STEEL TUBE UNDER AXIAL FORCE

Using the method of the nonlinear finite element and numerical integration, the short steel reinforced concrete (SRC) columns reinforced by inner circular steel tubes are analyzed and calculated. With the program, the whole curve of ultimate bearing capacity in axial force is simulated. Effects of the ratios of longitudinal steel bars, different stirrup characteristic values, concrete grades from C40~C70, and ratio of inner steel tubes are discussed. The outlook of applied range of these parameters is also given. Results show that these ranges are reasonable and efficient, which can be used in engineering directly. A simplified formula to estimate the appropriate thickness of inner steel tube is put forward for optimizing the column. Application of this column in two actual engineering indicates the correction of this formula.