Study On Analysis Methods Of Circular Steel Tube Column Filled With Steel-reinforced Concrete

With the development of high-rise and long-span buildings, columns have to bear higher and higher axial load. And because the design of the columns is the keypoint to prevent the collapse of buildings in strong earthquakes, so the columns are required to have high strength as well as high ductility. Based on the summary about the present research on steel reinforced concrete columns,concrete-filled steel tubular columns and steel eccased concrete columns, a new type of composite column-steel tubular column filled with steel-reinforced concrete is studied in this paper. In this type of composite columns, steel section is inserted into concrete-filled steel tubular column. Through the interaction among steel tubular,steel section and concrete, the column will have higher bearing capacity,higher ductility and fire-resistant performance.Because the formulae used for predicting the ultimate bearing capacity of the new type column could base on concrete-filled steel tubular columns, this paper starts with the comparation among eight codes. At first, Design methods and parameters of concrete-filled steel columns in different codes are introduced respectively in this paper. And the calculating results of these codes methods are compared with collected test data. Then, founded on reasonable constitutive relationship of material, obtains the load-displacement curves of short composite column subjected to axial compressive load by finite elements software-ANSYS. The working mechanics of the composite column are also discussed based on the finite elements analyzed results. Then, based on the frontal analysis among many codes, adopt the code of JCJ01-89 and CECS28:90's theory to constitute the bearing capacity formula of the new type composite column. And adopt the Twin Shear Unified Strength Theory to take into account the triaxial compression of concrete. And by mathematics method, the formula of predicting the ultimate bearing capacity of slender composite column is deduced. Finally, through the load-displacement curves, deduce the compressive stiffness of the new type composite column.