Experimental Study On Axial Compression Performance Of Core Steel Reinforced Concrete Columns

Core steel reinforced concrete (CSRC) column is a new type of structuralcomponent with small size shaped steel setting in the core region of a reinforcedconcrete (RC) column, whose axial compression bearing capacity and deformationcapacity being remarkably improved by this technique. The following studies weremainly carried out:(1) Two RC columns and twelve CSRC columns were tested under monotonicaxial loading to investigate the influence of core steel ratio, steel section form,concrete strength, stirrup ratio and infilled concrete strength in steel tube on the axialcompression performance of specimens. The following conclusions were derivedfrom experiment study: The technique of core steel can effectively increase the axialcompression bearing capacity and deformation capacity of RC columns.The axialcompression bearing capacity and deformation capacity of CSRC columns increasewith the increase of steel ratio and the increase rate decreases with the increase ofconcrete strength.The axial compression bearing capacity core circular steel-tubeconcrete columns is higher than that of the core H-shaped steel concrete columns. Theaxial compression bearing capacity of CSRC columns increases with the increase ofinfilled concrete strength in steel tube and the increase rate decreases with theincrease of steel ratio. The core H-shaped steel can develop its yield strength whencore H-shaped steel concrete column reached its maximum bearing capacity, whilethe core steel tube concrete can only develop73~79%of its maximum capacity forthe core circular steel-tube concrete column reaching its maximum bearing capacity.(2) Axial compression resistance mechanism of CSRC columns was studied onthe basis of experimental study. Confining effect of stirrups and steel-tubes to theconcrete was considered and formulas to calculate the ultimate compressive bearingcapacity of CSRC columns were proposed. The calculated results showed goodagreement with the test results. The bearing capacity of core H-shaped steel concretecolumn an be calculated using the superposition method, while the reduction to thestrength of core steel tube concrete must be considered rationally when calculatingthe maximum strength of core steel tube concrete columns.(3) Nonlinear numerical simulatiom of CSRC columns under monotonic loading are developed with ABAQUS. It is indicated that the numerical simulationtechnique used in this paper can rationally simulate the experimental process ofCSRC columns. Parametric studied was conducted on axail compression performanceof CSRC columns.