Analytical model for predicting axial compressive behavior of steel reinforced concrete column

Steel reinforced concrete column has been widely applied in high-rise buildings and long-span structures. In this paper, an analytical study is carried out for predicting the axial compressive behavior of steel reinforced concrete (SRC) column using cross-shaped steel section with flanges. Firstly, respective material models were established for different components in the composite cross-section, including highly confined concrete, partially confined concrete, unconfined concrete, steel section as well as steel reinforcement. For highly confined concrete, the interaction mechanism between steel section and confined concrete has been investigated, based on which a uniaxial stress-strain relation is established. For partially confined concrete, as the hoop may not yield, an iterative procedure is applied to calculate the real stress in hoops and then the effective lateral confining pressure. For steel section, the biaxial stress state is considered in the material model. Based on section analysis method, a unified analytical model is then proposed and verified through comparison of analytical results with test results on SRC and partially confined SRC (PSRC) short columns. At last, a simplified method for calculating the real stress of the hoop and then the strength of partially confined concrete was proposed to avoid the iterative process and save the computing time.