A numerical simulation method for analyzing the biaxial compression-bending behavior of steel reinforced concrete T-shaped columns: experimental verification and ultimate capacity analysis

In order to investigate the biaxial bending behavior of steel reinforced concrete T-shaped columns, an efficient numerical simulation method using ZeroLength element in OpenSees was presented. Steel reinforced concrete T-shaped columns with bending failure mode were calculated by the proposed method. The simulation results agreed well with the test results. The effects of axial compression ratio, loading angle, concrete strength, steel ratio, steel strength and ratio of limb height and limb thickness on the ultimate flexural capacity of steel reinforced concrete T-shaped columns were analyzed. The results show that the flexural capacity of steel reinforced concrete T-shaped columns can be improved by increasing axial compression ratio, concrete strength, steel thickness, steel strength and ratio of limb height and limb thickness when the axial compression ratio is within the range of limit axial compression ratio. However, if the axial compression ratio is out of the limit, the increase of axial compression ratio and concrete strength lead to the decrease of the flexural capacity of columns. The weak loading direction of T-shaped columns is 90° (the direction along the flange). When the loading angle of columns is 45°, the limit axial compression ratio reaches its maximum value, and the limit axial compression ratio may be reduced by increasing the concrete strength. When the axial compression ratios are in the range of 0~0.4, 0.4~0.9 and 0.9~1.4, respectively, the relation curves of biaxial flexural capacity of steel reinforced concrete T-shaped columns shall be rectangle, oval and diamond, respectively. Moreover, computational formulas of the biaxial flexural capacity of steel reinforced concrete T-shaped columns were derived with different axial compression ratios.