STUDY OF NORMAL SECTION BEARING CAPACITY OF STEEL REINFORCED CONCRETE COLUMNS WITH CROSS-SHAPED STEEL ALONG DIAGONAL LINE

For the purpose of improving seismic performance of steel reinforced concrete ( SRC) columns with high axial compression ratio，SRC columns with cross-shaped steel along diagonal line were put forward，whose bearing capacity calculation could not adopt the related formulas of current codes directly． The strength superposition method and limit equilibrium method were employed to calculate normal section bearing capacity of proposed SRC columns on this background． The bearing capacity of confined concrete，steel flange and steel web were calculated respectively first，and then the maximum axial force and ultimate moment were obtained according to superposition principle of the strength superposition method． From the thought of material mechanics，the simplified calculation formulas of normal section bearing capacity were deduced through regressing numerical simulation results of a large number of SRC columns with cross-shaped steel subjected to biaxial eccentric compression of limit equilibrium method． Three experimental specimens and sixteen finite element simulated columns with the same sections were calculated using the above formulas and the theoretical results agreed well with practical bearing capacity of the columns，which verified the correctness and applicability of the proposed formulas．