火灾后十字形型钢混凝土柱抗震性能试验研究

Experimental study on seismic behavior of cross-shaped steel concrete reinforced column after fire

为研究分析火灾后十字形型钢混凝土柱的力学性能,以是否受火以及轴压比两个变化因素,设计3根受火和1根未受火的型钢混凝土十字形柱并进行低周反复荷载试验。受火试验后,对十字形柱的滞回曲线、位移延性系数、骨架曲线等力学性能进行分析。试验结果表明:十字形型钢混凝土柱在轴压比不同时表现的破坏形态不同,构件的破坏形态随轴压比的增加发生了由剪弯破坏到弯曲破坏再到剪切破坏的过程;较未受火试件,火灾对十字形型钢混凝土柱的材料力学性能造成损伤,试件耗能能力降低,水平极限承载力明显下降,同时试件的刚度退化也比较严重;在一定范围内提高轴压比,十字形型钢混凝土柱耗能能力增大,其延性系数减小,同时增大轴压比能够有效地提高试件的极限承载力、增大试件的刚度。

In order to study and analyze the mechanical properties of cross-shaped steel reinforced concrete column after fire,3 burned cross-shaped steel concrete reinforced columns and 1 cross-shaped unburned steel reinforced concrete column were designed and tested under low cycle cyclic loading by two factors of fire and axial compression ratio.After fire tests,the hysteretic curves,displacement ductility coefficient and skeleton curves of cross shaped columns were analyzed.The test results show that the failure form of the cruciform steel concrete column is different at the different axial compression ratio.With the increase of the axial compression ratio,the failure mode of the component occurred from shear bending failure to bending failure to shear failure.Compared with unfired test specimens,the fire causes damage to the mechanical properties of the cross shaped columns,reduces the energy consumption of the test specimens,and significantly reduces the horizontal ultimate bearing capacity.At the same time,the stiffness of the test specimens is severely degraded.Increasing the axial compression ratio within a certain range increases,the energy consumption capacity of the cross-shaped steel concrete column is increased,the ductility coefficient is reduced,at the same time,increasing the axial pressure ratio can effectively increase the ultimate bearing capacity and increase the stiffness of the test specimens.