新型截面型钢混凝土柱抗震性能试验研究

提出配置扩大十字型钢和45°布置十字型钢两种截面形式的新型型钢混凝土柱，通过4个新型与1个普通型钢混凝土柱的低周反复荷载试验，研究新型截面型钢混凝土柱在较高轴压比下的破坏特征、滞回和骨架特性，并分析配钢形式和轴压比对柱抗震性能的影响。试验结果表明：新型截面型钢混凝土柱在压、弯、剪共同作用下均发生了弯曲破坏，在加载后期，即使纵筋外鼓屈服以及型钢翼缘局部屈曲，柱的竖向承载力仍较为稳定；新型截面型钢混凝土柱试件滞回曲线饱满，无捏缩现象，等效黏滞阻尼系数均达到0.45以上，并且截面配钢率相差不大的情况下，其变形和耗能能力明显大于普通型钢混凝土柱；新型截面型钢混凝土柱在高轴力下的承载能力和变形性能良好，其轴压比限值可比规范规定有所提高。

Experimental study on seismic behavior of steel reinforced concrete columns with new-type cross sections

Two new-type cross sections were put forward for steel reinforced concrete columns. One is cross-shaped steel whose flanges are in contact with concrete cover, and the other is rotated cross-shaped steel whose webs coincide with diagonal line of column sections. Failure patterns, hysteretic characteristics and skeleton curves of columns with high axial compression ratio were researched by tests of four new and one common specimen under low cycle reversed loading, meanwhile, effects of steel shape and axial compression ratio on seismic performance of columns was analyzed. The results show that bending failure is occurred for steel reinforced columns with new-type cross sections under the combined action of compression, bending and shear, and vertical bearing capacity of columns could keep better stability although yielding of the longitudinal reinforcement and local buckling of flanges happen. The hysteretic curve of new-type columns is plumper whose equivalent viscous damping coefficients are all over 0.45. Deformation and energy dissipation capacity of new-type columns is much higher than common steel reinforced concrete columns when their steel ratio differs little. At last, the new-type columns have better bearing capacity and deformation capacity under high compressive axial load whose limit value of axial compression ratio could be increased compared with regulations of current seismic code.