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为了研究反复荷载作用下型钢混凝土(SRC)异形柱空间角节点的破坏机理及其损伤演变过程,设计9个试件进行低周反复荷载试验,考虑了柱截面配钢形式、轴压比、加载角度和梁的形式4个变化参数。观察其裂缝发展形态,揭示其破坏机理,获取了荷载-应变滞回曲线、节点核心区剪切变形和梁截面平均曲率。基于能量守恒定律,分析了反复荷载下试件的损伤规律,并分析了各变化参数对其累积损伤的影响。研究结果表明:反复荷载作用下SRC异形柱空间角节点发生的是弯曲、剪切斜压破坏为主、扭转伴随粘结破坏为辅的破坏形态。破坏时节点核心区钢材大部分已屈服,并且型钢应变、核心区剪切角、梁截面平均曲率均随柱肢角度的增加而减小。破坏时试件的累积损伤指标介于0.69~0.84,槽钢桁架试件各级位移下的累积损伤最大;45°加载实腹配钢试件较30°加载实腹配钢试件损伤更加严重;与45°加载试件相比,0°加载试件各级位移下累积损伤程度最高增加30%;轴压比对试件的损伤影响不大;与带钢梁试件相比,带型钢混凝土梁试件累积损伤有较大程度的缓解。
In order to study the failure mechanism and damage evolution process of SRC special-shaped columns under cyclic loading, nine specimens were designed for low-cycle cyclic loading tests. The column sections were equipped with steel forms, axial compression ratio, Angle and beam parameters in the form of four changes. The fracture development pattern was observed, the failure mechanism was revealed, and the load-strain hysteresis curve, the shear deformation of the core region and the average curvature of the beam section were obtained. Based on the law of conservation of energy, the damage regularity of the specimen under repeated load was analyzed, and the influence of various parameters on the cumulative damage was analyzed. The results show that under the action of repeated load, the corner nodes of SRC special-shaped columns are mainly bent and shear baroclinic fractures, and the torsional deformations are complemented by the bond failure. At the time of failure, most of the steel in the core region of the node has already surrendered, and the strain of the steel section, the shear angle of the core region and the average curvature of the beam section decrease with the increase of the angle of the column and limb. The cumulative damage index of the specimens under failure ranged from 0.69 to 0.84, and the cumulative damage was the highest under the displacement of truss specimens at 45 °. ; Compared with 45 ° load specimen, the cumulative damage degree increased by 30% under the displacement of 0 ° loading specimen at all levels; the axial compression ratio had little effect on the specimen damage; compared with the steel beam specimens, Concrete beam specimen cumulative damage to a greater extent, ease.