为了研究RC框架变梁变柱中节点的抗裂性能,进行了6个变梁变柱中节点试件在低周反复荷载作用下的拟静力试验,分析了节点核心区尺寸、轴压比等因素对异型中节点抗裂性能的影响。研究结果表明:异型节点初裂时斜裂缝主要出现在由小梁和上柱构成的小核心区,小核心区开裂荷载为极限荷载的50%~60%;抗裂性能较常规节点劣化,初裂阶段的剪力基本由小核心区混凝土承担,增大轴压比可以提高异型中节点的抗裂承载能力。提出的变梁变柱中节点抗裂承载力计算公式,可供结构工程设计时参考。
Six specimens of abnormal interior joints were tested under reversed cyclic loading. Experiments were carried out to investigate the influence of joint core dimensions and axial compression ratio on crack resistance of abnormal joints. The results show that: cracks mainly appear in the minor core (determined by the small beam and the top column) ; the crack resistance loads are from 50% to 60% of the ultimate load of abnormal interior joints, and the crack resistance is worse than that of ordinary joints; the crack resistance capacity is chiefly provided by the minor core concrete, and axial compression ratio is a significant parameter to increase the crack resistance capacity. A theoretical formula of crack resistance capacity was proposed, and it can be served as reference for engineering practice. 5 tabs, 2 figs, 9 refs.