带缺陷钢筋混凝土叠合梁斜截面抗剪性能试验研究

Experimental study on shear resistance of oblique section of reinforced concrete composite beams with defects

为了研究叠合面的缺陷对叠合梁构件斜截面抗剪能力的削弱程度,通过在叠合梁弯剪段叠合面上放置不同长度的泡沫板,模拟了在生产制造、装配施工阶段出现的质量缺陷。试验研究了带缺陷的钢筋混凝土叠合梁的抗裂性能、抗剪承载力、破坏特征以及在这个过程中箍筋的作用。结果表明:与无缺陷试件相比,2根带缺陷试件的开裂剪力分别降低了6.3%和37.5%,极限抗剪承载力分别降低了25.6%和39.5%;在斜裂缝出现前,3根试件的刚度和竖向裂缝发展均与一般整浇梁类似;在斜裂缝出现后,叠合面缺陷尺寸越大的试件,箍筋越早受力并率先发生屈服,试件刚度显著下降;叠合面存在缺陷的试件弯剪段最终破坏裂缝均呈现出相似的形状特征,且与无缺陷试件有较大差异。

In order to study the erosion degree of shear resistance of composite beam members due to the defects of composite interface, the quality defects at the stage of production and assembly construction were simulated by placing different lengths of foam plates on the composite interface of the bending and shear section of composite beam. The crack resistance, shear bearing capacity, failure characteristics and the role of stirrups in the process of reinforced concrete composite beams with defects were studied experimentally. The results show that compared with the non-defective specimen, the cracking shear force of two specimens with defects decreases by 6.3% and 37.5% respectively, and the ultimate shear capacity decreases by 25.6% and 39.5% respectively. Before the oblique crack appears, the stiffness and the development of vertical cracks of three specimens are similar to that of the general cast-in-place beams. After the oblique crack appears, the larger the defect size of the composite interface is, the earlier the stirrups are stressed and yield first, and the stiffness of the specimen decreases more significantly. The final failure cracks in the bending shear section of the composite beams with defects in the composite interface show similar shape characteristics and are quite different from those of the non-defective specimens.