腹板开洞钢-混凝土组合梁抗剪承载力试验研究

EXPERIMENTAL STUDY ON SHEAR STRENGTH OF STEEL-CONCRETE COMPOSITE BEAMS WITH WEB OPENING

为研究腹板开洞组合梁在静载作用下的竖向抗剪性能,共进行了5根腹板开洞组合梁和1根对比组合梁在集中荷载作用下的实验。试件均为完全剪力连接,主要变化参数为混凝土板厚和配筋率。加载方式为单调静力加载,实验测量内容为竖向荷载、挠度、滑移、截面应变等。试验结果表明:腹板开洞显著地降低了组合梁的刚度和承载力,洞口区域截面纵向应变不再满足平截面假定。增加混凝土板厚能有效地提高组合梁的承载力,增加混凝土板的配筋率能有效地提高组合梁的变形能力。洞口上方混凝土翼板承担了大部分剪力,混凝土翼板对腹板开洞组合梁的竖向抗剪承载力有较大的贡献。研究为腹板开洞组合梁的应用提供了实验依据。

In order to investigate the vertical shear bearing capacity of a composite beam with a web opening, five composite beams with web openings and a contrasting composite beam under a concentrated load were tested.The six beams were all full-interraction, and the major parameters included thickness and reinforcement ratio of a concrete slab. Directional monotonic loads were applied and test measurement included a vertical load, deflection, slip and strain of cross-sections of a composite beam, etc. The test results show that the stiffness and ultimate capacity decreases notably with the area reduction of the composite beam web. According to the longitudinal strain distribution along section height at the hole region, the plane hypothesis is not satisfied any more. The ultimate load carrying capacity and deformability of a composite beam with a web opening can be effectively enhanced by increasing the thickness and reinforcement ratio of a concrete slab. The concrete slab at the top of the hole bears most of the total shear force of a cross-section, which makes a greater contribution to the shear bearing capacity. This study provides an experimental basis for the application of composite beams with web openings.