钢-混凝土组合梁在负弯矩作用下抗剪性能的试验研究

Experimental study on shear behavior of steel-concrete composite beams under negative moment

通过3根钢-混凝土组合梁在负弯矩作用下的试验,研究了其变形发展及破坏过程,得到了组合梁的跨中剪力-挠度曲线、交界面滑移曲线和沿截面高度分布的应变变化曲线,分析了剪切连接程度、截面尺寸、剪跨比、材料强度、钢筋配置等因素对组合梁承载力和延性的影响。对钢梁进行了塑性分析,得出在负弯矩作用下钢-混凝土组合梁抗剪承载力的提高不是由于钢梁腹板的硬化效应所致,而是由于混凝土翼板的贡献,并提出了考虑混凝土翼板影响的组合梁在负弯矩作用下抗剪承载力计算公式。将计算结果与实测结果进行了比较,二者吻合良好。

In the experiment of 3 steel-concrete composite beams subjected to negative moment,the deformation and failure pattern of the composite beams were observed.The shear force-deflection curve of mid-span,the slip curve of interface between the shape steel and concrete and strain curve at mid-span along the profile height were obtained.Bearing capacity and ductility of composite beams were studied with consideration of the factors of shear connection degree,section size,shear span ratio,material strength and arrangement of steel bar.The plastic analysis of steel shows that the increase in shear strength for steel-concrete composite beams under negative moment is due to the contribution of concrete flange rather than the hardening effect of steel girder webs.The related formula for calculating the shear strength of the composite beam under negative moment is proposed.The predicted values are in good agreements with those of experiment.