剪压区和剪跨比对混凝土板受剪承载力的影响

为探究受拉纵筋屈服的情况下,混凝土板内支座控制截面的相对剪压区高度和板的剪跨比对其受剪承载力的影响,完成了4个混凝土板试件的受剪试验.试件由板、板端伸臂构件、板下柱以及底梁构成,试验借助板端伸臂构件在板端施加力偶,在预估斜裂缝起始位置的外侧施加竖向荷载,在竖向荷载和板端力偶共同作用下使板顶纵筋在斜裂缝与其相交处接近屈服...

Effects of shear compression zone and shear span ratio on shear capacity of concrete slabs

To explore the effects of relative depth of shear compression zone of bearing control section and shear span ratio of slab on the shear capacity of concrete slabs, test of four concrete slab specimens was completed under the condition of yielding of tensile longitudinal bars. The specimen is composed of slab, outriggers at slab end, column under slab, and bottom beam. In the test, force couples were applied at both ends of the slabs with the help of the outrigger members at the ends of the slabs; vertical loads were applied on the outside of the estimated starting position of inclined crack. Under the combined action of the vertical loads and the force couples at the ends of the slabs, the top longitudinal bars of the slabs were close to yield at the intersection of the inclined crack and the bars, and ultimate shear failure of the concrete slabs occurred without the dowel action of longitudinal bars. Test results show that under the ultimate load, the depth of the shear compression zone of the flexural shear control section of concrete slabs had a positive correlation with the ratio of tensile longitudinal reinforcement at the top of the slabs. Pressure and shear force jointly acted on the concrete shear compression zone, and the shear strength of the concrete in this zone was affected by the relative size of the compressive stress. When the compressive stress was large, the shear strength was lower than that under pure shear, and when the compressive stress was small, the shear strength was higher than that under pure shear. Based on the test results, the calculation method for the shear capacity of the inclined section near the bearing was established considering the shear span ratio and the depth of the relative shear compression zone caused by longitudinal tensile reinforcement.