【摘要】 钢纤维混凝土开裂后,钢纤维能在开裂面上提供一定的拉应力,这类似钢筋混凝土中受拉钢筋的作用。与钢筋混凝土不同,钢纤维混凝土开裂面上的拉应力随裂缝宽度的增加而逐渐降低。本文通过四点弯曲试验得到钢纤维混凝土梁开裂截面上钢纤维拉应力与裂缝宽度曲线,然后以此为基础对轴力、弯矩组合作用下的钢纤维混凝土梁的承载能力进行分析,得到钢纤维混凝土梁在轴力和裂缝宽度作用下的抗弯承载力计算公式。最后用得到的计算公式做出钢纤维混凝土梁在极限承载状态下的N-M相关曲线。计算分析表明,钢纤维混凝土梁开裂后,开裂面上的应力重分布会使截面的抗弯力臂增大,从而提高截面的抗弯承载力。并且开裂截面的抗弯能力也随轴压力的增大而有明显提高。这就从理论上解释了受压钢纤维梁开裂后的抗弯承载力不但没有降低,反而有所提高的现象。更多还原

【Abstract】 After appearance of cracks of steel fiber reinforced concrete,steel fiber can provide certain tension stress on the crack plane analogous to the function of tension reinforcement in reinforcement concrete.However,differing from reinforcement concrete,the tension stress on the crack plane of steel fiber reinforced concrete is decreasing with the increasing of crack width.This paper obtains the relationship curve about tension stress of steel fiber and crack width on the crack section of steel fiber reinforced concrete from four points bending experiment.Further more,that relationship curve is used to analyze the capacity of steel fiber reinforced concrete under combination action of axle pressure and bending moment from which the equation of bending moment capacity is obtained.At last that equation is used to get N-M interaction curves under extreme capacity condition.The experimental and analytical results indicate that when crack are created,stress redistribution on crack plane can increase the force arm of bending,which increase bending capacity.The bending capacity of crack section also increases with the increasing of axle pressure.Therefore,it theoretically explains the phenomenon that bending capacity does not decrease but increase.更多还原