钢纤维混凝土梁压、弯组合作用下的承载力分析
|
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。
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.
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.
引文
[1]施岚青,等.混凝土结构设计规范学习指导[M].北京:地震出版社,1991,156~160.
[2]季金文,等.关于“偏心受压N-M相关曲线及相关曲面”的探讨[C].第14节全国结构工程学术会议论文集,2005,269~273.
[3]程庆国,等.钢纤维混凝土理论及应用[M].北京:中国铁道出版社,1999,58~64.
[4]P.Nanakorn,H.Horil.A Fracture-Mechanics-Based DesignMethod dor SFRC Tunnel Linings[J].Tunnelling andUnderground Space Technology,1996,11(1):39~42.
[5]沈荣熹,等.新型纤维增强水泥基复合材料[M].北京:中国建材工业出版社,2004,78~82.
[6]陈惠发[美],A.F.萨里普.混凝土和土的本构方程[M].北京:中国建筑工业出版社,2004,252~257.
[7]郭艳华,等.钢纤维混凝土带裂状态下抗弯承载力的计算方法[J].材料科学与工程学报,2007,25.
[8]关宝树.隧道工程设计要点集[M].北京:人民交通出版社,2003.
[2]季金文,等.关于“偏心受压N-M相关曲线及相关曲面”的探讨[C].第14节全国结构工程学术会议论文集,2005,269~273.
[3]程庆国,等.钢纤维混凝土理论及应用[M].北京:中国铁道出版社,1999,58~64.
[4]P.Nanakorn,H.Horil.A Fracture-Mechanics-Based DesignMethod dor SFRC Tunnel Linings[J].Tunnelling andUnderground Space Technology,1996,11(1):39~42.
[5]沈荣熹,等.新型纤维增强水泥基复合材料[M].北京:中国建材工业出版社,2004,78~82.
[6]陈惠发[美],A.F.萨里普.混凝土和土的本构方程[M].北京:中国建筑工业出版社,2004,252~257.
[7]郭艳华,等.钢纤维混凝土带裂状态下抗弯承载力的计算方法[J].材料科学与工程学报,2007,25.
[8]关宝树.隧道工程设计要点集[M].北京:人民交通出版社,2003.
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心