钢筋钢纤维混凝土深梁抗裂度的计算方法

通过对28根深梁的试验研究，探讨了钢纤维混凝土层厚、钢纤维体积率和剪跨比等因素对钢筋钢纤维增强部分混凝土深梁正截面抗裂度和斜截面抗裂度的影响，以及达到全截面加入钢纤维对抗裂度增强效果的钢纤维混凝土层厚。试验表明：深梁的抗裂度随钢纤维体积率的增加而增大，当钢纤维体积率ρf=20%时，正截面可提高80%左右，斜截面抗裂度可提高50%左右，当钢纤维混凝土层厚达到深梁高度的0.6倍时，可 达到全截面加入钢纤维对抗裂度的增强效果。提出了与普通钢筋混凝土深梁和钢筋钢纤维混凝土深梁相衔接的钢筋钢纤维增强部分混凝土深梁正截面抗裂度和斜截面抗裂度的计算公式。

Calculation method for crack resistance of steel fiber concrete deep beams with reinforcement

The effect of concrete layer thickness with steel fibers,volume fractions of steel fibers and shear to span ratio on crack resistance of steel fiber reinforced concrete deep beams with reinforcement is investig ated experimentally through twenty-eight beam tests.The specimens include 3 con ventional concrete deep beams with reinforcement,13 whole section steel fiber concrete deep beams with reinforcement and 12 partial section steel fiber reinforced concrete deep beams with reinforcement.The results show that the steel fibers remarkably elevate the crack resistance.When volume fraction reaches 2.0%,the normal section crack resistance elevates 80% and diagonal section crack r esistance 50% approximatly.The effect of steel fiber concrete with layer thickness of 0.6 beam depth is equivalent to that of full depth.Base on the experimental data a universal formula for calculating the crack resistance of deep beams with different thickness of steel fiber concrete layer is proposed.