混合钢纤维混凝土深梁抗剪承载力分析

为探究混合钢纤维混凝土(HSFRC)深梁的受剪机理，综合考虑混凝土、钢纤维、分布网筋及纵筋对HSFRC深梁抗剪承载力的贡献，将钢纤维并入到深梁的抗拉体系中，建立了基于软化拉压杆模型的抗剪承载力计算方法。然后对4根HSFRC深梁试件进行抗剪性能试验，验证计算方法的合理性，并分析混合钢纤维体积掺量和分布钢筋配筋率对试件抗剪性能的影响。结果表明：计算方法的建立过程合理，可以较准确地预测试件的抗剪承载力；钢纤维掺量的增加会延缓HSFRC应变的发展并提高其最大应变值；分布钢筋对HSFRC应变的影响较小，但其掺量的增加会延缓钢筋应变的发展；钢纤维掺量的增加会提高试件的承载能力、变形能力和初始刚度；分布钢筋配筋率的增加可以提高试件的承载能力并延缓其刚度退化，但试件的变形能力呈现先增大后降低的趋势。

Analysis of shear bearing capacity of hybrid steel fiber reinforced concrete deep beams

To investigate the shear mechanism of hybrid steel fiber reinforced concrete (HSFRC) deep beams, the effects of concrete, steel fiber, web reinforcement, and longitudinal reinforcement on the shear bearing capacity of HSFRC deep beams were taken into consideration, and steel fibers were incorporated into the tensile system of HSFRC deep beams. The calculation method for the shear bearing capacity of HSFRC deep beams was developed based on the softened strut and tie model (SSTM). Then, shear tests on four HSFRC deep beam specimens were conducted to evaluate the proposed method and further investigate the effects of steel fiber volume and web reinforcement ratio on the shear behavior of HSFRC deep beams. Results show that the designed procedure of the proposed calculation method was reasonable, which could accurately predict the shear bearing capacity of the specimens. The increase in the steel fiber volume could decrease the growth rate of the strain of HSFRC and increase the maximum strain of HSFRC. The web reinforcement ratio had little effect on the strain of HSFRC, but the increase in its volume could inhibit the development of the strain of reinforcement. The increase in the steel fiber volume could improve the bearing capacity, deformation capacity, and initial stiffness of the specimens. With the increase in the web reinforcement ratio, the shear capacity increased and the stiffness degradation was delayed, but the deformation capacity of the specimens first increased and then decreased.