混杂纤维-钢筋自密实混凝土T梁抗剪性能的试验研究

EXPERIMENTAL RESEARCH ON SHEAR BEHAVIOR OF HYBRID FIBER REINFORCED SELF-CONSOLIDATING CONCRETE T-BEAM

通过进行一系列混杂纤维-钢筋自密实混凝土简支T梁在对称集中荷载作用下的抗剪试验,研究纤维类型及掺量、配箍率等参数对混凝土T梁斜截面受力性能、纵筋应变、箍筋应变和斜裂缝宽度的影响,分析了用混杂纤维部分替代箍筋的可行性,并将T梁与同等条件下矩形梁的极限剪力进行比较。结果表明,混杂纤维的掺入改善了梁的裂缝形态,减小了最大斜裂缝宽度。混杂纤维增加了梁的极限剪力和对应于极限剪力的加载点位移、韧性等。混杂纤维可以限制纵筋应变和箍筋应变的发展。混杂纤维能够部分替代箍筋,增大箍筋间距。混杂纤维能够使T梁从脆性的剪切破坏转变为延性的弯曲破坏。T梁的极限剪力计算时必须考虑翼缘的贡献。

An experimental investigation on the shear behavior of hybrid fiber reinforced self-consolidating concrete T- beam was carried out. The beams were all simply supported and tested under symmetrically placed two-point concentrated loading. The T-beam was designed to study the influence of fiber types, fiber contents and stirrup ratio on the shear behavior, longitudinal steel strain, stirrup strain, diagonal crack width of RC beam. The possibility of partial stirrups replaced by hybrid fibers was analyzed. The ultimate shear load of T-beam was compared with that of corresponding rectangular beam. The experimental results showed that hybrid fibers could improve crack pattern and decreased maximum diagonal crack width. The ultimate shear load and its corresponding load point displacement and toughness of T-beam were increased due to hybrid fibers. Hybrid fibers could limit longitudinal steel strain and stirrup strain propagation. The stirrups could be partially replaced by hybrid fibers. The stirrup spacing was enlarged. The addition of hybrid fibers in adequate content could change the brittle mode of shear collapse into a ductile flexural mechanism. The influence of T-beam flange on the ultimate shear load should be considered.