纤维替代箍筋自密实混凝土T型梁抗剪性能试验研究

EXPERIMENTAL RESEARCH ON SHEAR PROPERTIES OF SELF-COMPACTING CONCRETE T-BEAMS WITH FIBERS INSTEAD OF STIRRUPS

通过对8根混杂纤维与不同箍筋的钢筋自密实混凝土简支T型梁在对称集中荷载作用下的抗剪试验,分析不同纤维类型和掺量、箍筋直径、间距及强度等参数对混凝土T型梁极限抗剪承载力、剪力-位移曲线、纵筋应变和破坏形态的影响。研究表明:掺入纤维可显著提高混凝土T型梁的极限剪力,限制纵筋应变发展,延缓裂缝出现和发展;在相同剪跨比的情况下,将T型梁从脆性的剪切破坏转变为延性的弯曲破坏;钢纤维或混杂纤维能够部分替代箍筋,纤维与箍筋共同作用时,可减小原设计梁中箍筋的配箍率或降低箍筋的强度。

An experimental study on shear performances of fiber-reinforced self-compacting concrete T-beam was carried out. Eight simple-supported T-beams subjected to two concentrated loading placed symmetrically were tested,to study the influences of fiber types,fiber contents and diameters,spacings and strength of stirrups on ultimate shear capacity,shear-force-displacement curves,longitudinal rebar strain and failure modes. The experimental results showed that the ultimate shear capacity of T-beams increased due steel fibers of being mixed or hybrid fibers. Fibers could restricted strain propagation of longitudinal rebars,delay appearance and development of cracks and change failure modes from brittle shear collapse into ductile flexural failure. The stirrups could be partially replaced by steel fibers or hybrid fibers. The design requirements for contents or strength of stirrups for beams could were reduced in combination with fibers and stirrups.