【摘要】 为研究腹板斜裂缝对混凝土梁剪切变形的影响程度,特开展了根小剪跨比变截面混凝土约束梁的剪切变形试验研究。设计制作了用于梁段应变测量的组合式测量框格,提出了变截面梁弯曲、剪切变形分离测量计算方法,实现了基于框格应变测量值的斜裂缝开展前、后的弯曲与剪切变形分离。试验研究表明,在斜裂缝开裂前,剪跨比是影响剪切变形比例的主要因素;斜裂缝开裂后,配箍率对剪切变形的影响更为明显;第一条主斜裂缝出现和箍筋屈服是荷载-剪切变形曲线的两个转折点;提高混凝土强度等级和配箍率能增加开裂后抗剪刚度,抑制开裂后剪切变形的发展。更多还原

【Abstract】 To study the impact of diagonal cracks on shear deformation of reinforced concrete(RC) beams, restrained RC beams with variable depth were tested under loading conditions of small shear span to depth ratio for their shear deformations. A self-tailored strain measuring grids was designed and installed on the sides of the beam specimens for strain measurement. An approach for deformation calculation based on the strain gauge, which is able to distinguish the flexural and shear portions before and after the propagation of diagonal cracks, was proposed. The test results show that the shear span to depth ratio has substantial influence on the shear deformation ratio before shear cracking, while the stirrup ratio has a more significant impact on shear deformation after the shear cracking. The turning points of load-shear deformation curve correspond to the occurrence of the first major diagonal crack and the yielding of stirrup. Increasing the strength of concrete and the stirrup ratio can improve the post-cracking shear stiffness, and restrain the development of shear deformation after shear cracking.更多还原