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通过9根钢筋混凝土梁的低周往复试验,对比研究不同抗震等级RC梁的破坏形态、延性、滞回性能、耗能能力及刚度退化等。结果表明:剪跨比为2.0的试件发生弯曲滑移破坏,剪跨比为3.0的试件和剪跨比为4.2的试件发生弯曲破坏;剪跨比为2.0的试件抗震等级分别为二级和四级,表明满足规范抗震等级要求的RC梁试件无法避免发生弯曲滑移破坏;同组试件中,抗震等级越高(配箍率越大),试件的极限位移角越大。除去发生弯曲滑移破坏的试件,试件的极限位移角随抗震等级的提高呈线性增长趋势;抗震等级相同时,弯曲滑移破坏的试件刚度退化比弯曲和弯剪破坏试件严重;弯曲滑移破坏与弯曲破坏的RC梁试件其耗能分别集中在塑性阶段的前期和中后期。
Through the low-frequency reciprocating tests of nine RC beams, the failure modes, ductility, hysteretic behavior, energy dissipation capacity and stiffness degradation of RC beams with different seismic ratings are compared. The results show that the specimen with shear-span ratio of 2.0 has bending-slip failure, the specimen with shear-span ratio of 3.0 and the specimen with shear-span ratio of 4.2 have bending failure, and the specimens with shear-span ratio of 2.0 have Grade two and Grade four indicate that bending and sliding failure can not be avoided in RC beam specimens meeting the requirements of the standard seismic grade. In the same group of specimens, the higher the seismic rating (the greater the stirrup ratio), the more the ultimate displacement angle of the specimen Big. When the specimen with bending slip damage is removed, the ultimate displacement angle of the specimen increases linearly with the increase of the anti-seismic grade. When the seismic rating is the same, the stiffness degradation of specimens with bending slip damage is worse than that with bending and bending failure. The energy dissipation of RC beam specimens with bending damage and bending failure are mainly concentrated in the early and middle stages of plasticity.