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提出采用高延性混凝土改善梁的抗剪性能和变形能力,设计了8个高延性混凝土梁和3个作为对比试件的混凝土梁,并通过静力试验研究不同剪跨比和配筋率高延性混凝土无腹筋梁的破坏形态和破坏机理。高延性混凝土无腹筋梁的剪切破坏形态有挤压破坏、剪压破坏、弯剪破坏和剪拉破坏。试验结果表明:高延性混凝土梁的剪切破坏均表现出一定的延性,与普通混凝土梁的脆性剪切破坏具有明显不同;高延性混凝土梁的剪切裂缝开展缓慢,说明高延性混凝土良好的拉伸应变硬化和多裂缝开展特性能够有效控制剪切裂缝的发展,防止混凝土压碎剥落,显著提高梁的抗剪性能和耐损伤能力;相比普通混凝土无腹筋梁,高延性混凝土无腹筋梁的受剪承载力和变形能力均有明显提高,表明采用高延性混凝土可以显著改善无腹筋梁的脆性剪切破坏模式;剪跨比和纵筋配筋率对高延性混凝土梁的剪切破坏形态和承载力影响较大,其受剪承载力随剪跨比的增大而降低,随配筋率的增大而有所提高。
The high ductility concrete is adopted to improve the shear resistance and deformation capacity of the beam. Eight high-ductility concrete beams and three concrete beams are designed and compared. Static shear tests are conducted to study the effects of different ratios of shear span ratio and reinforcement ductility Failure mode and failure mechanism of concrete without web reinforcement. The shear failure modes of high-ductility concrete without web reinforcement include crush failure, shear failure, shear failure and shear failure. The experimental results show that the shear failure of high ductility concrete beams shows some ductility, which is obviously different from the brittle shear failure of ordinary concrete beams. The shear cracks of high ductility concrete beams develop slowly, which shows that the ductility of high ductility concrete is good The characteristics of extensional strain hardening and multi-fracture can effectively control the development of shear cracks, prevent the concrete from crushing and spalling, significantly improve the shear resistance and damage resistance of the beam. Compared with normal concrete without web beam and high ductility concrete without web beam, Shear load-bearing capacity and deformation capacity are significantly improved, indicating that the use of high ductility concrete can significantly improve the brittle shear failure mode of non-web reinforcement beam; shear span ratio and longitudinal reinforcement ratio of high ductility of concrete shear failure mode and The bearing capacity has great influence, and the shear capacity decreases with the increase of shear span ratio, but increases with the increase of reinforcement ratio.