钢筋锈蚀对混凝土梁破坏模式影响的试验研究

研究钢筋锈蚀对混凝土梁破坏模式的影响.对4组共21根不同剪跨比、不同锈蚀程度的混凝土梁进行了试验，研究发现，纵向配筋率及剪跨比相同的情况下，随着纵筋、箍筋锈蚀程度的变化，梁会产生弯曲、剪压、剪切-粘结3种不同形态的破坏.针对此现象，基于试验研究结果并结合相关文献的试验结果，根据现行规范中的分析理念建立了考虑剪跨比、箍筋锈蚀率、纵筋锈蚀率及粘结退化等因素影响的锈蚀混凝土梁受剪承载力计算公式.据此再考虑弯剪区的平衡条件，分析讨论得出了试验梁产生破坏形态转变的临界条件和锈蚀混凝土梁构件的综合承载能力的变化规律，从而建立了锈蚀混凝土梁破坏模式转变的分析模型.据此模型分别以纵筋锈蚀率和箍筋锈蚀率为横、纵轴，考虑剪跨比等因素得出临界曲线划分的破坏形态区域与试验结果吻合较好.

Experimental Research on the Failure Mode of Concrete Beam Due to Steel Corrosion

The influences of reinforcement corrosion on reinforced concrete beam failure modes are investigated. Experiments were carried out on 4 groups of the 21 reinforced concrete beams with different shear span ratio and different reinforcement corrosion degree. It is found that reinforced concrete beam specimens with the same longitudinal steel ratio and the same shear span ratio have three kinds of failure mode, i.e. bending failure, shear-compression failure and bond- shear failure along with the different corrosion extent of longitudinal and stirrups steel. Considering this phenomenon, and based on the experimental research and other related test results from literatures, a shear bearing capacity formula of corroded reinforced concrete beam that takes into account the effect of shear span ratio, corrosion ratio of stirrup and that of longitudinal bar, as well as the steel-concrete bond degradation, was established by utilizing the analytical concept of GB 50010-2010 code. Through the analysis and discussion of the critical conditions of failure mode transitions and the variation of general bearing capacity for the test beams, the analysis model of reinforced concrete beam failure transitions is proposed. Taking longitudinal reinforcement corrosion rate as the horizontal axis and stirrup corrosion rate as the longitudinal axis, according to the analysis model and considering the influence of shear span ratio and other factors to get the critical curve, the experimental results fit well with failure mode regions devided by the critical curve. The application of this model can make the preliminary judgment and control the damage form of the beam by different reinforcement corrosion rates.