端部约束箍筋对受弯破坏RC剪力墙变形能力的影响
INFLUENCE OF CONFINING STIRRUPS ON THE DEFORMATION CAPACITY OF RC WALLS WITH FLEXURE FAILURE
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摘要: 该文从机理分析、试验验证以及有限元模拟三个角度分析了端部约束箍筋对钢筋混凝土剪力墙变形能力的影响规律。混凝土应力-应变模型以及平截面假定的理论分析结论表明当原钢筋混凝土剪力墙破坏为混凝土压溃或钢筋屈曲的受弯受压破坏时,端部约束箍筋对其变形能力有积极作用;反之,如果原剪力墙破坏表现为钢筋拉坏的受弯受拉破坏,增加约束箍筋没有明显的影响。以端部箍筋为参数的剪力墙试验和有限元Vector2的分析结果均支持以上结论。提出了增加端部约束箍筋是否能影响无约束剪力墙变形能力的判定公式,公式能准确判断剪力墙破坏类型,从而判定箍筋是否对其变形能力产生影响,判断公式与试验对比结果非常符合。Abstract: The influence of confining stirrups on the deformation capacity of reinforced concrete (RC) walls was studied in respects of theoretical analysis, finite element modeling (FEM) and experimental verification. From the theoretical analysis of concrete stress-strain model and the plane section assumption, adding confining stirrups has positive impacts on the deformation capacity in cases of flexural compression failure in the form of concrete crushing or bar buckling. On the other hand, in situations of flexural tension failure, adding confining stirrups has little influence on the deformation capacity. Results from both experimental studies and the Vector2 FEM validated the above conclusions. A formula was proposed to determine whether adding confining stirrups can improve the deformation capacity of a particular wall section. Predictions from the proposed formula agree very well with test results.