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Active Control over Failure of RC Members by Application of Interrelation between Artificial Pre-Crack and Non-Orthogonal Crack

应用人工预裂与非正交裂纹相互关系主动控制钢筋混凝土构件失效

基本信息

批准号：
13355019
负责人：
MAEKAWA Koichi
金额：
$ 29.04万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

项目摘要

1) In order to clarify the interrelation between artificial pre-crack induced in concrete member and shear crack caused by shear force, a series of experiments was performed. Under both monotonic and cyclic loading, the artificial pre-creak prevented propagation of new share crack and then the capacity and ductility of RC member increased. On the contrary, when the angle between pre-crack and new crack because less than 30 degree, the capacity of member was decreased owing to the new crack formed along the pre-crack.2) Non-orthogonal smeared crack model of enhancing active crack method was adopted as a constitutive law to deal with non-orthogonal cracks with intersection. Comparinson with the experimental results verified that the proposed model could well predict the behavior of cracks with mutual interaction.3) Shear behavior of concrete members with embedded plastic plates, as devices to emulate pre-cracks, was studied based on both experimental facts and analytical approach. As a result, proposed joint element had a beneficial effect on modeling consecutive plates.4) The accuracy of the proposed non-orthogonal crack model was verified with experiments of RC plate structures under multi-directional loading. The result showed that active-crack method, which defined Intersection angle of 22.5 degrees as a threshold, could well predict interrelation between non-orthogonal cracks. In addition, the application of the model for structures that consist of high strength concrete and high strength reinforcing bars was proven.5) Because thermal stress was assumed as an introduction source of pre-cracks, the tension-stiffness behavior of embedded steel in concrete under high temperature was clarified experimentally. The manifested characteristics were incorporated into the structural numerical analysis system.

1)为了阐明混凝土构件中人工预裂缝与剪力引起的剪切裂缝之间的相互关系，进行了一系列试验。在单调荷载和循环荷载作用下，人工预裂缝均能有效地阻止新裂缝的扩展，提高构件的承载力和延性。当预裂缝与新裂缝夹角小于30 °时，新裂缝会沿预裂缝沿着形成，从而降低构件的承载力。2）采用增强活性裂缝法中的非正交弥散裂缝模型作为本构关系，处理交叉非正交裂缝。通过与试验结果的对比，验证了该模型能够较好地预测裂缝相互作用的行为。3）基于试验事实和分析方法，研究了预埋塑性板混凝土构件的抗剪性能。结果表明，所提出的节点单元对连续板的模拟具有良好的效果。4）通过钢筋混凝土板结构在多向荷载作用下的试验，验证了所提出的非正交裂纹模型的准确性。结果表明，以22.5度交叉角为阈值的活性裂纹法可以很好地预测非正交裂纹之间的相互关系。此外，还验证了该模型在高强混凝土和高强钢筋组成的结构中的应用。5）由于假定温度应力为预裂缝的引入源，通过试验阐明了高温下混凝土中预埋钢筋的抗拉刚度特性。所表现出的特征被纳入结构数值分析系统。