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Study on the deterioration of structural performance of RC members due to rebar corrosion

钢筋锈蚀导致RC构件结构性能恶化的研究

基本信息

批准号：
06402045
负责人：
TOMOSAWA Fuminori
金额：
$ 10.3万
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：
1994
资助国家：
日本
起止时间：
1994 至 1996
项目状态：
已结题

项目摘要

The study was made on the quantitative evaluation of the relationship between the level of rebar corrosion and the structural performance of RC members, and on the application of carbon fiber sheet to strengthening of RC members deteriorated due to rebar corrosion. The following results were obtained.1. Finite element analysis showed that the direction of cracking differed according to the forms of corrosion and the localized corrosion needed more amount of rust to create cracking of cover concrete.2. The mechanical properties of rebar subjected to pitting corrosion and uniform corrosion were expressed as a function of the weight loss percentages of rebar and introduced into the constitutive law of rebar in FEM analysis.3. Pull-out tests were conducted on rebars corroded to different extent, and the bond strength and the bond stiffness were expressed as a function of the weight loss percentages of rebar.4. Using the constitutive law of corroded rebar element and that of bond element, finite element analyzes were made on RC beams with corroded rebars. Comparing the results of the analyzes to the experimental results, the validity of the constitutive laws were examined.5. Carbon fiber sheet was effective for the strengthening of both bending strength and shear strength of RC beams with corroded rebars. As the peeling of the sheet determines the strength of beams, sufficient bond area make both the strength and the performance of deformation of beams increase.6. Confining effect disappeared in column above 30% of weight loss of hoop and the strength of column decreased, resulting from the bond failure due to the cracking of cover concrete, the spalling of cover concreate, the decrease of the confining effect due to the breaking of hoop and the decrease of the strength of rebar.

对钢筋锈蚀程度与钢筋混凝土构件结构性能的关系进行了定量评价，并对碳纤维布在钢筋锈蚀劣化钢筋混凝土构件加固中的应用进行了研究。取得了以下研究成果：1.有限元分析表明，不同的锈蚀形式产生的开裂方向不同，局部锈蚀需要较多的锈蚀量才能使保护层混凝土开裂。将受点蚀和均匀腐蚀的钢筋力学性能表示为钢筋失重率的函数，并将其引入有限元分析中的钢筋本构关系。对不同锈蚀程度的钢筋进行了拉拔试验，将粘结强度和粘结刚度表示为钢筋失重率的函数。利用锈蚀钢筋单元本构关系和粘结单元本构关系，对钢筋锈蚀钢筋混凝土梁进行了有限元分析。将分析结果与实验结果进行对比，验证了本构关系的正确性。碳纤维布对锈蚀钢筋混凝土梁的抗弯强度和抗剪强度均有较好的加固效果。由于板材的剥离决定了梁的强度，足够的粘结面积使得梁的强度和变形性能都有所提高。在配箍失重30%以上，由于保护层混凝土开裂引起的粘结破坏、保护层混凝土的剥落、断箍引起的约束作用的减弱以及钢筋强度的降低，柱的约束作用消失，柱的强度降低。