【作者】 李刚；

【导师】 胡大琳；

【作者基本信息】 长安大学 ， 桥梁与隧道工程， 2017， 硕士

【摘要】 钢筋混凝土桥梁在实际使用过程中受二氧化碳、氯离子等外界环境因素侵蚀作用,造成结构损伤及承载力下降等耐久性问题,如何对其承载力衰减的程度进行定量分析是结构耐久性中至关重要的问题。本文依托国家交通运输部应用基础研究项目《混凝土桥梁结构损伤及承载力衰减研究》(2013 319 812 100),对多因素耦合作用下钢筋混凝土梁承载力开展研究,通过人工环境模拟侵蚀试验,分析了腐蚀环境作用下钢筋混凝土梁的抗弯和抗剪承载力衰减规律,并根据试验结果回归分析建立其退化模型,主要完成了以下工作:在人工环境模拟实验室内,对钢筋混凝土试验梁进行二氧化碳、氯离子等多因素耦合作用侵蚀模拟试验,试验结果表明:拉应力对混凝土碳化和氯离子侵蚀均有促进作用、压应力对混凝土碳化和氯离子侵蚀均有抑制作用。对结构性能退化的钢筋混凝土试验梁进行抗弯和抗剪承载力试验,研究其抗弯和抗剪承载力衰减规律;建立钢筋混凝土试验梁的有限元模型进行数值模拟分析,并对其抗弯和抗剪承载力试验结果与理论结果进行对比分析。承载力试验结果显示:随着钢筋锈蚀程度的逐渐增加,其抗弯和抗剪承载力逐渐降低、刚度逐渐减小;相对极限抗弯强度与纵向钢筋截面平均锈蚀率、相对极限抗剪强度与箍筋截面平均锈蚀率均呈现出线性关系,利用试验结果分别回归分析建立钢筋混凝土梁的抗弯和抗剪承载力退化模型。更多还原

【Abstract】 The durability of reinforced concrete bridges has decreased in the process of actual use by the external environment factors such as carbon dioxide,chloride ion erosion.The results of erosion are that the structure is damaged and the bearing capacity drops.So it is a crucial problem on the structure durability how to analyze qualitatively the attenuation of the bearing capacity.This paper is based on the basic research project(2013,319,812,100)of the ministry of communications about the structural damage and the attenuation of bearing capacity of concrete bridges.The bearing capacity of the reinforced concrete beam has been studied under the multi-factor coupling by the artificial environment.The paper analyzes the attenuation law of bending bearing capacity and shear capacity of reinforced concrete beams in the corrosion environment.The degradation models have been established according to the results of the experiment.The mainly work is as follows:The erosion of the reinforced concrete beams is simulated by multiple factors such as carbon dioxide,chloride ion erosion in the artificial environment.The results show that tensile stress has a promoting effect and compressive stress has an inhibitory effect on carbonation and chloride ion corrosion of concrete.This paper analyzes the attenuation law of bending bearing capacity and shear capacity on the performance degradation of reinforced concrete beams.The finite element models on bending bearing capacity and shear capacity of the reinforced concrete beams are established and the results are comprared with the experiment results.The results of the experiment show that the bending bearing capacity and shear capacity decreases and the stiffness decreases gradually with the increase of corrosion and there is a linear relationship between the bearing capacity and the corrosion rate of steel bars.The degradation models of bending bearing capacity and shear capacity have been established according to the results of the experiment.更多还原