【作者】 杨明；

【导师】 曹双寅；

【作者基本信息】 东南大学 ， 结构工程， 2006， 硕士

【摘要】 在锈蚀钢筋混凝土梁中,钢筋的锈蚀引起钢筋的截面面积减少和力学性能的变化、混凝土保护层的开裂以及钢筋与混凝土间粘结性能的变化,这些因素均影响着锈蚀钢筋混凝土梁的受弯性能。本文借助于ANSYS有限元程序,对锈蚀钢筋混凝土梁的受弯性能进行了研究,主要工作和成果有:采用有限元程序模拟钢筋的拉伸试验。研究了锈坑对锈蚀钢筋受拉时应力分布的影响,分析了锈蚀钢筋名义屈服强度和钢筋最大截面锈蚀率的关系,讨论了锈坑深度、宽度、倾斜率对钢筋名义屈服强度的影响。运用非线性弹簧单元刚度的变化模拟钢筋和混凝土之间粘结性能的退化。收集了13根锈蚀钢筋混凝土梁的试验数据,建立了相应的有限元模型并进行分析。通过有限元计算结果和试验结果的对比,验证了本文所建有限元模型的可靠性。在此基础上,讨论了不同锈蚀率下均匀锈蚀钢筋混凝土梁和局部区段锈蚀钢筋混凝土梁的受弯性能,较系统地分析了锈蚀钢筋混凝土梁的承载力、刚度、钢筋和混凝土之间的相对滑移、纵筋应力以及裂缝特征和破坏机理。对各种锈蚀钢筋混凝土梁抗弯承载力计算方法进行比较。从两种极端情况入手,分别考虑锈蚀钢筋与混凝土间完全有粘结和完全无粘结两种状况,对收集的6根锈蚀钢筋混凝土梁和2根未锈蚀梁进行有限元模拟分析,提出了适用于工程实际的抗弯承载力计算模型,并对现有规范中受弯构件刚度的计算公式进行修正,建立了锈蚀钢筋混凝土梁抗弯刚度的计算公式。更多还原

【Abstract】 Corrosion of steel bar in reinforced concrete beams leads to reduction of the cross-section of the steel bar and change of steel mechanical properties, longitudinal cracking of concrete cover and change of bond strength between steel bar and concrete. These mentioned factors greatly influence the mechanical behavior and the load carrying capacity of reinforced concrete beams. On the base of finite element software ANSYS, flexural behavior of corroded reinforced concrete beams are studied. The main research works and the results are as follows:Pull test of corroded steel bars was simulated. Effects of corrosion pits on the stress distribution were studied. Relationship between the nominal yield strength and the maximum corrosion ratio was analyzed. The nominal yield strength of corroded steel bars was discussed with respect to the width and depth and obliquity of the pit.It is studied that the nonlinear finite element model was simulated to analyze corroded reinforced concrete member. 13 corroded reinforced beams were collected and analyzed. Paralleling calculating result with the test proves the reliability of this model. By the aid of finite procedure, flexural behavior of symmetrical corroded reinforced concrete beams and partial ones were studied with respect to different corrosion ratio. The influence of corrosion ratio on the stiffness, the slip between the steel bar and the concrete, the stress of longitudinal steel bar, the appearance of crack and the failure mechanism were studied.Different kinds of calculation method of flexural capacity of corroded reinforced concrete beams were discussed. 6 corroded reinforced concrete beams and other 2 undamaged ones were analyzed on the assumption that they were bonded beams and unbonded ones. An applicable calculation method of flexural capacity of corroded reinforced concrete beams was presented. Finally, a method of calculating flexural stiffness of corroded reinforced concrete beams was given by modifying the expressions in actual criterions.更多还原