往复荷载作用后锈蚀钢筋混凝土梁承载力研究

发布时间：2018-04-06 01:23

本文选题：钢筋混凝土梁　切入点：承载力　出处：《辽宁工程技术大学》2014年硕士论文

【摘要】：在钢筋混凝土结构或构件中,锈蚀和疲劳双破坏因素的共同作用是引起结构或构件承载力下降、发生破坏的严重因素。本文对往复荷载作用后锈蚀钢筋混凝土梁承载力进行理论分析和数值模拟,具体工作如下：首先,对现有锈蚀钢筋混凝土梁疲劳承载力研究进行总结分析,并在此基础上展开往复荷载作用后锈蚀钢筋混凝土梁承载力的理论分析。分析中仅考虑钢筋在锈蚀及疲劳因素作用下性能的退化。先推导出锈蚀因素影响下钢筋混凝土梁承载力计算模型,之后推导出往复荷载作用下钢筋混凝土梁承载力计算模型,进而结合二者推导出往复荷载作用下锈蚀钢筋混凝土梁承载力计算模型。其次,运用ABAQUS有限元软件进行无锈蚀钢筋混凝土梁的承载力数值模拟和往复荷载作用后锈蚀钢筋混凝土梁承载力的数值模拟后,通过无锈蚀钢筋混凝土梁的数值模拟结果与其对应的试验结果相对照,来验证有限元方法进行数值模拟方法的有效性。再通过往复荷载作用下锈蚀钢筋混凝土梁承载力的数值模拟结果与前文推导出的理论计算结果相对照,以此来验证理论推导模型的合理性。之后根据不同锈蚀率不同循环次数往复荷载作用后的数值模拟结果来分析锈蚀率及往复荷载循环次数对钢筋混凝土梁的屈服荷载与极限挠度的影响。研究结果表明：屈服荷载值随钢筋锈蚀率和往复荷载循环次数的增加而减小,极限挠度值随钢筋锈蚀率和往复荷载循环次数的增加而增大；钢筋锈蚀率及往复荷载循环次数对屈服荷载的影响程度比较接近,但钢筋锈蚀率对极限挠度的影响大于往复荷载循环次数的影响。最后,将应力比引入分析中,进行不同应力比往复荷载作用后锈蚀钢筋混凝土梁承载力的数值模拟。当钢筋疲劳破坏最大应力不变时,增大应力比,钢筋应力幅值减小,从而导致钢筋疲劳寿命增加,进而导致钢筋在相同循环次数的往复荷载作用后其强度和截面面积减小程度变小,从而影响钢筋混凝土梁的承载性能。分析得出：钢筋混凝土梁的屈服荷载受往复荷载应力比影响显著,应力比对屈服荷载的影响程度大于锈蚀率的影响,而钢筋混凝土梁的极限挠度受往复荷载应力比的影响在应力比较小时显著,较大时变小,应力比与锈蚀率对极限挠度的影响程度基本一致。
[Abstract]:In reinforced concrete structures or members, the joint action of corrosion and fatigue failure factors is the serious factor that leads to the decrease of the bearing capacity and the failure of the structures or members.In this paper, the bearing capacity of corroded reinforced concrete beams subjected to reciprocating loads is analyzed theoretically and numerically. The specific work is as follows: firstly, the fatigue bearing capacity of corroded reinforced concrete beams is summarized and analyzed.On this basis, theoretical analysis of the bearing capacity of corroded reinforced concrete beams under reciprocating loads is carried out.In the analysis, only the degradation of steel bar performance under the action of corrosion and fatigue is considered.The calculation model of the bearing capacity of reinforced concrete beams under the influence of corrosion factors is first derived, and then the calculation model of the bearing capacity of reinforced concrete beams under reciprocating loads is derived.Furthermore, the calculation model of bearing capacity of corroded reinforced concrete beams under reciprocating load is derived.Secondly, the numerical simulation of the bearing capacity of corrosion-free reinforced concrete beams and the numerical simulation of the bearing capacity of corroded reinforced concrete beams under reciprocating loads are carried out by using ABAQUS finite element software.The validity of the finite element method is verified by comparing the numerical simulation results of the corrosion-free reinforced concrete beams with the corresponding experimental results.Then the numerical simulation results of the bearing capacity of corroded reinforced concrete beams under reciprocating loads are compared with the theoretical results derived above to verify the rationality of the theoretical model.The effects of corrosion rate and cyclic number of reciprocating loads on yield load and ultimate deflection of reinforced concrete beams are analyzed according to the numerical simulation results of reciprocating loads with different corrosion rates and cycles.The results show that the yield load value decreases with the increase of the corrosion rate of steel bar and the number of cycles of reciprocating load, and the ultimate deflection value increases with the increase of corrosion rate of steel bar and the number of cycles of reciprocating load.The corrosion rate of steel bar and the number of cycles of reciprocating load have a close effect on yield load, but the effect of corrosion rate of steel bar on limit deflection is greater than that on cyclic times of reciprocating load.Finally, the stress ratio is introduced into the analysis, and the numerical simulation of the bearing capacity of corroded reinforced concrete beams under reciprocating loads with different stress ratios is carried out.When the maximum stress of steel bar fatigue failure is constant, the stress amplitude decreases with the increase of stress ratio, which leads to the increase of fatigue life of steel bar.Then, the strength and cross-section area of steel bar decrease after the reciprocating load of the same cycle times, which affects the bearing capacity of reinforced concrete beam.The results show that the yield load of reinforced concrete beam is significantly affected by the ratio of reciprocating load to stress, and the effect of stress ratio is greater than that of corrosion rate.However, the ultimate deflection of reinforced concrete beams is significantly affected by the ratio of reciprocating load and stress. The stress ratio and corrosion ratio have the same effect on the ultimate deflection.
【学位授予单位】：辽宁工程技术大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU375.1

【参考文献】