拱桥在役损伤吊杆破断安全性研究

发布时间：2018-07-31 06:09

【摘要】：吊杆是中下承式拱桥最重要的受力构件,易遭受腐蚀损伤和疲劳累积损伤,极限情况下甚至发生突然破断,威胁结构安全。本文以实际工程为依据,依托于江西省景德镇市瓷都大桥,结合大量的文献资料以及国内外的相关研究成果,通过对工程的现场监测和数值模拟分析相结合的方法,对瓷都大桥采用加劲钢管纵梁进行加固后,建立ANSYS有限元分析模型,围绕吊杆损伤与破断展开研究。本文主要研究内容及成果如下:(1)基于吊杆损伤机理和吊杆损伤过程中拉力与拉应力演变理论,将吊杆损伤模拟成为吊杆有效截面积的减少(断丝数的增加),分析了吊杆损伤后吊杆系统内力重分布的总体趋势,同时研究一根或多根吊杆损伤时全桥吊杆系统拉力的重分布规律。(2)讨论了模拟吊杆破断的各种方法的优劣,并从中选取较为合理的非线性动力模拟方法,通过建立ANSYS有限元模型,开展了综合的参数分析,即对吊杆断裂的持续时间、断裂位置、断裂吊杆数量以及断裂顺序等对结构不同构件的DAF值和DCR的值的影响进行了研究。(3)由于吊杆断裂只对同向相邻吊杆产生比较显著的影响,且吊杆抵抗损伤的能力大小依次为:S7#S4#S1#,因此分别选取S1#吊杆和S7#吊杆进行破损安全分析。同时,以新吊杆更换后的加固桥梁为基础,建立了限元分析模型,选取S6#、S7#和S8#吊杆分步断裂的工况进行吊杆连锁破断分析,并与原吊杆分析数据对比,探究吊杆更换前后的破断安全性能。
[Abstract]:Suspension rod is the most important force member of middle through arch bridge. It is vulnerable to corrosion damage and fatigue cumulative damage, and even breaks suddenly under the limit condition, which threatens the safety of the structure. Based on the actual project and relying on the Jingdezhen Jingdezhen Bridge in Jiangxi Province, this paper combines a large amount of literature and related research results at home and abroad, through the combination of site monitoring and numerical simulation analysis of the project. After reinforcing the stiffened steel tube longitudinal beam, the ANSYS finite element analysis model is established, and the research is carried out around the damage and fracture of the suspender. The main contents and achievements of this paper are as follows: (1) based on the damage mechanism of suspension rod and the evolution theory of tensile force and tensile stress during the damage process, In this paper, the damage of suspension rod is simulated as the reduction of effective cross section area (increase of the number of broken wires), and the general trend of the redistribution of the internal force of the suspender system after the damage is analyzed. At the same time, the redistribution law of the tension of the whole bridge suspension system when one or more suspenders are damaged is studied. (2) the advantages and disadvantages of various methods to simulate the breaking of the suspenders are discussed, and a more reasonable nonlinear dynamic simulation method is selected. Through the establishment of ANSYS finite element model, the comprehensive parameter analysis is carried out, that is, the fracture duration and fracture position of the suspender are analyzed. The effects of the number of broken suspenders and fracture sequence on the DAF value and DCR value of different structural members are studied. (3) because the breakage of the suspender only has a significant effect on the contiguous and adjacent suspenders in the same direction. And the ability of resisting damage of the suspender is 1: S7 #S4 #S1 #S1 #S1, so the S1# and S7# suspenders are selected for damage safety analysis respectively. At the same time, on the basis of the strengthened bridge after the replacement of the new suspender, the finite element analysis model is established, and the working conditions of S6 #S7# and S8# suspenders are selected to analyze the linkage breakage of the suspenders, and the analysis data are compared with those of the original suspenders. To explore the safety of the break before and after the replacement of the boom.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U447;U448.22

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