自锚式悬索桥吊索断裂研究

发布时间：2018-11-12 12:38

【摘要】：自锚式悬索桥的主缆锚固于主梁两端,对主梁施加巨大的水平分力,如果支撑主梁的吊索发生断裂,可能导致主梁破坏,进而导致桥梁整体垮塌。随着使用时间的增长,吊索因腐蚀而承载力降低,可能发生突然断裂,使结构发生剧烈振动,导致结构内力变化较大,甚至危及桥梁安全。本文以一座主跨200米的混凝土自锚式悬索桥为研究背景,利用非线性静动力分析方法,采用空间有限元模型,研究了单侧吊索突然断裂对结构受力的影响。研究表明,自锚式悬索桥吊索断裂对相邻吊索的拉力、主梁竖向弯矩、主梁扭矩、索塔顺桥向弯矩、支座反力影响很大,采用动力分析方法计算的结果与采用静力分析方法得到的结果相差甚远。单侧相邻两根吊索相继断裂,会使相邻其他吊索的拉力达到初始拉力的3.0倍以上,如果设计采用的吊索安全系数较低,或吊索出现普遍腐蚀,单侧相邻两根吊索断裂会导致桥梁整体垮塌。及分别研究了主梁抗弯刚度、主梁抗扭刚度、主缆抗弯刚度、主梁自重、主缆自重、主缆垂跨比、吊索距离、跨度及断索时间等参数对断索动态响应的影响。最后,讨论了双吊杆结构对断索后结构动力响应的影响,给出了提高结构安全性的建议。
[Abstract]:The main cable of the self-anchored suspension bridge is anchored at the two ends of the main beam and exerts a huge horizontal force on the main beam. If the sling supporting the main girder breaks it may lead to the destruction of the main beam and then to the collapse of the bridge as a whole. With the increase of service time, the bearing capacity of sling decreases due to corrosion, which may lead to sudden fracture, make the structure vibrate violently, cause great changes in the internal force of the structure, and even endanger the safety of the bridge. Taking a concrete self-anchored suspension bridge with a main span of 200 meters as the research background, using the nonlinear static and dynamic analysis method and the spatial finite element model, the influence of the sudden fracture of one side sling on the structural force is studied in this paper. The research shows that the tension force, the vertical moment of the main beam, the torque of the main beam, the bending moment of the cable tower along the bridge, and the reaction force of the support have great influence on the tension force of the adjacent slings caused by the sling cable fracture of the self-anchored suspension bridge. The results calculated by dynamic analysis method are far from those obtained by static analysis method. If one side and two adjacent slings break one by one, the tension of the adjacent other slings will reach 3.0 times of the initial tensile force. If the safety factor of the slings used in the design is low, or the sling is generally corroded, The rupture of two sling cables on one side will cause the bridge to collapse as a whole. The effects of bending stiffness, torsional stiffness, bending stiffness of main cable, deadweight of main beam, ratio of vertical span of main cable, sling distance, span and time of cable breaking on the dynamic response of broken cable are studied respectively. Finally, the influence of double suspenders on the dynamic response of the structure after cable break is discussed, and some suggestions to improve the safety of the structure are given.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U448.25

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