芜湖长江大桥梁体挠度随拉索损伤变化规律研究

发布时间：2018-10-18 20:24

【摘要】：拉索是斜拉桥结构的重要组成部分，大量事故表明，拉索的损伤通常会引起桥梁结构力学特性的改变，尤其是拉索索力和主梁挠度的改变，最终威胁到桥梁的安全。由于拉索结构的复杂性以及在役拉索损伤理论研究的相对不完善性，至今还未形成较为全面的针对拉索损伤识别及安全评估的研究方法。本文以芜湖长江大桥主航道区矮塔斜拉桥部分为研究背景，分析梁体挠度随拉索损伤的敏感性，进而探讨基于挠度监测拉索损伤方法的可行性。主要研究内容有：首先，利用ANSYS建立了芜湖长江大桥的三维有限元模型，并且以实测数据为依据进行了模型修正，得到准确、可靠的计算模型。然后，通过折减拉索面积的方法模拟拉索损伤，分析单索损伤或双索同时损伤10%、30%、50%时无车过桥状态下梁体挠度的变化规律和特点。最后，对比不同列车荷载作用下梁体挠度的变化规律和特点，以及单机荷载和不同损伤组合作用下梁体挠度的变化规律和特点。通过拉索损伤前后的对比分析发现：拉索发生损伤后，损伤索锚固节点处挠度变化明显(出现极值点)，且损伤拉索两侧附近节点的挠度增幅不同，损伤拉索相比邻近的短索对应的挠度变化增幅较大，而与邻近长索对应的挠度变化增幅相近；列车荷载作用对拉索损伤区域梁体挠度变化具有明显的放大作用，同时还发现，损伤拉索锚固节点的挠度随拉索损伤率的增大而线性增长。由此可见，对拉索损伤情况，通过对应于损伤索锚固节点（极值点）以及附近节点的挠度变化趋势不仅可识别损伤索的位置，，还可识别损伤的程度。
[Abstract]:Cable is an important part of cable-stayed bridge structure. A large number of accidents show that the damage of cable usually leads to the change of mechanical properties of bridge structure, especially the change of cable force and deflection of the main beam, which ultimately threatens the safety of the bridge. Due to the complexity of the cable structure and the relative imperfection of the theoretical study on the damage of the cable in service, there has not been a comprehensive research method for the damage identification and safety assessment of the cable up to now. In this paper, the sensitivity of beam deflection with cable damage is analyzed based on the research background of low tower cable-stayed bridge in Wuhu Yangtze River Bridge main waterway area, and the feasibility of cable damage monitoring method based on deflection is discussed. The main research contents are as follows: firstly, the 3D finite element model of Wuhu Yangtze River Bridge is established by using ANSYS, and the model is modified based on the measured data, and an accurate and reliable calculation model is obtained. Then, the damage of cable is simulated by reducing the area of cable, and the variation law and characteristics of beam deflection under the condition of no vehicle crossing bridge are analyzed under the condition of single cable damage or double cable damage at the same time. Finally, the variation law and characteristics of beam deflection under different train loads are compared, as well as the variation law and characteristics of beam deflection under the combination of single load and different damage. Through the comparative analysis before and after the cable damage, it is found that after the cable damage, the deflection of the damaged cable Anchorage joint changes obviously (the extreme point appears), and the increase of the deflection of the joint near the two sides of the damaged cable is different. The deflection change of damaged cable is larger than that of adjacent short cable, and the increase of deflection is similar to that of adjacent long cable, the train load has obvious magnification effect on the deflection change of beam body in the damaged area of cable, and it is also found that the effect of train load on the deflection change of beam body in the damaged area of cable is obvious, and it is also found that, The deflection of damaged cable Anchorage joints increases linearly with the increase of cable damage rate. Thus it can be seen that the damage of cable can be recognized not only by the position of the damaged cable but also by the deflection change trend of the node corresponding to the anchor node (extremum point) and the nearby node of the damaged cable.
【学位授予单位】：石家庄铁道大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U448.27;U441.4

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