某斜拉桥断索事故及恢复过程的非线性分析

发布时间：2018-03-15 21:54

本文选题：大跨度斜拉桥　切入点：断索事故　出处：《武汉理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：改革开放以后,我国经济总量逐年攀升,同时我国公路交通行业也得到了迅猛发展。其中常用于跨海、跨河地区的斜拉桥的发展对我国公路交通行业的发展做出了较大的贡献。近三十年,斜拉桥因其独特优美的造型以及良好的跨越能力等特点,在我国得到了迅速推广。大跨径斜拉桥属于多次超静定结构体系,而且对其施加常规荷载,斜拉桥同样将出现很大的位移,斜拉桥结构的几何位置也将会出现明显的改变,结构体系的受力特点表现为柔性结构体系,即体现斜拉桥具有显著的几何非线性行为。本文以某大跨度斜拉桥在施工阶段出现的断索事故为工程背景,采用通用有限元软件Abaqus对其断索过程以及恢复过程进行相应简化的几何非线性分析,同时因断索后混凝土出现大范围开裂,所以在以上分析的同时还涉及相应的混凝土材料非线性的分析研究。通过以上计算分析,论述了此斜拉桥断索事故后的力学状态,并且验证了张拉临时索的恢复过程的恢复效果。通过数值模拟发现,大里程方向左侧13、15~22号斜拉索断裂后,大里程方向的斜拉索的索力提升较大,而且左侧的远墩柱端的斜拉索有拉断的趋势;大里程方向主梁出现大幅度的下沉,大里程方向12~16号梁段出现较为严重的扭转,从而主梁左侧下沉更大,同时扭转引起了此区域的混凝土出现大面积的受拉脆性开裂;主塔呈现逆时针的转动(从上往下看)。临时张拉斜拉索抢险后,斜拉桥已基本脱离了危险状态,斜拉索的索力、主梁线型、主塔偏位等均得到了大幅度的恢复。临时索的索力完全恢复后,其内力即变形相比断索前的成桥状态仍有差异,但差异较小,斜拉索的索力、主梁线型、主塔偏位等均得到了进一步的恢复。通过计算与实测结果的对比分析发现,断索后的计算结果与实测结果很接近,而恢复过程的计算结果与实测结果具有不可忽略的差异,主要因为本文是采用混凝土的塑性损伤来模拟混凝土的实际脆性开裂,反向加载时模型的塑性变形不能恢复,而实际的裂纹是可以闭合的。所以计算的恢复过程的斜拉桥的状态与实际状态之间存在差异。
[Abstract]:Since the reform and opening up, the total economic volume of our country has been rising year by year, at the same time, the highway transportation industry of our country has also been developed rapidly, which is often used to cross the sea. The development of cable-stayed bridges across rivers has made a great contribution to the development of highway transportation industry in China. In the last 30 years, cable-stayed bridges have been characterized by their unique beautiful shape and good span ability. The long-span cable-stayed bridge belongs to the statically indeterminate structure system for many times, and when it is subjected to conventional load, the cable-stayed bridge will also have a very large displacement, and the geometric position of the cable-stayed bridge will also be changed obviously. The structural system is characterized by flexible structural system, that is, the cable-stayed bridge has significant geometric nonlinear behavior. In this paper, the cable breaking accident of a long-span cable-stayed bridge in the construction stage is taken as the engineering background. The finite element software Abaqus is used to analyze the geometric nonlinearity of the cable breaking process and recovery process. At the same time, the concrete cracks on a large scale after cable break. Therefore, the above analysis also involves the nonlinear analysis of concrete materials. Through the above calculation and analysis, the mechanical state of the cable-stayed bridge after the cable breaking accident is discussed. Through numerical simulation, it is found that the cable force in the direction of large mileage is higher after the rupture of the cable 131522 on the left side in the direction of large mileage, and the effect of the restoration process of the tensioned temporary cable is verified. Moreover, the cable at the left end of the far pier column tends to be broken, the main girder in the direction of large mileage is sinking by a large margin, and the section of beam 1216 in the direction of long mileage has a more serious torsion, thus the left side of the main beam is sinking even more. At the same time, the torsion caused a large area of tensile brittle cracking of concrete in this area, and the main tower turned counterclockwise (from the top down). After the emergency of the temporary tensioning cable, the cable stayed bridge was basically out of the dangerous state, and the cable force of the cable stayed, After the cable force of the temporary cable is completely restored, the internal force, that is, the deformation of the temporary cable, is still different from the bridge state before the cable break, but the difference is small, the cable force of the stay cable, the line type of the main beam, and so on. The comparison and analysis between the calculated results and the measured results show that the calculated results are very close to the measured ones, while the results of the restoration process are not negligible. The main reason is that the plastic damage of concrete is used to simulate the actual brittle cracking of concrete, and the plastic deformation of the model can not be restored under reverse loading. The actual cracks can be closed, so there is a difference between the calculated state of the cable-stayed bridge and the actual state.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U448.27

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