斜拉桥结构鲁棒性分析与评价

发布时间：2018-06-17 01:23

本文选题：斜拉桥 + 结构鲁棒性　；参考：《西南交通大学》2017年硕士论文

【摘要】：斜拉桥通常位于交通生命线上的咽喉位置,一旦出现安全问题,将会造成严重的经济损失和社会影响。而随着现代化进程的加深,斜拉桥面临的内外部风险日趋复杂,不相称破坏等"非传统安全"问题开始凸显,常规的结构安全设计方法遭遇严峻的挑战。目前,斜拉桥的安全设计主要基于理想无损状态下的极限状态检算,而极少考虑结构在遭受意外干扰或者局部损伤后的性能。因此,对斜拉桥的结构鲁棒性进行系统性研究已是当务之急,这对提高斜拉桥结构抵抗不相称破坏的能力具有重要的理论意义和工程价值。本文从斜拉桥敏感风险源评估、施工阶段结构鲁棒性、运营阶段抗震鲁棒性和结构鲁棒性评价方法等几个方面展开研究。对斜拉桥在施工阶段和运营阶段的敏感风险源进行了识别和归类,并利用基于ALARP准则的风险矩阵评估方法对典型风险源进行了分级评价。针对斜拉桥结构,研究了偶然事件控制法、增强抗力和延性法、替代荷载路径法及增设消能装置法等四条结构鲁棒性改善方法的适用性。以湖南赤石特大桥为例研究了高墩多塔斜拉桥施工阶段的结构鲁棒性问题。基于赤石大桥高墩多塔结构的施工阶段特征,对遭受局部断索情况的最大双悬臂施工阶段进行了分析,同时研究了设置不同的备用索方案对剩余结构静力响应的优化作用。结果表明,悬臂施工阶段备用索可以提供冗余的荷载传递路径,协助剩余结构更好地进行内力重分布,从而保证斜拉桥结构在遭受局部断索后仍是鲁棒的。以四川雅安大兴二桥为例研究了单索面单塔斜拉桥的抗震鲁棒性问题。基于大兴二桥在分别设置纵、横向阻尼器和抗震墩之后的地震响应,研究了增加消能冗余路径和增强关键构件消能能力这两项措施对斜拉桥抗震鲁棒性的改善作用,进而提出基于塔底弯矩的抗震鲁棒性评价指标。结果表明该指标能初步评定斜拉桥结构的抗震鲁棒性。借鉴建筑结构鲁棒性的研究成果,针对斜拉桥结构鲁棒性量化分析的现状与困境,提出以关键构件或关键节点的静力响应作为斜拉桥结构鲁棒性评价体系的出发点。进而选取包括斜拉索应力、主梁压应力、位移、桥塔弯曲应变能和关键节点构造鲁棒性在内的五项基础性分项指标,借助雷达图的形式,建立了斜拉桥结构鲁棒性综合评价方法及其对应的指标。通过混凝土斜拉桥和钢箱梁斜拉桥的算例,验证了该评价方法及其指标的合理性和适用性。
[Abstract]:The cable-stayed bridge is usually located at the throat of the traffic lifeline. Once the safety problem occurs, it will cause serious economic loss and social impact. With the deepening of the modernization process, the internal and external risks of cable-stayed bridges are becoming more and more complex, and the "unconventional safety" problems such as disproportionate damage begin to appear, and the conventional structural safety design methods are confronted with severe challenges. At present, the safety design of cable-stayed bridge is mainly based on the limit state check under the ideal lossless condition, and the performance of the structure after accidental disturbance or local damage is seldom considered. Therefore, it is urgent to systematically study the structural robustness of cable-stayed bridges, which has important theoretical significance and engineering value in improving the ability of cable-stayed bridges to resist disproportionate damage. In this paper, the sensitive risk source assessment of cable-stayed bridge, the structural robustness in construction phase, the seismic robustness in operation phase and the evaluation method of structural robustness are studied in this paper. The sensitive risk sources of cable-stayed bridges in construction and operation stages are identified and classified. The risk matrix evaluation method based on ALARP criterion is used to evaluate the typical risk sources. Aiming at the cable-stayed bridge structure, the applicability of the methods of accidental event control, enhanced resistance and ductility, alternative load path method and adding energy dissipation device method to improve the robustness of the cable-stayed bridge are studied. The structural robustness of high pier multi-tower cable-stayed bridge in construction stage is studied with the example of Hunan Chishi Bridge. Based on the characteristics of the construction stage of the tall pier and multi-tower structure of the Chishi Bridge, the maximum double cantilever construction stage with local cable breakage is analyzed, and the optimization of the static response of the residual structure with different standby cable schemes is studied. The results show that the spare cable in cantilever construction can provide redundant load transfer path, assist the residual structure to redistribute the internal force better, so as to ensure that the cable-stayed bridge structure is still robust after local cable breaking. The seismic robustness of single cable plane single tower cable-stayed bridge is studied with the example of Ya'an Daxing second Bridge in Sichuan Province. Based on the seismic response of Daxing second Bridge with longitudinal and transverse dampers and seismic piers respectively, the improvement of seismic robustness of cable-stayed bridges by increasing the redundant path of energy dissipation and enhancing the energy dissipation capacity of key components is studied. Then the seismic robustness evaluation index based on tower bottom bending moment is proposed. The results show that this index can preliminarily evaluate the seismic robustness of cable-stayed bridge structures. In view of the present situation and difficulties of quantitative analysis of structural robustness of cable-stayed bridges, the static response of key components or key nodes is proposed as the starting point of the robustness evaluation system of cable-stayed bridges. Then five basic sub-indexes, including cable stress, compression stress of main beam, displacement, bridge tower bending strain energy and the robustness of key node structure, are selected, and the form of radar map is used. The comprehensive evaluation method of cable-stayed bridge structure robustness and its corresponding index are established. Through the examples of concrete cable-stayed bridge and steel box girder cable-stayed bridge, the rationality and applicability of the evaluation method and its index are verified.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U448.27

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