斜拉结构的鲁棒性及其抗连续倒塌性能研究

In order to reduce the collapse accidents of long-span spatial structures, the robustness, the resistance to progressive collapse and collapse control strategies of the cable-stayed structures are studied in this project. A theoretical method, which is based on the energy and the concept of sensitivity analysis, is proposed to judge the element importance. Then the symmetry of structure is discussed based on the search and evaluation of the symmetry of the truss structures. After that the group theory is used to revise the solution strategies, which increases the computational efficiency. Furthermore, the robustness of cable-stayed structures is studied with the reliability of elements. The vector form intrinsic finite element method is used to simulate the progressive collapse of cable-stayed structures. Then the redistribution law of internal forces and the progressive collapse mechanism of cable-stayed structures after the initial loss of one element are investigated with this program. The proper level and distribution of initial prestress are also discussed. Moreover, some important elements are replaced by buckling restrained members with origami patterns to increase the ductility and the resistance to progressive collapse of cable-stayed structures. Then the effects of purlins and roof panels on the resistance to progressive collapse are also discussed. Finally, the dynamic experiments of the cable-stayed structure and the strengthened cable-stayed structures with collapse control strategies are carried out to validate the numerical simulation method and results. On the basis of results of experiments, some design and construction suggestions are given. It could be concluded that this project has a very important role in the development of long-span space structures in our country.

为减少意外事件下大跨空间结构的倒塌事故，本项目针对应用广泛的斜拉结构，研究其鲁棒性、抗连续倒塌性能和倒塌控制策略。从能量角度出发，结合敏感性分析思想，提出一种构件重要性判断方法；并提出一种空间结构的对称性搜索和判断的方法，利用群论修正求解策略，提高计算效率。在此基础上，结合构件自身的可靠度，进行斜拉结构的鲁棒性研究。利用向量式有限元方法编制斜拉结构连续倒塌数值模拟程序，研究斜拉结构在初始杆件失效后的内力重分布机制与结构连续倒塌机理，并分析合理的初始预应力水平和分布。用折纸型屈曲约束构件代替结构中的关键杆件，提高斜拉结构抗连续倒塌能力；并研究檩条、屋面板对斜拉结构抗连续倒塌能力的作用。为验证连续倒塌数值模拟方法和结果的正确性，进行斜拉结构及利用倒塌控制策略加强后斜拉结构的连续倒塌动力试验研究；在模型试验的基础上，提出相应的设计、施工建议。本项目的完成将对我国大跨空间结构的发展起到重要作用。

为减少意外事件下大跨空间结构的倒塌事故，本项目针对应用广泛的斜拉结构，研究其鲁棒性、抗连续倒塌性能和倒塌控制策略。结合敏感性分析思想，充分考虑到空间网格结构非线性明显的特征，提出了一种基于切线刚度的重要构件判断方法，进一步验证了刚度矩阵的行列式比结构稳定因子更适合作为结构的响应。分别定义了无荷载作用下的构件重要性系数和荷载作用下的重要性系数，通过算例分析了不同支座条件、构件刚度、荷载等级和荷载分布形式对构件重要性的影响及相应的变化规律。将构件失效前后杆件应变能的变化作为结构鲁棒性的衡量指标，提出一种空间结构的对称性搜索和判断的方法，利用群论修正求解策略，提高计算效率。在此基础上，结合构件自身的可靠度，进行斜拉结构的鲁棒性研究。采用全过程动力分析方法和合适的参数，分别对斜拉结构在内索、边索、角索断裂失效的情况下进行抗连续倒塌能力分析。在设计荷载组合下控制结构不同的平均应力比值，得到不同构件截面大小的结构模型，然后对这些模型进行动力放大系数的研究。进行考虑初始缺陷的空间结构连续倒塌静力仿真分析，并编制斜拉结构连续倒塌数值模拟程序，给出了ANSYS中基于等效荷载卸载法的结构抗连续倒塌的具体分析流程，研究结构在初始杆件失效后的内力重分布机制与结构连续倒塌机理，并分析合理的初始预应力水平和分布。提出斜拉结构抗连续倒塌的设计方法，并结合天津梅江会展中心结构的抗连续倒塌设计，探讨大跨空间结构的抗连续倒塌的设计方法，并给出结构抗连续倒塌的措施。设计折纸型屈曲约束构件代替结构中的关键杆件，提高斜拉结构抗连续倒塌能力。本项目的完成将对我国大跨空间结构的发展起到重要作用。