【作者】 黄冬明；

【导师】 张爱林；

【作者基本信息】 北京工业大学 ， 结构工程， 2007， 硕士

【摘要】 预应力空间钢结构是预应力技术与空间结构体系相结合而衍生出来的新的结构形式,具有良好的受力性能。弦支穹顶结构是近二十年发展起来的新型预应力空间钢结构体系。通过对下弦索施加预应力,使上层网壳产生与荷载作用相反的内力和位移,增强结构的整体稳定性。与索穹顶体系相比,预应力度较低,而且上层网壳本身是超静定结构,存有一定刚度,索预应力的施加相对简单。弦支穹顶结构实际工程少,施工经验不足,针对此结构的施工过程分析和预应力优化十分必要。本文总结了弦支穹顶结构的特点和国内外研究成果。介绍了弦支穹顶结构施工过程中采用的非线性有限元理论和求解方法。以2008年奥运会羽毛球馆工程建设为契机,对大跨度弦支穹顶结构的施工过程进行理论分析和试验研究。弦支穹顶结构施工成形分析包括找形分析和索张拉过程分析两方面的内容。基于非线性有限元原理,区分结构的初始态、几何零状态和荷载态,指出弦支穹顶的施工过程是结构从几何零状态到初始态的连续变化的过程,采用张力松弛法,通过有限元程序对结构成形过程进行仿真分析。分析了弦支穹顶结构在张拉成形过程中,随着索力的增加而引起的杆件内力、节点位移和不同索之间的预应力变化。通过对同一结构进行了4种张拉方案的杆件内力和节点位移的比较,分析了不同张拉顺序对结构的影响。得出了上弦杆件内力变化均匀和节点位移较小的预应力张拉方案,在此基础上,考虑施工的难易程度,选取了预应力张拉控制值较小的方案。在理论分析的基础上,本文对分析模型进行了张拉试验,通过试验结果与理论计算结果两者的对比分析,验证张拉方案的可行性、理论分析方法的正确性及有限元计算的准确性。试验表明,张拉过程中的弦支穹顶结构内力和变形明显不同于使用阶段,设计中应考虑张拉过程结构的最不利受力情况。更多还原

【Abstract】 Prestressed space steel structure is a kind of new structured style which is produced form the combination prestressed technology and space structure system. It was proved to be of good property of load carrying capacity. Suspend dome structure(SDS) is a new type of prestressed space steel structured style which has developed since the late 20 years. With the prestress acting on lower chord, the internal force and displacement produced by the upper reticulated shell is of opposite direction of loading, which strengthen the overall stability of structure. Compared with the cable dome system. SDS is of lower degree of prestress, furthermore, the upper reticulated shell itself is a statically indeterminate structure, with the rigidity exist in it, the cable prestress is much easier to be be exerted it.As the shortage of practical project of SDS and the lack of construction experience for it, it is necessary to do analysis of construction process and prestress optimization. In the dissertation, the writer summarizes the characteristics of SDS and the achievement which has been got around the world. In addition, it introduces the non-linear finite-element analysis and solution method which are used in the construction process of SDS. Taking the badminton gymnasium project of 2008 Olympics as an example, the writer carries out theoretical analysis and experimental research on the construction process of SDS.The construction forming analysis of SDS consists of shape-finding analysis and the process of cable stretching analysis. On basis of non-linear finite-element principle, for the structure, differentiating the initial state, geometrically zero state and loading state, it change process from geometrically zero state to initial state by adopting the method of tensile relaxation. The finite-element program-Anasys is used in emulating analysis of structural forming process. It analyses the member internal force, joint displacement and the prestressing variation of SDS among different cables with the increase of cable forces in the process of construction forming.By comparison of 4results of stretching schemes which indicate the member internal force and joint displacement, it analyzes the influence of different stretching sequence on structures. Finally, the writer adopt the strentching scheme which an much evener variation of internal force and lower joint displacement in upper chord member could be achieved. On the basis of it, considering the feasibility of construction, the scheme of lower prestressed stretching control value is adopted.Based on the theoretical analysis, this dissertation carries out the stretching test on the model to be analyzed, by the comparison of experiment results and theorerical calculated results, the feasibility of stretching scheme, the validity of theoretical analysis model and the accuracy of finite-element calculation are verified. The experimental analysis indicates that the internal force and deformation of SDS in the process of stretching are obviously different from that of applying phase, thus the most harmful force capacity during the process of stretching should be considered in the design.更多还原