高强高性能空间网格结构体系静力性能及设计方法研究

High-performance structural systems are the only future development direction for large-span spatial steel structures in our country. Additionally, the improvement of building materials promotes advances in structure engineering. Therefore, high-strength steels is introduced to construct high-performance lattice structures in this project. In order to achieve this goal, both numerical simulation and experimental methods are employed hereby, and the relationship between mechanics-based fracture theory and macro mechanical properties of components and structures is also established. Firstly, behavior of high-strength CHS members will be studied and design formulae for checking the strength, global buckling as well as local buckling of high strength CHS members will be proposed; Then based on research results of members, large scale parametric analysis will be performed on large-span steel lattice structures, including single-layer reticulated shells, plate-like space trusses and pipe structures, subjected to detailed load combination conditions; Finally, structure selection suggestions for these spatial structures will be reasonably proposed. Design method for global stability of high-strength single-layer reticulated shells considering the influence of the stiffness of joints will also be recommended. Research results of this project will apply scientific proof and technical support to the development or revision of technical specification for large span lattice structures.

高性能结构体系是我国大跨空间结构工程的未来发展方向，而建筑材料的发展带动建筑结构的飞跃，因此，本项目拟将高强钢材引入空间网格结构体系中，结合试验与精细化数值分析手段，将钢材微细观损伤断裂机理和结构宏观力学性能相联系，从基本构件力学性能入手，建立高强圆钢管构件强度、整体稳定和局部屈曲验算方法，继而以单层网壳、平板网架和管桁架等体系为研究对象，全面考虑设计及施工阶段多种荷载组合，改变结构几何及荷载参数，进行大规模参数分析，系统开展高强高性能空间网格结构体系性能研究，给出各类高强高性能空间网格结构选型建议，形成考虑节点刚度后的高强单层网壳结构整体稳定承载力设计方法，提出合理设计建议，为《空间网格结构技术规程JGJ7-2010》的修订提供科学依据及技术支撑。

基于92例Q460高强钢管母材、热影响区、焊缝材性试验结果，校正了Q460钢材性参数和LOU、VGM和SWDM三种微观机制断裂模型参数；完成9例Q960钢材材性试验，提出了考虑混合强化的剪切修正GTN微观断裂模型，使其可用于Q960钢材的断裂预测；完成20例足尺Q460高强圆钢管轴压、偏压、轴拉及偏拉构件力学性能试验，结合有限元分析结果，明确了高强圆钢管受拉试件的断裂机理，修正了《钢结构设计标准》（GB 50017-2017）中高强圆钢管受压构件整体稳定承载力验算公式；基于58例Q235、Q345、Q460和Q960锈蚀材性或焊接接头试件拉断试验、断口电镜扫描试验，获取了各类钢材的腐蚀形貌特征、腐蚀断裂机理和断裂延性劣化规律，并实现了Q460腐蚀焊接接头的韧脆转变断裂预测；分别以锈蚀单层球壳、单层柱壳和管桁架三类空间网格结构体系为研究对象，以锈蚀率为指标，考虑施工及使用阶段荷载分布特征，结合多尺度精细化建模方法和微观断裂理论，针对近160个不同强度钢材结构算例的承载性能进行数值模拟，基于全寿命设计需求提出三类空间网格结构承载力劣化时变模型和设计建议。本项目研究成果将为《空间网格结构技术规程》（JGJ 7-2010）的修订提供科学依据及技术支撑。