单层平面索网结构以其建筑结构简洁、轻盈美观、通透性好等优点在建筑玻璃幕墙中得到了较广泛的应用，由于该结构具有刚度小、质量轻、阻尼小等特点，故对风荷载和风振尤为敏感，目前关于索网结构的抗风设计理论和方法的研究还相当薄弱，现行规范JGJ102-2003（规程CECS127:2001）中的相关规定也不完善，因此，深入开展索网结构的风振特性和抗风设计方法研究具有十分重要的理论意义和工程实用价值。本文结合理论分析、试验研究和数值计算等多种手段，对单层索网结构的动力特性、风振响应特性进行了较系统的研究，充分考虑索网结构的几何非线性、风振特征和风荷载等参数影响，提出了该类结构的实用抗风设计方法。本文主要完成了以下几方面工作：（1）对单层平面索网结构的动力特性进行了较系统的理论研究，探讨了索网的预应力和几何位形变化，索与玻璃的协同作用等因素对结构自振特性的影响；基于连续化理论采用薄膜比拟法，根据能量守恒原理，建立了索网非线性自振频率的解析表达式，并采用数值计算对公式进行了验证。（2）基于索网动力特性的理论分析，结合工程实例，进行了几何比例为1:10的单层索网模型动力特性试验研究，实测了索网在不同预应力下的自振频率，对安装玻璃前后的结构频率进行了比较，试验结果与有限元计算结果吻合较好。（3）采用随机模拟时程分析方法，系统地研究了风荷载作用下主体结构与单层索网的相互作用问题。通过对比考虑主体结构影响前后索网风振响应特性的变化表明，一般情况下索网的风振响应分析可以不考虑主体结构的影响。（4）通过考察索网的几何非线性对其风振响应和静力风效应的影响，提出了一种考虑单层索网结构非线性影响的风振响应频域分析方法，并采用该方法对索网结构风振响应特性进行了系统研究。（5）根据单层索网结构的非线性力学特征和风振响应特性，推导了计算索网结构等效静力风荷载的解析表达式，通过系统分析，给出了单层索网结构的实用抗风设计方法和非线性索网结构荷载风振系数的实用计算公式。
Monolayer cable net has been widely used in many point-supported glass facades by its virtue of of simple configuration, elegant appearance and excellent transparency etc. However, the prestressed cable net is extremely sensitive to fluctuating wind loads and wind-induced vibration, since it has less damping, lower stiffness and light weight. The research on its wind-resistant behavior and design method is still inadequate, in addition, the relevant provisions covered in current code JGJ102-2003 and specification CECS127: 2001 for glass curtain wall are limited. Therefore, it is of vital importance in theory and engineering practice to further understand the wind-induced performance and design methods of monolayer cable net. Theoretical analysis, experiments and numerical simulation have been carried out hereby to investigate the dynamic behavior, wind-induced performance on this type of structures. The geometric nonlinear properties, wind-induced vibration characteristics and parameters interrelated with wind loads are extensively considered. A practical wind-resistant design method has been proposed in this paper. The main research work covered in this paper includes:(1) The dynamic properties of monolayer planar cable net is systematically analyzed in theory. The effects of some important factors have been discussed herein, such as prestress, geometric configuration of cable net, and the behaviors of cable net cooperating with glass panels. What’s more, the explicit formulas for the nonlinear frequencies of cable net are derived by assuming the net as a continuous membrane based on the principle of energy conservation. The credibility of the formulas is verified with some numerical examples.(2) In terms of the theoretical analysis on the dynamic properties of cable net, the experiment on a 1/10-scale cabel net model of a practical project has also been carried out. The natural frequencies at different pre-stretching levels are measured, and the frequencies of cable net before the installation of glass panels are also compared with those after the installation. The results of experiment agree well with those of finite element analysis (FEA).(3) The interaction between cable net and buildings that the cable net system attached to has been systematically studied through nonlinear time-domain analysis with random simulation. Wind-induced response of cable net cooperating with the building are compared with that of cable net alone, and it is concluded that the wind-induced analysis of cable net can be independently carried out without the inclusion of the buildings for conventional engineering application.(4) The effects of nonlinear behavior of cable net on wind-induced vibration characteristics and the performances of the static response have been studied. A method in frequency domain is proposed to analyze the wind-induced response of monolayer cable net, which considers the geometric nonlinear effects on wind-induced response of cable net in a simple way. Thus the fundamental characteristics of wind-induced response of cable net are systematically analyzed with the method.(5) The explicit expressions for the equivalent static wind loads on monolayer cable net are deduced, based on the characteristics of its nonlinear mechanism and wind-induced response. Finally, the practical wind-resistant design method and dynamic coefficients for wind loads are proposed for nonlinear flexible cable net through extensive and systematic analysis.
