新型大矢高气承式膜结构风致灾害机理及抗风设计方法研究

In recent years, a new type of large vector height air-supported membrane structure has been widely used in China because of its good function of separating haze and anti-pollutant diffusion. The existing wind-resistant technology is more and more difficult to meet the needs of its span growth, and collapsing accidents caused by strong winds occur from time to time. The following studies are planned for this project: 1) Improving the similar theory of aero-elastic model test of air-supported membrane structure: Establishing the similarity criterion, and propose a method to evaluate and correct the response error caused by similar parameter deviation. 2) Using the non-contact dynamic displacement and strain measuring system to carry out aero-elastic model wind tunnel tests of typical air-supported membrane structures, combines CFD numerical simulation method, to reveal the wind-induced disaster mechanism of the structure: quantitative analysis of the influence of vibration and deformation on the wind load of the membrane; clarify the reasons, conditions and characteristics of aero-elastic instability; give the definition of aero-elastic instability and propose a method to determine the critical wind speed; put forward the anti-instability control measures. 3) Finally, propose the wind-resistance design method of air-supported membrane structures and realize the equivalent static analysis method that considering the fluid structure interaction effect. Give the wind load coefficients, dynamic coefficients and its adjustment factor, Fluid-Structure Interaction (FSI) effect factors of typical air-supported membrane structures for design reference. Verify the effectiveness of the equivalent static analysis method by field tests.

近年来，一种新型大矢高气承式膜结构因其良好的隔绝雾霾、防污染物扩散等功能在我国得到广泛应用。现有抗风技术越来越难以满足其跨度增长的需要，强风作用下的结构倒塌事故时有发生。本项目拟进行以下研究：1）完善气承式膜结构气弹模型试验相似理论：建立相似准则，提出相似参数偏差引起的响应误差的评估与修正方法。2）运用非接触式动态位移、应变测量系统进行典型气承式膜结构气弹模型试验，结合CFD数值模拟方法，揭示结构的风致灾害机理：量化分析振动和变形对结构表面风荷载的影响，明确气弹失稳发生的原因、条件、特征，给出气弹失稳的定义及临界风速的确定方法，提出防失稳控制措施。3）最后，提出气承式膜结构抗风设计方法，实现考虑流固耦合效应的等效静力分析方法，给出可供设计参考的典型气承式膜结构的风荷载体型系数、响应风振系数、风振系数调整因子和流固耦合影响因子，通过实测验证等效静力分析方法的有效性。

新型大矢高气膜建筑结构具有防治雾霾双重功效，在我国具有广阔的应用前景，但抗风研究不足，导致结构在风荷载作用下破坏的事故时有发生。本项目首先建立了气膜结构气弹模型试验应满足的相似准则，然后通过数字图像相关技术，测量了三种不同形状的典型气膜结构气弹模型在不同风速、不同风向角下的全场动态位移应变，研究了结构响应随风速变化规律，探讨了结构发生气弹失稳的可能性。通过刚性模型测压试验，测量了常见不同矢跨比的典型气膜结构在不同风向角下的动力响应时程，结合非线性动力时程分析方法，明确了气膜结构发生风致灾害的机理；在此基础上，提出了考虑流固耦合效应的抗风设计方法，给出了可供设计参考的响应风振系数，与测试结果相比验证了设计方法的有效性。此外，课题组还研究了两个矩形平面投影气膜结构并列放置时，间距变化、风向角变化对气膜结构风荷载、风振响应的干扰效应，给出了可供设计参考的干扰因子。最后，提出了一种新型高抗风性能气膜结构-主索嵌入式斜向交叉索网气膜结构，能有效防止索滑移；将气膜结构用于冰雪景观建筑施工模板，拓展了气膜结构的新用途。