Effects of turbulent wind on exposed flexible structures

湍流风对裸露柔性结构的影响

• 批准号: RGPIN-2018-05237
• 负责人: McClure, Ghyslaine
• 金额: $ 2.26万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=713557
• 关键词: Effects; turbulent; wind; exposed; flexible

Current structural engineering practice continues to rely extensively on static analysis methods for design. The performance-based design approach introduced in recent years still relies heavily on past methods, essentially accepting traditional limit-states design solutions as acceptable solutions, and leaving the issues of security and integrity to the interpretation of designers. Most extreme environmental loads have dynamic effects on exposed structures, and consideration of failure or progressive collapse scenarios cannot generally ignore those dynamic effects when predicting structural response. As widely acknowledged in seismic design of structures, true performance-based design is based on reliable and reasonably accurate response prediction that is rarely feasible with simplified static analysis methods. Wind velocity profiles and pressure loads on exposed structures of rather complex shapes are difficult to predict, which explains why until very recently physical testing in boundary-layer wind tunnel tests has been the preferred method to assess wind loads on structures of complex geometry and components. In situ wind pressure monitoring is also used on important civil projects and numerous experimental studies have been conducted on overhead line conductors by various electric utilities in the world, but it is fair to state that physical wind-tunnel testing results are the main reference material of drag force calculations on structures in most modern codes and standards. The goal of this research program is to assess the accuracy/adequacy of (and eventually improve) the simplified static load methods described in various codes of practice and design guidelines to predict the response of exposed structures to environmental load effects such as turbulent wind, atmospheric icing, and combined wind and ice effects. Canadian regulations are targeted in the process, such as those of the National Building Code of Canada (NBC) - Commentary I Wind Load and Effects and in Canadian Standards Association CSA S37 on Antennas, Towers and Antenna-supporting structures, but the scope is extended to encompass similar methods used in international OHL design standards and for exposed transportation signage structures. The scientific approach will combine a critical review of available experimental results (from wind-tunnel tests and/or monitoring, old and modern-era) and advanced computational mechanics techniques using structural dynamics and fluid dynamics. In particular, fluid-structure interactions will be examined, both for bare and iced flexible structures in simulated realistic turbulent wind conditions. The impact and significance of the research program are far reaching. The immediate results of the research will eventually lead to updating (or confirmation) of the NBC recommendations, which will impact on other national and international design practice.

当前的结构工程实践仍然广泛依赖静态分析方法进行设计。 近年来引入的基于性能的设计方法仍然严重依赖于过去的方法，本质上接受传统的极限状态设计解决方案作为可接受的解决方案，并将安全性和完整性问题留给设计人员解释。大多数极端环境荷载对裸露结构都有动态影响，在预测结构响应时，考虑失效或渐进倒塌场景通常不能忽略这些动态影响。正如结构抗震设计中广泛承认的那样，真正的基于性能的设计基于可靠且相当准确的响应预测，而使用简化的静态分析方法很少可行。形状相当复杂的暴露结构上的风速剖面和压力载荷很难预测，这解释了为什么直到最近边界层风洞测试中的物理测试一直是评估复杂几何结构和部件上的风载荷的首选方法。现场风压监测也应用于重要的土木工程，世界各地电力公司对架空线路导线进行了大量的实验研究，但可以说，物理风洞测试结果是主要参考资料。大多数现代规范和标准中的结构阻力计算。 该研究计划的目标是评估（并最终改进）各种实践规范和设计指南中描述的简化静载荷方法的准确性/充分性，以预测暴露结构对环境载荷影响（例如湍流风、大气）的响应。结冰以及风和冰的组合效果。在此过程中，加拿大法规是针对的，例如加拿大国家建筑规范 (NBC) - Commentary I Wind Load and Effects 以及加拿大标准协会 CSA S37 关于天线、塔和天线支撑结构的法规，但范围有所扩展涵盖国际 OHL 设计标准和暴露的交通标志结构中使用的类似方法。 科学方法将结合对现有实验结果（来自旧时代和现代时代的风洞测试和/或监测）的严格审查以及使用结构动力学和流体动力学的先进计算力学技术。特别是，将检查模拟真实湍流风条件下裸露和结冰柔性结构的流体-结构相互作用。该研究计划的影响和意义是深远的。研究的直接结果最终将导致 NBC 建议的更新（或确认），这将影响其他国家和国际设计实践。