Modelling and simulating the extreme wind effect on structures

在过去20年里，加拿大每年记录的强风事件超过221起，它们对关键基础设施的影响直接导致受影响地区人口的安全水平下降。大型结构，如大跨度桥梁，被认为比高层建筑、塔楼和输电线路更能抵御强风的影响；然而，这些结构的复杂性意味着其暴露的结构元素，如桥面、塔楼和电缆更容易受到破坏。桥梁各构件和整个桥梁结构的气动稳定性验证已成为大跨度桥梁设计过程的标准标准；然而，目前几个国际研究界正在开展开发和实施新一代双桥面和三层桥面桥梁的全球趋势，这些桥梁具有将主跨尺寸扩大到2000米以上的突出优势。本课题中的加拿大代表包括由申请人提出的四重桥面原型，该原型经过常规实验方法测试，证明具有更好的空气动力稳定性。然而，对于具有复杂桥面结构的大跨度桥梁，要通过极风安全标准验证，必须认真制定和实施新颖而通用的试验和动力稳定标准。 目前的研究计划旨在利用多功能风致损伤模拟器(WDS)开发新的实验和分析工具，并通过开发集成有限条法(IFSM)来分析具有复杂(双、三和四)桥面结构的大跨度桥梁的极端空气动力响应。IFSM方法代表了著名的有限元方法的替代品，后者能够对材料属性和复杂的几何形状进行详细的建模，更重要的是，它允许结构-风相互作用的发展。 由于IFSM在结构空气动力响应中的应用是一个新的研究领域，将使用新技术来模拟桥梁构件(如桥面、缆索和塔架)上的强风效应，以验证分析结果。WIDS设备能够重现极端大风造成的破坏，并可以重现建筑物经历严重风暴影响的方式。在极端风实验条件下获得的临界结果将为开发甲板缆索和塔架气动特性的IFSM模块提供参考。 作为拟议研究的一部分，至少六名研究生和三名本科生将接受培训，使他们能够发展设计和测试优秀桥梁结构的特殊技能。

Over the past 20 years, more than 221 severe wind events were recorded yearly in Canada, and their effects on critical infrastructure have direct consequences on decreasing safety levels for populations in affected areas. Massive structures, such as long-span bridges, are considered more resilient to strong wind effects than high-rise buildings, towers, and electrical transmission lines; however the complexity of these structures implies higher vulnerability of their exposed structural elements such as bridge decks, towers and cables. The aerodynamic stability verification of each element of bridges, and of the entire bridge structure, became a standard criteria for the long-span bridges design process; however a global tendency of developing and implementing a new generation of twin and triple deck bridges, which have the outstanding advantage of extending the main spans dimensions to more than 2,000 m, is currently undertaken by several international research communities. The Canadian representation in this topic consists in the quadruple bridge deck prototype, proposed by the applicant, which was tested by conventional experimental methods, and proved to have better aerodynamic stability. However, for long-span bridges with complex deck configurations, to pass extreme winds safety criteria verification, novel and versatile tests and dynamic stability criteria must be diligently elaborated and carried out. The current research program aims at developing new experimental and analytical tools using the versatile Wind-induced Damage Simulator (WIDS) and by developing the integrated finite strip method (IFSM) for analyzing extreme aerodynamic responses of long-span bridges with complex (twin, triple and quadruple) deck configurations. The IFSM method represents a substitute for the well-known FE Method, which enables detailed modelling of material properties and complex geometries, and, more importantly, it allows for structure-wind interaction development. Because the application of the IFSM to aerodynamic responses of structures is a new research area, the analytical results will be validated using new techniques to simulate severe wind effects on scaled bridge elements such as bridge decks, cables, and towers. The WIDS Facility is able to reproduce the damage induced by extreme winds, and can recreate the ways in which structures experience effects of severe windstorms. The critical results obtained under extreme wind experimental conditions will serve as reference for developing the IFSM modules for the aerodynamic behaviour of the deck cables, and towers. At least six graduate students and three undergraduate students will be trained as part of the proposed research, enabling them to develop exceptional skills in designing and testing outstanding bridge structures.