Incremental Engineered Improvements for Enhanced Seismic Performance in Steel Framed Structures

在加拿大，虽然西海岸的地震风险最大，但主要城市中心及其周围的许多其他地区(如蒙特雷亚尔、渥太华、魁北克)容易发生较小但破坏性较小的风险。必须确保建成环境以有效和具有成本效益的方式对所有级别的地震灾害具有弹性。*当代建筑规范中提供的抗震系统在生命安全或防止坍塌的极限状态下进行了良好的性能校准，通常是在非常高强度的地面震动水平下。它们不能保证在其他不太严重但频繁的地面震动水平下具有良好的结构性能。换句话说，目前的设计不能在所有极限状态下提供可靠和足够的结构性能。*拟议的研究旨在开发新类型的支撑元素，这些元素进行了内在的优化，以满足多种性能目标。在这方面，具有不同机械性能的多种钢材料(即普通碳钢、高强度钢和奥氏体型304不锈钢)被用于屈曲抑制支撑元件，以在受到不同水平的地震力时相辅相成，同时能够有效地控制元件的性能和整体结构响应。设计了全面的测试和分析方案。通过将新型支撑类型的性能与传统设计技术进行比较，进行了渐进式改进。因此，建立了重要的设计规则，以在所有极限状态下提供增强的性能并提高可靠性。*研究成果将对既有缺陷框架结构的新建和改造具有一定的参考价值。这项研究的预期结果是重要的，无论是在提供改进的技术方面，还是在培训高素质的人员方面，这些人员将领导其在实践中的实施。

In Canada, while the greatest seismic risk is on the west coast, many other regions in and around major urban centers (e.g. Montréal, Ottawa, Québec) are prone to lesser but damaging risks. It is essential to ensure that the built environment is resilient to all levels of seismic hazards in an efficient and cost-effective manner. ****Earthquake-resistant systems available in contemporary building codes are calibrated for good performance at the life safety or collapse prevention limit states often under very high intensity ground shaking levels. They do not guarantee good structural performance at other less severe but frequent levels of ground shaking. In other words, the current designs do not offer reliable and adequate structural performance across all limit states. ****The proposed research aims at developing new types of brace elements that are inherently optimised to meet multiple performance objectives. In this respect, multiple steel materials with different mechanical behaviour properties (i.e. regular carbon, high strength and austenitic Type 304 stainless steels) are employed in the buckling-restrained brace element to complement each other when subjected to different levels of earthquake forces, while enabling effective control of the component`s behaviour and the overall structural response. Comprehensive testing and analytical programs are designed. Incremental improvements are made by comparing performance of the novel brace types to the traditional design technique. Important design rules are consequently established to deliver enhanced performance at all limit states and to improve reliability. ****The research findings will be beneficial to both new construction and retrofitting of existing deficient framed structures. The anticipated outcome of this research is significant, in terms of both delivering an improved technology and the training of highly qualified personnel who would lead its implementation in practice.**********************************