Seismic performance improvement of buildings with self-centering bracings

自定心支撑提高建筑物抗震性能

• 批准号: 570821-2021
• 负责人: Alam, Shahria
• 金额: $ 5.25万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Alliance Grants
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=722939
• 关键词: Seismic; performance; improvement; buildings; self

Bracings are diagonal structural elements in a building for resisting lateral loads. Traditional bracings essentially carry axial loads. They perform well under axial tension. However, under compression, braces tend to buckle and lose their load carrying capacity. Researchers have proposed buckling restrained bracing, yielding bracing, etc to overcome this buckling problem. However, their disadvantages including: a) heavy weight, b) fabrication difficulty, and c) potential permanent damages after an earthquake. Here, novel bracing systems are proposed to overcome these shortcomings. These systems will be light-weight, and will remain operational with no permanent damages even during a large earthquake. The proposed system will utilize superelastic shape memory alloy (SMA) bars installed inside a cylinder piston, or SMA plates in confined rubberized concrete assembly. A properly designed self-centering braced frame structure is expected to remain operational even after a large seismic event due to its self-centering capability, increasing safety and survivability. It will also provide large savings in reduced repair/replacement work necessary in a post-disaster scenario, and potential for remediation in place rather than demolition. The significance of this research is paramount as this novel technology will help Canada improve the level of safety of building infrastructure during earthquakes. The first stage will involve evaluating the mechanical properties of SMA bars/plates and performance of couplers that connect SMA to steel parts. A series of large-scale quasi-static cyclic and dynamics tests will be performed on bracing elements and braced frames. The generated experimental data will be employed to determine the important parameters that affect the seismic response and limit states, which will help develop performance-based design guidelines for braced frames. The proposed design guidelines will be validated with hybrid simulation tests. The research team will work closely with the partners and design code committee to formulate the appropriate framework with which the proposed design recommendations can be incorporated in the design codes.

支撑是建筑物中用于抵抗横向荷载的对角结构元件。传统支撑主要承受轴向载荷。它们在轴向拉力下表现良好。然而，在压力下，支架往往会弯曲并失去其承载能力。研究人员提出了屈曲约束支撑、屈服支撑等来克服屈曲问题。然而，它们的缺点包括：a）重量重，b）制造困难，c）地震后可能造成永久性损坏。在这里，提出了新颖的支撑系统来克服这些缺点。这些系统重量轻，即使在大地震期间也能保持运行，不会造成永久性损坏。所提出的系统将利用安装在气缸活塞内的超弹性形状记忆合金（SMA）棒，或受限橡胶混凝土组件中的 SMA 板。正确设计的自定心支撑框架结构由于其自定心能力，即使在发生大地震之后也有望保持运行，从而提高安全性和生存能力。它还将大大减少灾后情况下所需的维修/更换工作，并有可能进行就地修复而不是拆除。这项研究的意义至关重要，因为这项新技术将帮助加拿大提高地震期间建筑基础设施的安全水平。第一阶段将涉及评估 SMA 棒/板的机械性能以及将 SMA 连接到钢部件的耦合器的性能。将对支撑元件和支撑框架进行一系列大规模的准静态循环和动态测试。生成的实验数据将用于确定影响地震响应和极限状态的重要参数，这将有助于制定基于性能的支撑框架设计指南。拟议的设计指南将通过混合模拟测试进行验证。研究团队将与合作伙伴和设计规范委员会密切合作，制定适当的框架，将拟议的设计建议纳入设计规范中。