Reducing seismic residual deformations of existing reinforced concrete frames using shape memory alloys

使用形状记忆合金减少现有钢筋混凝土框架的地震残余变形

• 批准号: 261843-2010
• 负责人: Youssef, Maged
• 金额: $ 1.6万
• 依托单位: University of Western Ontario
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=547903
• 关键词: Reducing; seismic; residual; deformations; existing

Previous earthquakes have shown that seismic damage to Reinforced Concrete (RC) frames mainly concentrates in the vicinity of the beam-column joint area. It occurs in different forms including: joint shear failure, flexural failure of beams and/or columns, shear failure of beams and/or columns, and bond slip failure. While frames designed based on older code provisions are susceptible to all mentioned forms of damage, frames designed to current standards are expected to collapse due to flexural failure of their beams. Other forms of damage can co-exist in newly designed frames due to faults in the design and/or construction processes or misuse by occupants (changing the intended use and consequently the applied loads, applying temporary heavy loads, etc.). Retrofitting of existing RC frames has received significant attention from the research community during the past decades. Several retrofitting methods have been proposed. While these methods provide a solution to the flexural and shear deficiencies, they maintain a major deficiency: seismic residual deformations. These deformations result from yielding of the reinforcing bars that is necessary to dissipate the seismic energy. However they complicate post-earthquake retrofitting efforts. The uniqueness of Shape Memory Alloys (SMAs) lies in their ability to undergo large deformations and return to their undeformed shape. The proposed research provides a comprehensive experimental and analytical study that will not only provide solutions to possible deficiencies in existing RC frames, but will also significantly reduce their expected seismic residual deformations. Novel retrofitting techniques that utilize SMAs will be developed. Analytical models capable of predicting the behaviour of the retrofitted structural elements will be developed and validated using experimental tests. These models will be used to analyze full-scale frames to define optimal retrofitting strategies. The proposed research will involve the training of one PhD and three MESc candidates on state-of-the-art experimental and analytical studies. These HQP will be key personnel in shaping the future of smart structures and enhancing the competitiveness of the Canadian construction industry.

以往的地震表明，钢筋混凝土框架的震害主要集中在梁柱节点附近区域。它以不同的形式发生，包括：接缝剪切破坏、梁和/或柱的弯曲破坏、梁和/或柱的剪切破坏以及粘结滑移破坏。虽然根据旧规范规定设计的框架容易受到上述所有形式的损坏，但根据当前标准设计的框架预计会由于梁的弯曲失效而倒塌。由于设计和/或施工过程中的错误或居住者的误用（改变预期用途并因此改变所施加的载荷、施加临时重载荷等），新设计的框架中可能共存其他形式的损坏。在过去的几十年里，现有 RC 框架的改造受到了研究界的极大关注。已经提出了几种改造方法。虽然这些方法提供了弯曲和剪切缺陷的解决方案，但它们仍然存在一个主要缺陷：地震残余变形。这些变形是由钢筋屈服引起的，而钢筋屈服是消散地震能量所必需的。然而，它们使震后改造工作变得复杂。形状记忆合金 (SMA) 的独特之处在于它们能够承受大变形并恢复到未变形形状。拟议的研究提供了全面的实验和分析研究，不仅可以解决现有钢筋混凝土框架中可能存在的缺陷，而且还可以显着减少其预期的地震残余变形。将开发利用 SMA 的新型改造技术。将使用实验测试来开发和验证能够预测改造结构元件行为的分析模型。这些模型将用于分析全尺寸框架，以确定最佳改造策略。拟议的研究将涉及对一名博士和三名理学硕士候选人进行最先进的实验和分析研究的培训。这些总部人员将成为塑造智能结构未来和增强加拿大建筑业竞争力的关键人员。