Self-Centering Concrete Structures Using Smart Materials

按现行抗震规范设计的结构的主要性能指标是避免人员伤亡和防止结构倒塌。在满足主要标准的情况下，大多数结构在大地震事件中都会遭受破坏。这将导致大量停工维修或在过度损坏的情况下拆除，给建筑物所有者带来经济后果。作为回应，研究导致了自我定心技术的发展，以限制永久性损害。此外，温哥华、维多利亚、多伦多、渥太华、蒙特利尔和魁北克市的建筑存量中有相当大一部分是在20世纪70年代之前建造的，它在地震中很容易受到当前地震需求估计的影响。为改善有缺陷的结构的性能，制定了全球系统修复或地方要素改造的若干方法。最近出现的形状记忆合金(SMA)为开发新的和现有结构的新型自定心结构系统提供了机会。SMAS可以承受显著的非弹性变形，在去除应力后能够恢复到其原始未变形的形状。其他显著特征包括与钢筋相当的强度和位移能力，以及稳定的滞回反应和足够的耗能能力。

The primary performance criterion for structures designed with current seismic codes is to avoid loss of life and prevent structural collapse. Most structures will experience damage during large seismic events while satisfying the primary criterion. This will result in either significant downtime for repairing or demolition in the event of excessive damage posing economic consequences for building owners. In response, research has led to the development of self-centering technologies to limit permanent damage. In addition, a significant percentage of building stock in Vancouver, Victoria, Toronto, Ottawa, Montreal, and Quebec City was constructed prior to the 1970s, and it is seismically vulnerable to current estimates of seismic demand. A number of methodologies have been developed for global system rehabilitation or local element retrofitting to improve performance of deficient structures. The recent emergence of Shape Memory Alloys (SMAs) provides an opportunity to develop novel self-centering structural systems for new and existing structures. SMAs can sustain significant inelastic deformations with the capacity to return to its original undeformed shape after removal of stress. Other salient characteristics include strength and displacement capacities that are comparable to that of steel reinforcement, in addition to stable hysteretic response and sufficient energy dissipation capacity.