Self-Centering Concrete Structures Using Smart Materials

现行抗震规范设计结构的主要性能标准是避免生命损失和防止结构倒塌。大多数结构在满足基本准则的情况下，在大地震事件中仍会遭受破坏。这将导致大量的停机时间进行维修或拆除，以防过度损坏给业主带来经济后果。因此，研究导致了自定心技术的发展，以限制永久性损伤。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很大一部分是在20世纪70年代之前建造的，这些建筑在地震中很容易受到当前地震需求估计的影响。为了改善缺陷结构的性能，已经开发了许多方法用于全球系统修复或局部元件改造。形状记忆合金（sma）的出现为新的和现有的结构提供了开发新的自定心结构系统的机会。sma可以承受显著的非弹性变形，并在去除应力后恢复到原始的未变形形状。其他显著特点包括强度和位移能力与钢筋相当，除了稳定的滞回响应和足够的能量耗散能力。

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.