Performance-based seismic design of innovative self-centering connection with modified top and seat angle

在过去的几年里，人们进行了广泛的研究，以开发出地震损伤和残余变形最小的自定心(SC)结构。SC结构首先被引入到预制混凝土结构中。随后，同样的概念被应用于钢框架弯矩结构。在SC节点中，无粘结的后张法(PT)钢绞线或钢筋用于连接结构梁和柱。由于摆动机构的作用，梁柱界面处的间隙打开和关闭提供了相当大的横向荷载作用下的变形能力。当与附加的耗能元件(例如顶座角)相结合时，得到了具有特征旗形迟滞行为的混合系统。使用这种连接类型的结构在水平荷载作用下摇摆，然后恢复到原来的位置。以前的研究表明，由于角长度较短、角厚度不足或材料强度较低，对顶底角的实验研究不足可能会导致SC连接中出现意外行为。此外，目前还没有关于SC节点顶底角修正的试验数据。本研究项目将通过试验和数值研究，将改进的基于顶底角的自定心连接概念应用于钢结构抗弯框架中，以克服上述缺陷。拟议的研究将与将军澳建造公司合作进行。将军澳曾参与建造由钢、混凝土及木结构建造的工业、住宅及商业楼宇。将军澳认为这是在内地下部和不列颠哥伦比亚省北部扩展业务的大好机会，在这些地区，地震危险是设计和细节设计的重要考虑因素。将军澳投资局认为由结构钢制成的预制结构是一个可行的选择，因为与其他结构系统相比，这种系统将使它们获得更好的质量控制和更好的项目管理。该项目的成功完成将使TKI和其他加拿大公司在预制自定心钢结构建筑方面具有优势，并提高抗震性能。

Extensive research has been conducted in past years to develop self-centering (SC) structures with minimal seismic damages and residual deformations. SC structures were first introduced for precast concrete structures. Subsequently, the same concept was applied to steel moment frame structures. In SC connections, unbonded post-tensioned (PT) strands or bars are used to connect the structural beams to columns. Gap opening and closing at the beam-column interface, as a result of the rocking mechanism, provides substantial deformation capacity under lateral loading. When combined with supplemental energy dissipation elements (e.g., top-and-seat angle), a hybrid system with a characteristic flag-shape hysteresis behavior is obtained. Structures using this type of connection sway under lateral load and return to their original positions afterward. Previous research has shown that inadequate experimental research on top-and-seat angles may lead to unexpected behavior in an SC connection due to shorter angle length, insufficient angle thickness, or lower strength of the material. Moreover, there is no experimental data on modified top-and-seat angle in SC connections. The proposed research project will utilize the concept of modified top-and-seat angle-based self-centering (SC) connections in steel moment resisting frames through experimental and numerical studies to overcome the above-mentioned shortcomings. The proposed research will be performed in collaboration with TKI Construction. TKI has been involved in the construction of industrial, residential and commercial buildings made of steel, concrete and timber structures. TKI sees a great opportunity to expand their businesses in the Lower Mainland and Northern British Columbia where seismic hazard is an importation consideration for design and detailing. TKI considers prefabricated structures made of structural steel as a viable alternative since such systems will give them better quality control and improved project management compared to the other structural systems. Successful completion of this project will give TKI and other Canadian companies an edge in prefabricated self-centering steel buildings with improved seismic performance.