Seismic performance assessment of eccentrically braced frames with cast steel link elements through hybrid simulations

该项目旨在开发一种现成的高性能铸钢可更换连接件，用于偏心支撑框架(EBF)的设计和施工。作为这些发展的一部分，该项目将涉及准静态循环试验、伪动态混合模拟和高级数值模拟。钢结构EBF为钢结构中常用的抗侧向荷载体系(LLR)提供了一种很好的替代方案，如中心支撑框架和抗弯框架。通过连杆的非弹性作用和偏心支撑的使用，它们在横向刚度、能量耗散和漂移控制之间提供了理想的平衡，同时允许支撑间隔中的建筑开口。然而，目前EBF的设计指南和施工实践并不是没有局限性的。链梁通常是主楼板梁的一部分。这使得EBF的设计是一个迭代的过程，并导致施工困难和维修挑战。铸钢可更换连接件的开发是PI与CAST CONEX的共同愿景，这将解决EBF的设计挑战。 在研究项目中，将制造两种不同容量的拟议产品尺寸并进行测试。将对铸钢可更换连杆进行混合模拟，以执行结构系统的性能评估。此外，还将进行材料试件试验，以校准数值模型和表征所建议的铸钢连杆的低周疲劳寿命模型，并随后制定设计准则。拟议的研究是为最终确定拟议系统的发展而采取的必要步骤。它将使研究团队和行业合作伙伴为工程界提供适用于不同结构和不同高度的各种产品。

The proposed project aims to develop an off-the-shelf high-performance cast steel replaceable link to be used in the design and construction of eccentrically braced frames (EBFs). As part of such developments, the project will involve quasi-static cyclic tests, pseudo-dynamic hybrid simulations, and advanced numerical simulations. Steel EBFs provide a great alternative to the commonly used lateral load resisting systems (LLRS) in steel structures such as concentrically braced frames and moment-resisting frames. Through inelastic action of the link and use of eccentric braces, they provide an ideal balance between lateral stiffness, energy dissipation, and drift control, while allowing for architectural openings in the braced bays. Current design guidelines and construction practices of EBFs, however, are not without limitations. The link beam is often a segment of the main floor beam. This makes the design of EBFs an iterative process and leads to construction difficulties and repair challenges. The development of cast steel replaceable links is a vision that the PI shares with Cast Connex, which will address the design challenges with EBF. In the research project, two sizes of the proposed product with different capacities will be fabricated and tested. Hybrid simulations on cast steel replaceable links will be carried out to perform a performance assessment of the structural system. Besides, material coupon tests will be performed to calibrate the numerical models and characterize the proposed cast steel links' low-cycle fatigue life models, followed by the development of design guidelines. The proposed research is a necessary step towards finalizing the development of the proposed system. It will enable the research team and the industry partner to offer the engineering community a wide range of products suitable for different structures and buildings of different height.