Optimal Placement of Damage-Free Self-centring Links in Steel EBFs

Low-damage self-centring steel structures have been proposed over the last few decades as seismic-resistant frames capable of achieving seismic resilience during strong earthquakes. Recently, the authors proposed a damage-free self-centring link as an innovative seismic link in steel eccentrically braced frames and proved its effectiveness through experimental and numerical analyses. However, there is a lack of generalised design recommendations for self-centring structures, and follow-up studies showed that their peak deformations are increased compared to conventional structures. This study investigates the opportunity to optimise the location of SC-links in EBFs to enhance the seismic performance of structures in terms of both peak and residual deformations. A 6-story, 3-bay case-study structure has been designed and successively upgraded with SC-links. Numerical models have been developed in OpenSees, and Incremental Dynamic Analyses have been performed to investigate and compare their seismic performance. The seismic responses of the case-study structures equipped with different SC-links layouts have been successively evaluated, providing some considerations regarding their optimal distributions. A Genetic Algorithm implemented in Matlab, interfacing with OpenSees for Non-Linear Time-History Analyses, has been validated using a Brute-Force Approach. The results demonstrate that integrating a limited number of SC-links in steel EBFs can enhance their seismic performance, highlighting the efficiency of the proposed GA.