Hysteretic model for shear-type friction steel truss coupling beams

Conventional steel coupling beams suffer from irreparable plastic damage after earthquakes, requiring costly member replacement. To address this issue, this study proposes a shear-type friction steel truss coupling beam (SFTCB) utilized in coupled wall systems. The SFTCB transforms the inelastic deformation at the diagonal web members into the sliding of asymmetric friction connections (AFC). By confining energy dissipation to the replaceable AFC, the main body of the SFTCB remains elastic during earthquakes. Post-earthquake recovery of coupling beams simplifies to AFC replacement. Moreover, the SFTCB decouples stiffness and strength, thereby exhibiting an independent and flexible design process. Firstly, the configuration and design concepts of the SFTCB were introduced. Sequentially, quasi-static tests were conducted to validate the seismic performance of the SFTCB. Based on both theoretical and test hysteretic curves, a hysteretic model was then proposed for the SFTCB. The model integrates six parameters, half derived theoretically and half calibrated empirically. Finally, the proposed model and the stiffness-strength decoupling mechanism were validated through finite element (FE) parametric analysis. The FE results validate the stiffness-strength decoupling mechanism and indicate that the theoretical and empirical parameters of the proposed model have acceptable deviations within 10 % and 18 %, respectively Therefore, the proposed hysteretic model can accurately predict the SFTCB’s hysteretic behavior and is suitable for seismic design of the SFTCB.