Seismic Performance of Steel Frames with Replaceable Energy-Dissipating Slit Joints: Experimental and FE Analyses

Abstract

Steel moment-resisting frames are widely used in seismic regions, but conventional beam–column connections often suffer from concentrated damage and difficult post-earthquake repair. To address these issues, this study proposes a novel replaceable energy-dissipating slit beam–column joint for steel frames. To enhance structural energy dissipation efficiency, mitigate seismic damage, and enable rapid post-earthquake repair, the joint utilizes connectors as energy-dissipating elements such that plastic deformation is confined to these connectors while main beams and columns remain elastic throughout the loading history. A quasi-static test was conducted on the proposed joint. The test results indicate that the hysteresis loops are full and fusiform, demonstrating excellent energy dissipation capacity. The joint exhibits ductility coefficients of 6.30 and 5.27 under positive and negative loading, respectively, and the equivalent viscous damping coefficient remains above 0.30 after a rotation of 0.025 rad. Furthermore, plastic damage is primarily sustained by the connectors, with no evident yielding observed in other structural members. To further investigate the joint, it was applied to a three-story, four-bay, three-span steel frame for finite element analyses. Compared with a conventional rigid joint frame, the proposed joint frame under rare earthquakes reduces roof displacements by 20.97% (with the X-direction as the primary direction) and 16.23% (with the Y-direction as the primary direction), and maximum interstory drift ratios by 18.06% (with the X-direction as the primary direction) and 15.55% (with the Y-direction as the primary direction), while satisfying the code-specified limits of 1/250 for elastic and 1/50 for elastoplastic interstory drift ratios, thereby indicating its superior seismic performance.