PERFORMANCE-BASED PLASTIC DESIGN METHOD FOR HIGH STRENGTH STEEL FRAMED-TUBES WITH END-PLATE CONNECTED SHEAR LINKS

High-strength steel framed-tube structures with end-plate connected shear links (SFTSs) is an innovative high-rise earthquake-resilient structural system. It improves the seismic performance of conventional steel framed-tube structures and achieves rapid post-earthquake repairability. Since the traditional seismic design method based on the current code cannot accurately predict and control the inelastic performance of the structure, the damage of the structure may be concentrated on individual floors, thus forming a weak layer. To design a structure with an ideal failure mode, we propose a specific four-level seismic fortification objective for SFTSs, which requires no damage under frequent earthquakes, replaceable under the design and rare earthquakes, and collapse prevention under very rare earthquakes. A trilinear capacity curve considering multiple performance objectives under different seismic levels was adopted in the proposed performance-based plastic design method of SFTSs. The effects of higher mode shapes and post-yield stiffness were also considered. A 30-story SFTS model was designed according to the proposed method. Nonlinear time history analyses of the model were performed under 20 selected ground motions using OpenSees. The results demonstrate that the model designed with the proposed design method exhibited the intended failure mode and achieved the performance objectives under the different seismic levels, indicating excellent seismic performance of the model. The effectiveness of the proposed performance-based plastic design method of SFTSs was verified, which can be applied to the practical engineering design of SFTSs.