SEISMIC BEHAVIOR AND DESIGN OF REPLACEABLE STEEL COUPLING BEAMS

For enhanced resiliency of high-rise buildings, a novel type of replaceable steel coupling beam (RSCB) is proposed, which comprises a central "fuse" shear link connected to steel beam segments at its two ends. By appropriately proportioning, inelastic deformation is concentrated in the shear link during a severe earthquake, and the link can be replaced readily after being damaged as specialized link-to-beam connections are adopted. This paper presents the seismic design method and recommendations for the RSCBs, which are backed up by a series of large-scale tests. The strength design and details include the following four aspects: (1) shear link and beam segment, (2) link to-beam connection, (3) RC slab above the RSCB and (4) beam-to-wall connection. In the end, the fragility curves of the RSCBs, corresponding to various damage states and associated repair methods, are developed which provide the criteria for performance-based design and assessment of the RSCBs.