Seismic Behavior of a Hybrid Moment-Resisting Frame with Replaceable Energy Dissipation Angles

The primary focus of this research was the targeted replaceability in steel moment-resisting frames. For this purpose, a hybrid moment-resisting frame with replaceable energy dissipation angles (HMRF-REDA) is proposed with the advantage of cost-effective and easy replacement work. The system consists of energy dissipation bays (EDBs) equipped with fuse connections and recentering bays (RBs) made of high strength steel (HSS). The fuse connections are located in beams of EDBs with connection plates at the top flange and steel angles at the bottom flange. Inelasticity is expected to be restrained in the angles during a wide deformation range, allowing repair by replacing the angles. In this research, shaking table tests were performed to investigate the seismic performance of the HMRF systems and in particular, the on-site fuse replacement feasibility in a complete structural system. The specimen was comprised of two parallel one-second scaled, three-story hybrid moment-resisting frames designed with fuse connections. The results demonstrated that HMRF-REDA exhibited a multi-stage yielding sequence with damage restricted to the fuse elements for the expected deformation range. The HSS frame members were able to fully recenter the structure that experienced an inner-story drift up to 0.0235 rad. Two on-site fuse replacement operations were implemented within the complete structural systems and proved to be feasible and easy to operate. The fuse replaced frame model achieved a similar subsequent elastic and inelastic performance when it experienced a preceding drift up to 0.0184 rad.