The fourth set of systems covered in this synopsis is the combination of self-centering and energy-dissipating fuses. Case studies include PT-SCED braced frames, wedge devices, precast moment-resisting frames with PT strands in the connections, unbonded PT hybrid coupled wall subassemblages, and RC frames upgraded with SMA self-centering energy-dissipating braces.

Clifton et al. (2003) examined two new semi-rigid joints for moment resisting steel frames. Both the FBJs (Flange Bolted Joints) and SHJs (Sliding Hinge Joints) have been developed to undergo rotation during severe earthquakes, while suffering minimal structural damage. FBJs and SHJs are intended for low and high levels of design ductility demand, respectively.

The joints were designed and detailed to withstand the expected inelastic rotation associated with the design level ultimate limit state earthquake with negligible damage. However, the joints are also able to withstand a greater level of inelastic rotation, associated with more severe events.

Christopoulos et al (2008) examined buckling restrained and self-centering bracing systems. The purpose of this system was to eliminate damage to structural elements and minimize residual deformations by means of a brace member which can undergo large axial deformations. The experiment resulted in similar peak inter-story drifts in self-centering energy-dissipating frames (SCED) and buckling restrained braced (BRB) frames with less damage concentration and smaller residual lateral deformation in SCED system.

Braced fuse systems consist of an energy-dissipating mechanism (SCED bracing), structural steel member, pre-tensioned tendons, and a fuse element that can be replaced after yielding if it is bolted.

In this study, nonlinear dynamic analyses of building structures from 2 to 12 stories were performed to evaluate the performance of SCED braced frames with friction energy dissipation. Cyclic quasi-static and dynamic tests with simple shear beam to column connections show similar peak inter-story drifts in SCED and BRB braced frames, but less damage concentration and smaller residual lateral deformation occurred in the SCED system.