Seismic design and behavior of self-centering energy dissipation braced steel frame

A self-centering energy dissipation (SCED) brace that utilized disc springs to provide self-centering capability and friction pads to dissipate energy was developed. Based on Bouc-Wen model and the working principle of SCED brace, a restoring force model is developed to describe the mechanical behavior of the brace. Comparisons between the cyclic loading tests and predicted results are conducted. Results show that the restoring force model can accurately predict both the energy dissipation and self-centering capabilities of SCED brace. A performance-based design method for frame structures with SCED braces is developed corresponding to the four-level seismic fortification objective, that is, no damage under minor and moderate earthquakes, replaceable or repairable under major earthquakes, and no collapse under mega earthquakes. A typical SCED braced steel frame was designed, and nonlinear time-history analysis was conducted to analyze the seismic performance and resilience of the braced frame. It is demonstrated that the SCED braced frame has superior resilience with small residual deformation under the moderate and major earthquakes due to the self-centering capability provided by the SCED brace. The collapse of the structure is also effectively avoided due to the stable energy dissipation and lateral stiffness provided by the SCED brace.