Stochastic damage-reduction spectrum for seismic design of buildings with structural fuses

Summary Stochastic damage-reduction spectrum is proposed to design the buildings with metallic hysteretic dampers as structural fuses by considering the randomness of seismic loads. Firstly, the structure is separated into two parts: the main part with structural function and the part of structural fuses that is used to dissipate seismic energy. Then a dimensionless single-degree-of-freedom (SDOF) system with trilinear restoring force is obtained via structural pushover analysis. The stochastic damage-reduction spectrum is derived from the SDOF system by utilizing stochastic synthetic ground motions based on a set of far-field earthquake records. Parameter set of the stochastic damage-reduction spectrum is studied with the information of structural reliability of the SDOF system. Efficiency of the stochastic damage-reduction spectrum is confirmed in an example of seismic design of nine-story planar steel frame with the buckling restrained braces as the structural fuses. An extreme case of seismic load is also considered to test designs from different damage-reduction spectrum. The seismic design is thus with higher rate of energy absorption by using the stochastic damage-reduction spectrum.