A NOVEL PERFORMANCE-BASED SEISMIC DESIGN METHOD AND ITS APPLICATION IN BRB STEEL FRAMES

A performance-based seismic design method for buckling-restrained braced steel frames is proposed. Its three performance targets are in terms of the peak interstory drift ratio, the peak floor acceleration and the residual interstory drift ratio respectively, and it aims to ensure the seismic safety of structural and nonstructural components. Through the parametric analyses of equivalent single-degree-of-freedom (SDOF) systems, the relationships between the seismic response indexes and the fundamental period, as well as the strength reduction factor, are built. Then the SDOF-based results are incorporated into the multi-degree-of-freedom systems, and the design method is developed. To demonstrate and validate the method, this study conducts seismic design for a six-story benchmark buckling-restrained braced frame (BRBF) which are subjected to a suite of earthquake records. The performance evaluation indicates that the properly designed BRBF meets three performance targets at the same time. This study also sheds light on the seismic design of other types of buildings.