| Most current seismic design codes are the elastic design methods which are based on the force or strength. Ander the seldomly occurred earthquake the structure was avoided appearing weakness floors by checking the maximum interstory deflection,it's couldn't guarantee the structure emerging the ideal failure mode in the elastoplasticity stage. The constructions that designed and built according to the present seismic design idea aims was subjected to the strong earthquake exceeding design standard, ensured the life safety of the public, but the destroy of the earthquake caused a great economic waste. Based on above acquaintance, a new seismic idea was born: the idea of performance-based seismic design.Yield Point Spectra is a new constant ductility response spectrum with displacement-acceleration format. For design, YPS can be used to obtain the minimum lateral strength required to limit peak roof displacement and ductility to arbitrary values for design earthquakes,.YPS method is effective, simple and clear.A total of 7 ground motion records were selected to construct the YPS appropriate for seismic design and propose the capacity design approach of performance–basing that the base shear of K- eccentrically braced steel frame was determined based on the YPS,.The seismic behavior of ten story three span,twelve story three span ,fifteen story three span K-EBF was designed and evaluated based on the Pushover method and nonlinear time history method. The results showed that the yield displacement of the example was fundamentally stable, and could satisfy the deformation requirement of seismic code under occasional and rare earthquake level. The K-EBF structure took on the ideal progressively plastic mechanism. The reliablity and accuracy of this new design method were proved. |
