PREDICTORS OF SEISMIC DEMAND OF SMRF BUILDINGS CONSIDERING POST-ELASTIC MODE SHAPE

Predictors of seismic structural demands such as inter-story drift angles that are less time-consuming than nonlinear dynamic analysis can be useful for structural performance assessment and for design. Luco and Cornell proposed a simple predictor extending the idea of modal superposition of the first two modes with the SRSS rule and taking a first-mode inelastic spectral displacement into account. This predictor achieved quite an improvement from simply using the response of an elastic oscillator; however, it cannot capture well the large displacement due to local yielding. The possible improvement of Luco’s predictor is discussed in this paper considering a post-elastic mode.