Feasibility of a nonlinear spectral approach for peak floor acceleration of multi-story bilinear hysteretic buildings

To protect the acceleration-sensitive non-structural components in a multi-story building, proper seismic design of them against peak floor acceleration (PFA) is needed. The PFA, therefore, should be estimated advance. efficiently estimate PFA buildings at inelastic stage, nonlinear modal combination approach provided this study. First, for single-story building (single-degree-of-freedom system), spectral ratio δ, defined as between and elastic amplitude, proposed to measure reductions PFA. A series time history analysis (THA) revealed that there dependable relationship strength reduction factor R, post-yield stiffness α, period T structure. scatter δ notably smaller than ductility demand, showing good feasibility δ-R-T-α predicting δ. Second, (multi-degree-of-freedom decoupled space, contribution each mode multiplied by account stage. Here can determined an appropriate relationship, while R α are via pushover analysis. modified contributions combined complete-quadratic (CQC) rule, forming CQC approach. PFAs some 2-, 5-, 8-story structures with different degrees nonlinearity computed THA Results demonstrate satisfactory accuracy latter. Notably, effects nonlinearities associated higher-order modes on well considered CQC, thus un-acceptable over-estimations which occurs conventional methods, avoided.