Abstract
This paper proposes a performance based design diagram to estimate cumulative responses of bilinear hysteretic systems using triple elastic response spectra. The design diagram is based on a concept of separated variables of an energy spectrum for the target seismic ground motion; that is, energy spectrum Seq(T) can be expressed by the product of an elastic spectrum S(T) and empirical formulas including the parameters of viscous damping ratio h, ductility factor μd and bilinear stiffness factor pd,. This paper proposes modified energy spectrum VE,40/ newly defined, in addition of pseudo velocity spectrum pSv,40 and velocity spectrum Sv,40 utilized in the previous diagrams. The paper shows that the cumulative responses estimated by the proposed diagram are accurately agreed to the results computed by non-linear time history analyses of 239,400 cases.
