25-08-2017, 09:32 PM
The inelastic (design) spectra characterizing a seismic hazard are generally obtained by the scaling-down of the elastic (design) spectra via a set of response modification factors. These factors depend on overstrength, ductility requirement, and structural redundancy of the system. The component of these factors, which accounts for the ductility demand ratio, is known as strength reduction factor (SRF). This factor represents the ratio of elastic strength demand to the inelastic strength demand of a single-degree-of-freedom oscillator with the inelastic deformations limited to a specified ductility demand ratio, and the variation of this factor with initial period of the oscillator is called as SRF spectrum. This study considers scaling of SRF spectrum in case of an elastoplastic oscilator with strength and stiffness degradation characteristics. Two models are considered: one depending directly on the characterization of source and site parameters and the other depending on the normalized design spectrum characterization of the seismic hazard. The first model is the sam