A refined design spectrum model for regions of lower seismicity

Abstract

This paper presents a refined site classification scheme and a design spectrum (DS) model for different site conditions, with site natural period as the key classification parameter. The refined model has a particular emphasis on the phenomenon of resonant-like amplification behaviour in soil sites, which have not been explicitly considered in any existing code models. The need to address the effects of soil resonance and increased displacement demand is particularly justified in regions of lower seismicity, where structures are typically of limited ductility with low energy dissipation capability. Significantly, the mitigating effects of a very flexible soil site resulting in reduction in t..