Seismic reliability implied by behavior?factor?based design

Force-based seismic design involves the reduction of elastic spectra by introducing a behavior factor, q. This approach is widespread in engineering practice; however, recent studies have shown that structures consistently designed at different sites will not share same level risk, which can be defined as annual rate structure failing to meet performance objective, despite actions having exceedance return period all sites. paper investigates whether definition site-specific q factors lead uniform risk across characterized varying levels hazard, based on pushover curves bare frame reinforced concrete buildings. These are used establish backbones equivalent single degree freedom systems with lateral resistance. fictitiously placed several Italian and their failure computed integrating fragility, assessed means incremental dynamic analysis, each site's hazard curve. By assuming an arbitrary threshold, for sites, corresponding strength leading said threshold determined factor back calculated. As expected, risk-targeted tend increase decreasing highly sensitive shape curve beyond period. Coupled fact low detailing gravity-load minimum code requirements, rather than actions, results suggest factor-based unsuitable warranting territorially safety, yet it may suitable setting upper-bound probability.