Seismic risk evaluation of pipeline supporting chevron steel concentrically braced frames designed according to general steel design requirements

Pipe racks transporting toxic and chemical materials are typically considered as a post-earthquake facility that should maintain their functionality before, during and after strong ground motion. Chevron concentrically braced frames (CBFs) are generally employed as their seismic force-resisting systems in the longitudinal direction of pipelines. Some of seismic design codes allow for pipeline-supporting chevron CBFs to be designed according to general regulations for typical steel structures without specific seismic considerations including unbalanced forces. This study aims to carried out the robust and systematic seismic risk evaluation of such chevron CBFs. To do this, archetype chevron CBFs had been first selected, and nonlinear time history analyses were then performed to investigate their seismic responses. Also, incremental dynamic analyses (IDAs) were performed to evaluate their seismic risk against the dual limit states, the structural collapse and the leakage of pipelines. The analysis results demonstrate that the archetype CBFs designed according to only general requirements do not satisfy the acceptance criteria for the dual limit states.