Seismic performance-based assessment of a RC pipe rack accounting for dynamic interaction

Abstract

In contrast with common buildings, the limit-state assessment has not been applied to pipe-rack – piping systems yet, albeit the seismic vulnerability of critical pipes is rather high. The current engineering practice may design pipe rack – piping systems in a risk-inconsistent way due to the conservative acceptance criteria of seismic codes that keep pipes in the elastic range. Additionally, the response of pipes could become complex when considering differential displacements between internal supports, pipe edges and adjacent structures, which static methods may not describe efficiently. The design of a typical RC pipe rack – piping system in a code-consistent way resulted in two main outcomes. First, the piping required the increase of structural members cross-section, and secondly, the differential displacement was the main reason of pipe failure both in the longitudinal (unrestrained) as well as transverse direction. Finally, the performance-based assessment of this type of system demonstrated that the spectral acceleration is mildly more efficient and sufficient intensity measure than ground ones to describe the damage on piping. The observed mean annual frequency of exceedance was 57% smaller than the targeted value for the pipes, whereas the difference was considerably higher for the pipe rack. This outcome corroborated the conservativeness of codes and the risk-inconsistency between the structural and non-structural members.