In this paper, the effect of floor response spectra (FRS) and seismic anchor movement (SAM) on the seismic stresses in the piping system is studied through a combination of finite element analysis (FEA) and the Taguchi Method. Class 3 piping systems according to ASME B&PV code Section III Subsection ND with different natural frequencies are analyzed in this study. Taguchi method is applied to create an orthogonal array to show the variability of FRS and SAM, which is taken as the ±20% variation over its nominal value. Based on the Taguchi orthogonal array, finite element simulations are carried out to obtain the seismic code stress in each piping system. From the Taguchi signal-to-noise (S/N) ratio analysis and the analysis of variance (ANOVA) of the seismic code stress results, the effect of FRS and SAM on the resultant seismic stress is given and expressed as a percentage. The study shows that the FRS is dominating the seismic stress for the piping system with low natural frequency (i.e., flexible system) while SAM is dominating the seismic stress for the piping system with high natural frequency (i.e., rigid system), for the piping system with a medium natural frequency, both FRS and SAM contribute to the seismic stress and the percentage of contribution of each parameter varies with the level of the system natural frequency. The results of this study also show that if the piping system is designed either too rigid or too flexible for the same layout, it will result in high resultant (primary plus secondary) seismic stress.

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