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Dr. Yuqing Liu, Bechtel Global Functional Manager of Pipe Stress and Vibration Engineering, points out in a 2022 youtube video presentation that "At the end of the day, dynamic (loads) cause more damage to your plants than static (loads)." In that same video Dr. Liu shared results of a case study involving waterhammer dynamic loads where "We saved the client, we saved the project millions of dollars by using time history analysis (instead of DLFs). We also saved the project's schedule" since it would have taken months longer to redesign and fabricate piping, structure and foundation had they relied on results from commonly used DLF values, which were wildly overconservative as compared to results from time history dynamic analysis (10X higher support load).
Similarly, in seismic zones, design results using a static seismic acceleration load approach are not usually compared with results using response spectra or time history dynamic analysis. However, unlike the use of DLF in waterhammer and slug flow applications, at least the static seismic loads are usually based on codified values which have some justification. Time history analysis would consider a more realistic distribution of seismic loads because mass is typically not evenly distributed in a piperack structure, particularly rack structures supporting heavy equipment with piping. Seismic ground motion acceleration records are becoming increasingly more available through organizations like PEER. CSiPlant can easily import these ground motion time vs acceleration records for nonlinear time history analysis.
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