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FROM:
Gert j. Dijkstra, Benjamin Francis, Hildo van der Heden and Arnold M. Gresnigt,
“Industrial steel pipe system under seismic loading: A comparison of European and American design codes”, COMPDYN 2011, 3rd ECCOMAS Computational Methods in Structural Dynamics and Earthquake Engineering, edited by M. Papadrakakis, M. Fragiadakis and V. Plevris, Corfu, Greece, 25-28 May 2011
ABSTRACT: In the framework of the INDUSE project, which aims at innovative design methodologies for the seismic design of industrial equipment and piping systems, case studies have been carried out, performing static and dynamic seismic analyses for two existing steel pipeline systems including steel supporting structures, situated in an area of moderate seismic activity:
a) A long aboveground 10" ammonia transmission line situated on sleepers with a vertical expansion loop and ending with a fixed point. The system may be typical for long distance above ground pipelines and for pipelines on jetties.
b) A 20" gas transmission pipeline at the interface of a buried pipeline section and an above ground piping section, including a branch connection, a vertical spring support structure and a fixed point, e.g. a tank nozzle. This system is typical for many plant piping systems.
The calculations were made using commercially available software. Both simplified static equivalent (‘uniform load method’) calculations as well as dynamic calculations were made in accordance with American (ASCE-7) and European (EN1998 and EN13480) earthquake design standards to identify differences in approach, differences in resulting seismic response spectra and differences in calculated results. The dynamic and static calculations were made with Caesar II software.
The results of the calculations are presented. Conclusions and recommendations are given with respect to:
- The differences between existing earthquake design codes.
- The validity of the use of the "static equivalent (uniform load) method".
- The need to include guidelines for design and modeling in the next revisions of existing seismic design standards for (above ground) industrial piping systems.
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