The Earthquake Engineering Online Archive

The design of steel energy-absorbing restrainers and their incorporation into nuclear power plants for enhanced safety (final technical report, vol 2): Development and testing of restraints for nuclear piping systems

Kelly, James M.; Skinner, Mark S.

UCB/EERC-80/21, Earthquake Engineering Research Center, University of California, Berkeley, 1980-06, 56 pages (530/D38/1980/v.2)

As an alternative to the current practice of restraining pipes within nuclear power plants, it has been proposed that restraints capable of dissipating energy in the piping system be adopted. The specific mode of energy dissipation focused upon in these studies is the plastic yielding of steels, utilizing relative movement between the pipe and the base of the restraint, a general mechanism proven to be reliable in several allied studies. To include application and design flexibility in such restraint systems, it is desirable that three different models, incorporating one, two, and three orthogonal directions of translation to dissipate energy while the other directions remain fixed, be developed. To this end, the authors have conceptualized three such devices. This report discusses the testing of examples of the first two of these energy-absorbing devices, the results of this testing, and the conclusions drawn. The study concentrates upon the specific relevant performance characteristics of hysteretic behavior and degradation with use. The testing consisted of repetitive continuous loadings well into the plastic ranges of the devices, in a sinusoidal or random displacement controlled mode. Overall, the devices proved to have substantial capacity to absorb energy and the testing verifies their utility as reliable energy-dissipating elements for piping systems. However, the testing also shows that one of the devices yielded inadequate performance in one mode of application.

Available online: http://nisee.berkeley.edu/documents/EERC/EERC-80-21.pdf (4 MB)