Session: SE-09-02 Advanced Seismic Evaluation and Code - 2

Paper Number: 107828

107828 - Study on Seismic Evaluation for Anchor Bolts in Circular Arrangement Using Elastic-Plastic Analysis 

In a seismic evaluation of equipment of nuclear power plants, anchor bolts for a component are required to resist against seismic conditions to support the component on the basement. Some components are directly fixed to the basement by anchor bolts, and the anchor bolts of a tank are arranged on the circumference. Anchor bolts are basically designed in elastic base, but actual material of them are confirmed to show plastic behavior by tensile testing. For rational evaluation for increasing seismic condition, an elastic-plastic analysis method has been studied to take account the condition that a few of the anchor bolts in circular arrangement become beyond elastic limit by seismic load. In the condition, even if yielding of a few of the anchor bolts is occurred, it is expected that its neighboring anchor bolts in a circular arrangement other than them could bear against the seismic loads and keep equipment support function of the anchor bolts because the anchor bolts could be counted elastic-plastic behavior. To evaluate this condition, seismic evaluations for anchor bolts in a circular arrangement have been performed by static pushover analyses using elastic-plastic analysis, in which the horizontal seismic load is gradually increased, and showed that the support function can be retained by the anchor bolts in a circular arrangement. In addition, static loading tests using a reduced scale model of a cylindrical storage tank have been performed to experimentally confirm that even if yielding of a few of the anchor bolts occurred due to the increase in load, the neighboring anchor bolts bore the load.

Presenting Author: Kensuke Terai Mitsubishi Heavy Industries, Ltd.

Presenting Author Biography: - Working for Mitsubishi Heavy Industries as a nuclear plant component designing engineer since 2011
- A member of Working Group on Vessels of JSME Subcommittee on Nuclear Power
- M.S. in Engineering from Tohoku University (Japan)

Authors:

Kensuke Terai Mitsubishi Heavy Industries, Ltd.
Masanori Amino MHI NS Engineering Co., Ltd.
Ichiro Tamura The Chugoku Electric Power Co., Inc.
Satoshi Iida The Chugoku Electric Power Co., Inc.