An Advanced Computational Method for Nonlinear Behavior of Piping Systems Subject to Earthquake Load

2004

Journal of JAEE

Self Cite

Seismic design of high-pressure gas facilities had been carried out in accordance with MITI notification 515 "Seismic Design Code" established in 1981. The Great Hyogoken-nanbu Earthquake occurred in 1995. Some facilities and piping systems were damaged due to ground displacement (settlement and/or lateral movement) induced by liquefaction. Having learned from the experiences, the seismic design code was amended in 1997. This paper introduces requirements in the new seismic design code and the evaluation method of Required Seismic Performance proposed.

Section: Develpment Of Design Methods For Piping Systems For L2-rspmentioning

confidence: 99%

Development of Seismic Design Code for High Pressure Gas Facilities

2004

Journal of JAEE

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Development of Seismic Design Code for High Pressure Gas Facilities in Japan

Shibata

Suzuki

Journal of Pressure Vessel Technology

2004

Self Cite

The Seismic Design Code for High Pressure Gas Facilities was established in 1982 in advance of those in other industrial fields, the only exception being that for nuclear power plants. In 1995, Hyogoken Nanbu earthquake caused approximately 6000 deaths and more than $1 billion (US) loss of property in the Kobe area, Japan. This unexpected disaster underlined the idea that industrial facilities should pay special consideration to damages including ground failure due to the liquefaction. Strong ground motions caused serious damage to urban structures in the area. Thus, the Seismic Design Code of the High Pressure Gas Facilities were improved to include two-step design assessments, that is, for Level 1 earthquakes (operating basis earthquake: a probable strong earthquake during the service life of the facilities), and Level 2 earthquakes (safety shutdown earthquake: a possible strongest earthquake with extremely low probability of occurrence). For Level 2 earthquakes, ground failure by possible liquefaction will be taken into account. For a Level 1 earthquake, the required seismic performance is that the system must remain safe without critical damage after the earthquake, including no gas leakage. For a Level 2 earthquake, the required seismic performance is that the system must remain safe without gas leakage. This means a certain non-elastic deformation without gas leakage may be allowed. The High Pressure Gas Safety Institute of Japan set up the Seismic Safety Promotion Committee to modify their code, in advance of other industries, and has continued to investigate more effective seismic design practices for more than 5 years. The final version of the guidelines has established design practices for the both Level 1 and Level 2 earthquakes. In this paper, the activities of the committee, their new design concepts and scope of applications are explained.

New Seismic Design Criteria of Piping Systems in High-Pressure Gas Facilities

Inaba

Journal of Pressure Vessel Technology

Sato

2004

After the Great Hyogoken-nanbu Earthquake (1995), the Seismic Design Code for High-Pressure Gas Facilities of Japan was amended. This amended code requires two-step seismic assessments, that is, the evaluation of the Level 1 Required Seismic Performance for Level 1 earthquakes and that of the Level 2 Required Seismic Performance for Level 2 earthquakes. Seismic design of piping systems is newly included within the scope of the code. For Level 2 earthquakes, possible ground displacement due to liquefaction is taken into account. The evaluation method of the Level 1 Required Seismic Performance is specified in the amended code and that of the Level 2 Required Seismic Performance is proposed in the guideline. The evaluation of the former is based on elastic design and that of the latter on elastoplastic design. The propriety of the design criteria of piping systems with respect to ground displacement was confirmed by large deformation tests. In this paper, seismic design criteria of piping systems in the amended code and the evaluation method of the Level 2 Required Seismic Performance proposed in the guideline are introduced, and the results of the large deformation tests are reported.