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

Author(s):  
Makoto Inaba ◽  
Masatoshi Ikeda ◽  
Nobuyuki Shimizu ◽  
Tetsuya Watanabe

After the Great Hyogoken-nanbu Earthquake, “Seismic Design Code for High Pressure Gas Facilities of Japan” was amended. This amended code requires two step seismic assessments, that is, evaluation of Level 1 Required Seismic Performance for Level 1 Earthquake and that of Level 2 Required Seismic Performance for Level 2 Earthquake. Seismic design of piping systems is newly involved in the scope of the code. For Level 2 Earthquake, possible ground displacement due to liquefaction is taken into account. When ground displacement occurs, foundations of structures settle, laterally move or incline as a conseqence, and a piping system supported by independent foundation structures suffers from relative displacements between supporting points, which may exceed several tens of centimeters. The evaluation method of Level 1 Required Seismic Performance is specified in the amended code and that of Level 2 Required Seismic Performance is proposed in the guideline. The former evaluation is based on elastic design and the latter on elasto-plastic design. The propriety of design criteria of piping systems against ground displacement was confirmed by large deformation tests. This paper introduces seismic design criteria of piping systems in the amended code and the evaluation method of Level 2 Required Seismic Performance proposed in the guideline, and also reports the results on the large deformation tests.

2004 ◽  
Vol 126 (1) ◽  
pp. 9-17 ◽  
Author(s):  
Makoto Inaba ◽  
Masatoshi Ikeda ◽  
Nobuyuki Shimizu

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.


2004 ◽  
Vol 126 (1) ◽  
pp. 2-8 ◽  
Author(s):  
Heki Shibata ◽  
Kohei Suzuki ◽  
Masatoshi Ikeda

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.


Author(s):  
Heki Shibata ◽  
Kohei Suzuki ◽  
Masatoshi Ikeda

The Seismic Design Code for High Pressure Gas Facilities was established in advance of other industrial fields in 1982. Only exception was that for nuclear power plants. In 1995, Hyogoken Nanbu earthquake brought approximately 6,000 deaths and more than 100,000 M$ loss or property in Kobe area, Japan. This unexpected serious event enforced us that industrial facilities should pay to special considerations of their damages including ground failure due to the liquefaction. Their strong ground motions brought serious damages to urban structures in the area. Thus, the Seismic Design Code of the High Pressure Gas Facilities were improved to include 2 step design assessments, that is, Level 1 earthquake (operating basisearthquake, the probable strong earthquake in the service life of the facilities), and Level 2 earthquake (safety shutdownearthquake, the possible strongest earthquake with extremely low probability of occurrence). For Level 2 earthquake, the ground failure by possible liquefaction shall be taken into account. In regard to Level 1 earthquake, the system must be remained safety without critical damage after the earthquake, in addition to no leakage of “gas”. In regard to Level 2 earthquake, the required seismic performance is that peventing systems must be remained without gas leakage, and stable. It means a certain non-elastic deformation without gas leakage may be allowed. The High Pressure Gas Safety Institute of Japan has set up the Seismic Safety Promotion Committee to modify their code in advance of other industries, and continue to investigate more reasonable seismic design practice for more than 5 years. Andthe final version of the guideline has been established for the design practices both in Level 1 and Level 2 earthquakes. This paper explains the activities of the committee, their new design concepts and scope of applications.


Author(s):  
Shinji Konosu

The High Pressure Institute of Japan has prescribed the Japanese FFS code, HPIS Z101 Level 1, which can evaluate a crack-like flaw without an extensive knowledge of fracture mechanics. Level 2 is currently being studied and will also be prescribed. In HPIS Z101 Level 2, a two-parameter method (FAD: Failure Assessment Diagram) will be adopted. This paper reveals that FACs dependent on the type of materials should be specified. Kr-Lr relations calculated from experimentally obtained Ramberg-Osgood constants of several steels are compared with the FACs of BS7910 Level 2A & API 579 Level 2, R6 Option 1 and ASME N494-3. It is found that the FAC of ferritic steel in ASME N494-3 is pertinent to carbon steels with a marked yield point plateau while the FAC of BS7910 Level 2A & API 579Level 2 is suitable for ferritic steels other than carbon steels such as 0.5Mo, 2.25Cr-1Mo and 2.25Cr-1Mo-0.25V steels. Further, cut-off values dependent on the strength of the material and the plasticity interaction factors for the FAC of carbon steels are proposed.


Author(s):  
Akihito Otani ◽  
Izumi Nakamura ◽  
Hajime Takada ◽  
Masaki Shiratori

Elbow is an essential element for three dimensionally arranged piping and it is actually used in most kinds of plants. Many great researches on the flexibility and stress intensity regarding elbow elements have been performed. Moreover, we can greatly benefit from the design code where elbow elements are specified. Our research group also started a research on ultimate strength of piping systems containing elbows in 1997 and we have performed several kinds of elbow element tests and shaking table tests. All experimental results have shown that the failure loads are far higher than those described by the design criteria. The authors have confirmed that the seismic design margin is extremely conservative. In this paper, the results of shaking table tests of piping, elbow element experiments and the stress calculation for those experiments based on design code are described, their results are compared with the seismic design criteria, and the margin is discussed. The authors point out the necessity of a new design code on the basis of the detail analysis and strain criteria in order to describe more appropriate and reasonable seismic design margin of the piping.


Author(s):  
Naoki Hirokawa ◽  
Mitsuru Yoneyama ◽  
Chikahiro Sato

In general, in evaluating large early release frequency (LERF) or containment failure frequency (CFF), level 2 PSA is separated from level 1PSA as described in NUREG-1150 [1]. A brief procedure of this evaluation is that: (1) the core damage frequencies (CDF) to be evaluated for level 1 PSA are grouped into plant damage states (PDSs) based on their accident progression attributes (similar timings to core damage and systems unavailability), (2) frequencies of PDSs are applied to the initial events of event trees (ETs) after the core damage (containment event trees (CETs)), and (3) CETs are developed and quantified. The above method rationally decreases the number of accident sequences to be evaluated in level 2 PSA. In this paper, CETs of internal events for operating state are connected to the end states of the core damage and performed a successive uncertainty analysis from initiating events to containment failures with taking into account for correlations between component failures for a BWR plant (BWR-5 / Mark-II). The rational and some conservative CFF evaluation method are also proposed because the calculation time and computer memory of the above detailed method was very heavy.


2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Moo-Won Hur ◽  
Tae-Won Park

The purpose of this study is to evaluate the applicability of seismic isolation devices for marine accidents under seismic loads. The lighthouse structure is a very important facility when the ship approaches the port. However, it is necessary to reinforce the structure to protect it from earthquake. This study presents isolation technology as a method to enhance the seismic performance of lighthouse structures built before seismic design criteria were established. This paper analyzed improvement of seismic performance in three cases of seismic isolation by applying the proposed method of isolation technology. In Case 1, the entire lighthouse structure is isolated, and in Case 2, only the lighthouse lens, the most important component of the lighthouse structure, has been isolated to assure constructability and economy. In Case 3, isolation effect was analyzed by comparing Case 1 and Case 2 with lighthouse structures.


2015 ◽  
Vol 31 (4) ◽  
pp. 2397-2417 ◽  
Author(s):  
Rakesh K. Goel

This investigation evaluated the current recommendations for plastic-hinge length and depth for piles in marine oil terminals considering nonlinear pile and soil behavior, as well as two seismic design levels: Level 1 and Level 2. It was found that the plastic-hinge length depends on seismic design level, whereas depth is independent of seismic design level. For pre-stressed concrete piles, the current plastic-hinge length recommendations were generally found to be adequate for seismic design Level 2, but provided much smaller plastic-hinge length for Level 1. For hollow-steel piles, the current plastic-hinge length recommendation was generally found to be adequate for sands, but provided much smaller plastic-hinge length for clays for both seismic design levels. Furthermore, the current recommendations lead to much shallower plastic-hinge depth than that found in this investigation.


Author(s):  
Yutaka Suzuki ◽  
Kunihiko Sato ◽  
Hirohide Iiizumi ◽  
Masakazu Hisatsune ◽  
Shigenobu Onishi

This paper provides a part of series of “Development of an Evaluation Method for Seismic Isolation Systems of Nuclear Power Facilities” [1]–[4]. This part describes the work schedule of this project and the summary of a seismic design for crossover piping system. Since the Southern Hyogo Prefecture Earthquake in 1995, a seismic isolated design has been widely adopted for Japanese typical buildings. The Japanese government accepted utilizing seismic isolation technology for nuclear power facilities with the 2006 revision of the “Regulatory Guide for Reviewing Seismic Design of Nuclear Power Reactor Facilities”. Under these backgrounds, the Japan national project with the participation of all electric power companies and reactor vendors has been started from 2008 to develop seismic isolation systems of nuclear power facilities under the support of the Ministry of Economy, Trade and Industry. In the design of seismic isolated plant, the crossover piping systems, such as Main Steam line and other lines related to the safety system have the important roles for overall plant safety. Therefore, the design of multiply supported piping systems between isolated and non-isolated buildings is one of the major key issues. This paper focuses on the seismic response analysis of Main Steam crossover piping between seismic isolated Reactor Building and non-isolated Turbine Building. Multiple input response spectra and time history analyses of the crossover piping have been performed and the structural integrity of piping and the validity of the multiple input analysis method have been verified based on comparisons with the results obtained by conventional response spectrum analysis using enveloped floor response spectrum.


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