139 Seismic response analysis of seismic isolation system for steel pipe pile foundation with sliding bearing

This paper, which is part of the series entitled “Development of an Evaluation Method for Seismic Isolation Systems of Nuclear Power Facilities”, shows the linear seismic response of crossover piping installed in a seismically isolated plant. The crossover piping, supported by both isolated and non-isolated buildings, deforms with large relative displacement between the two buildings and the seismic response of the crossover piping is caused by two different seismic excitations from the buildings. A flexible and robust structure is needed for the high-pressure crossover piping. In this study, shaking tests on a 1/10 scale piping model and FEM analyses were performed to investigate the seismic response of the crossover piping which was excited and deformed by two different seismic motions under isolated and non-isolated conditions. Specifically, as linear response analysis of the crossover piping, modal time-history analysis and response spectrum analysis with multiple excitations were carried out and the applicability of the analyses was confirmed. Moreover, the seismic response of actual crossover piping was estimated and the feasibility was evaluated.

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Mechanism of Localized Corrosion of Steel Pipe Pile Foundation for Offshore Wind Turbines and Corrosive Action

The Open Civil Engineering Journal ◽

10.2174/1874149501610010685 ◽

2016 ◽

Vol 10 (1) ◽

pp. 685-694

Author(s):

Kui Wang ◽

Zhanqiang Li ◽

Mingjie Zhao

Keyword(s):

Wind Turbine ◽

Ultimate Strength ◽

Pile Foundation ◽

Local Corrosion ◽

Steel Pipe ◽

Corrosion Mechanism ◽

General Corrosion ◽

Splash Zone ◽

Pipe Pile ◽

Steel Pipe Pile

The wind turbine foundation serves as a permanent construction in the harsh marine corrosive environment, its anti-corrosion design is essential to the safe use of the wind turbine structure. At present, there is a significant controversy over the local corrosion mechanism (such as pitting corrosion, and crevice corrosion) and its diffusion mechanism in the academic circle. In the paper, the Faraday electrochemistry formula was used to compute the local corrosion degree of the steel pipe pile for the wind turbine and obtain the general corrosion equivalent. The local corrosion effect of the offshore steel pipe pile for the wind turbine was converted into homogeneous corrosion thickness loss of certain length, and then the ultimate strength of the offshore steel pipe pile foundation for the wind turbine was analyzed under the conditions of local corrosion. The result indicates that the maximum ultimate strength reductionof the steel pipe pile for the wind turbine induced by the local corrosion in the splash zone is 80.8% of the non-corrosive ultimate strength. The maximum ultimate strength reduction of the steel pipe pile for the wind turbine induced by the local corrosion in the continuous immersion zone is 63% of the non-corrosive ultimate strength. Once the local corrosion rate in the splash zone exceeds 10%, the ultimate strength of the steel pipe pile for the wind turbine will exhibit a negative exponential decrease. The local corrosion in the continuous immersion zone has a huge effect on its ultimate strength. There are no significant signs of the structural strength loss. The areas prone to local corrosion should be prioritized in anti-corrosion design of the steel pipe pile for the wind turbine.

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Analysis of Vibration Response to Sweep Waves on House Model Structures with Steel Pipe Pile Foundation Equipped with/without Hemispherical Sliding Bearings

The Proceedings of Conference of Tohoku Branch ◽

10.1299/jsmeth.2021.56.151_paper ◽

2021 ◽

Vol 2021.56 (0) ◽

pp. 151_paper

Author(s):

Yuhki MIYAMOTO ◽

Hiroyuki ISHII ◽

Kenta KITAGAWA ◽

Kosuke ITO

Keyword(s):

Pile Foundation ◽

Vibration Response ◽

Steel Pipe ◽

Sliding Bearings ◽

Pipe Pile ◽

Model Structures ◽

Steel Pipe Pile

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Research and Development of Three-Dimensional Isolation System for Sodium-Cooled Fast Reactor: Part 1 — Proposal of Analytical Models Based on Loading Tests

Volume 8: Seismic Engineering ◽

10.1115/pvp2018-84532 ◽

2018 ◽

Cited By ~ 1

Author(s):

Tsuyoshi Fukasawa ◽

Shigeki Okamura ◽

Takahiro Somaki ◽

Takayuki Miyagawa ◽

Masato Uchita ◽

...

Keyword(s):

Seismic Response ◽

Analytical Model ◽

Three Dimensional ◽

Analytical Models ◽

Response Analysis ◽

Seismic Response Analysis ◽

Natural Period ◽

Isolation System ◽

Loading Tests ◽

Rubber Bearings

This paper describes that the analytical model for the three-dimensional isolation system [1], which consists of thick rubber bearings, disc springs and oil dampers, is created through loading tests. The new-type analytical models of each element are proposed to improve the prediction accuracy of the seismic response analysis. The concept of the three-dimensional isolation system has been proposed to ensure the structural integrity for large reactor vessels. The primary specifications of the three-dimensional isolation system are a horizontal natural period of 3.4 s and a vertical natural period of 0.33 s. The investigations of horizontal isolation performances have been conducted for the various types of isolation devices, beginning with rubber bearings, whereas the previous studies focused on the vertical isolation performances are only a few. Hence, isolation characteristics, such as restoring force and damping force, should be clarified by loading tests using vertical seismic isolation elements, and analytical model to assess the seismic response should be identified on the basis of the loading test results. This paper presents a new analytical model with providing of the differential equations to improve the prediction accuracy and demonstrates the seismic performance, including beyond-design-basis ground motion, for the three-dimensional isolation system by the seismic response analysis.

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SEISMIC RESPONSE ANALYSIS OF RC PILE FOUNDATION-SOIL COUPLED SYSTEM USING 3D NONLINEAR FINITE ELEMENT METHOD

Doboku Gakkai Ronbunshuu A ◽

10.2208/jsceja.64.192 ◽

2008 ◽

Vol 64 (2) ◽

pp. 192-207

Author(s):

Takeshi MAKI ◽

Satoshi TSUCHIYA ◽

Tadatomo WATANABE ◽

Koichi MAEKAWA

Keyword(s):

Finite Element Method ◽

Finite Element ◽

Seismic Response ◽

Pile Foundation ◽

Coupled System ◽

Nonlinear Finite Element ◽

Response Analysis ◽

Nonlinear Finite Element Method ◽

Seismic Response Analysis ◽

Foundation Soil

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Seismic Fragility Evaluation of Interface Pipes in Seismically Isolated NPPs by Using Scale Model Test

Volume 8: Seismic Engineering ◽

10.1115/pvp2015-45042 ◽

2015 ◽

Author(s):

Daegi Hahm ◽

Min-Kyu Kim ◽

In-Kil Choi ◽

Bub Gyu Jeon ◽

Hyoung Suk Choi ◽

...

Keyword(s):

Seismic Response ◽

Nuclear Power ◽

Seismic Isolation ◽

Response Analysis ◽

Seismic Events ◽

Piping System ◽

Seismic Response Analysis ◽

Secondary Systems ◽

Inelastic Seismic Response ◽

Isolation Device

Seismic isolation system can be an effective alternative to protect the NPPs (Nuclear Power Plants) against to the strong seismic events. Therefore, some research activities to adopt the seismic isolation concept to the design of the next generation NPPs have been progressed for last few years in Korea. Nuclear structures, secondary systems and components must remain undamaged during and after the SSE (Safe Shutdown Earthquake) event. The seismic events will cause the high seismic response in the stiff structural systems and extremely high demands of deformation on the safety-related secondary systems like piping components. If seismic isolation devices are installed in nuclear power plant for seismic stability, safety against seismic load of power plant may be improved. But in some equipment, seismic risk may increase because displacement may become greater than before installation of seismic isolation device. Therefore, it is necessary to select the equipment in which seismic risk increases due to increase in displacement by the installation of seismic isolation device, and perform a research on seismic performance evaluation of equipment. In this study, one of the typical Korean NPPs assuming the application of seismic isolation devices, and one of the interface piping systems which introduced this NPP was used for seismic analysis. The numerical models include representations of seismic isolation devices. In order to validation of numerical piping system model and defining failure mode & limit states, quasi-static loading tests were conducted on the scale-modeled piping components before the analysis procedures. The fragility analysis was performed by using results of inelastic seismic response analysis. Inelastic seismic response analysis was carried out by using shell finite element model of piping system considering internal pressure. The implicit method was used for the direct integration time history analysis. Generally, PGA (Peak Ground Acceleration) was used for seismic intensity of fragility curve. However, in the case of the displacement sensitive system, lateral displacement could be an useful alternative measure for estimation of probability of failure. Thus in this paper, fragility curves were plotted based on maximum relative displacement.

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