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Ichihara, Yoshitaka*; Nakamura, Naohiro*; Nabeshima, Kunihiko*; Choi, B.; Nishida, Akemi
Kozo Kogaku Rombunshu, B, 68B, p.271 - 283, 2022/04
This paper aims to evaluate the applicability of the equivalent linear analysis method for reinforced concrete, which uses frequency-independent hysteretic damping, to the seismic design of reactor building of the nuclear power plant. To achieve this, we performed three-dimensional FEM analyses of the soil-structure interaction system, focusing on the nonlinear and equivalent linear seismic behavior of a reactor building under an ideal soil condition. From these results, the method of equivalent analysis showed generally good correspondence with the method of the nonlinear analysis, confirming the effectiveness. Moreover, the method tended to lower the structural stiffness compared to the nonlinear analysis model. Therefore, in the evaluation of the maximum shear strain, we consider that the results were more likely to be higher than the results of nonlinear analysis.
Fukasawa, Tsuyoshi*; Somaki, Takahiro*; Miyagawa, Takayuki*; Uchita, Masato*; Yamamoto, Tomohiko; Ishizuka, Futoshi*; Suzuno, Tetsuji*; Okamura, Shigeki*; Fujita, Satoshi*
Kozo Kogaku Rombunshu, B, 68B, p.462 - 475, 2022/04
Ota, Yoshimi*; Nishida, Akemi; Tsubota, Haruji
Kozo Kogaku Rombunshu, A (CD-ROM), 63A, p.1132 - 1140, 2017/03
Many empirical formulas have been proposed for evaluating the local damage to reinforced concrete structures caused by rigid missile impact. Most of these formulas have been derived based on impact tests perpendicular to target structures and up to now few impact tests oblique to target structures has been carried out. Therefore, the purpose of this study is to propose a new formula for evaluating the local damage caused by oblique impact based on past experimental results and simulation results. In this paper, a new formula is derived by modifying a past empirical formula of normal impact and the conformity of the formula to the results of past oblique impact tests is discussed.
Choi, B.; Nishida, Akemi; Nakajima, Norihiro
Kozo Kogaku Rombunshu, B, 63B, p.325 - 333, 2017/03
The Japan Atomic Energy Agency promotes research and development of three-dimensional vibration simulation technologies for nuclear facilities. In this paper, we report a seismic response analysis of the Tohoku Pacific Coast Earthquake using three-dimensional models of the High-Temperature Engineering Test Reactor (HTTR) building. We conducted a sensitivity study using input parameters with uncertainty. Furthermore, we examined the variation of the seismic response results against the input parameters.
Miyazaki, Akemi
Kozo Kogaku Rombunshu, B, 52B, p.119 - 124, 2006/03
Since it is generally difficult to predict the occurrence of natural disasters such as earthquakes, a performance management system that always maintains the safety and functionalities of structures is required, especially for critical ones like nuclear power plants. In order to realize such a system, it is becoming important to carry out modeling procedures and analyses in detail to better understand the real phenomena. Such details are important in understanding the phenomena occurring in frame structures such as piping systems which are considered to be one of the vulnerable parts in nuclear power plants. The aim of our research is to solve the dynamic behavior of piping systems in nuclear power plants which are complicated assemblages of parts. The spectral element method is adopted in this work and the formulation considering a shear deformation of a frame element is described. The Timoshenko beam theory is introduced for the purpose of this formulation. The validity of the presented element will be shown through comparisons made with the conventional beam.
