Analytical study for low ground contact ratio of buildings due to the basemat uplift using a three-dimensional finite element model

Choi, B.; Nishida, Akemi; Shiomi, Tadahiko; Kawata, Manabu; Li, Y.

Proceedings of 29th International Conference on Nuclear Engineering (ICONE 29) (Internet), 6 Pages, 2022/08

In the seismic evaluation of nuclear facility buildings, basemat uplift-the phenomenon during which the bottom of the basemat of a building partially rises from the ground owing to overturning moments during earthquakes-is a very important aspect because it affects not only structural strength and integrity, but also the response of equipment installed in the building. However, there are not enough analytical studies on the behavior of buildings with a low ground contact ratio due to basemat uplift during earthquakes. In this study, we conducted a simulation using a three-dimensional finite element model from past experiments on basemat uplift; further, we confirmed the validity of this approach. In order to confirm the difference in the analytical results depending on the analysis code, the simulation was performed under the same analytical conditions using the three analysis codes, which are E-FrontISTR, FINAS/STAR and TDAPIII, and the obtained analysis results were compared. Accordingly, we investigated the influence of the difference in adhesion on the structural response at low ground contact ratio. In addition, we confirmed the effects of significant analysis parameters on the structural response via sensitivity analysis. In this paper, we report the analytical results and insights obtained from these investigations.

Standard guideline for the seismic response analysis method using 3D finite element model of reactor buildings (Contract research)

Choi, B.; Nishida, Akemi; Kawata, Manabu; Shiomi, Tadahiko; Li, Y.

JAEA-Research 2021-017, 174 Pages, 2022/03

JAEA-Research-2021-017.pdf:9.33MB

Standard methods such as lumped mass models have been used in the assessment of seismic safety and the design of building structures in nuclear facilities. Recent advances in computer capabilities allow the use of three-dimensional finite element (3D FE) models to account for the 3D behavior of buildings, material nonlinearity, and the nonlinear soil-structure interaction effect. Since the 3D FE model enables more complex and high-level treatment than ever before, it is necessary to ensure the reliability of the analytical results generated by the 3D FE model. Guidelines for assuring the dependability of modeling techniques and the treatment of nonlinear aspects of material properties have already been created and technical certifications have been awarded in domains other than nuclear engineering. The International Atomic Energy Agency performed an international benchmark study in nuclear engineering. Multiple organizations reported on the results of seismic response studies using the 3D FE model based on recordings from the Niigata-ken Chuetsuoki Earthquake in 2007. The variation in their analytical results was significant, indicating an urgent need to improve the reliability of the analytical results by standardization of the analytical methods using 3D FE models. Additionally, it has been pointed out that it is necessary to understand the 3D behavior in the seismic fragility assessment of buildings and equipment, which requires evaluating the realistic nonlinear behavior of building facilities when assessing their seismic fragility. In view of these considerations, a standard guideline for the seismic response analysis method using a 3D FE model was produced by incorporating the latest knowledge and findings in this area. The purpose of the guideline is to improve the reliability of the seismic response analysis method using 3D FE model of reactor buildings. The guideline consists of a main body, commentaries, and appendixes; it also provides standard procedures

Outline of guideline for seismic response analysis method using 3D finite element model of reactor building

Choi, B.; Nishida, Akemi; Shiomi, Tadahiko; Kawata, Manabu; Li, Y.

Proceedings of 28th International Conference on Nuclear Engineering (ICONE 28) (Internet), 7 Pages, 2021/08

https://doi.org/10.1115/ICONE28-61786

In the seismic safety assessment of building structures in nuclear facilities, lumped mass models are conventionally used. However, they cannot possess the required high-accuracy evaluation of nuclear facilities, such as the local response at the equipment location in a reactor building. In this point of view, a seismic response analysis method using a three-dimensional finite element (3D FE) model is indispensable. Although, it has been reported that the analysis results obtained using 3D FE models vary greatly depending on the experience and knowledge of analysts, the quality of analysis results should be insured by developing a standard analysis method. In the Japan Atomic Energy Agency, we have developed a guideline for seismic response analysis methods that adopt 3D FE models of reactor buildings. The guideline consists of a main body, commentary, and several supplements; it also includes procedures, recommendations, points of attention, and a technical basis for conducting seismic response analysis using 3D FE models of reactor buildings. In this paper, the outline of the guideline and analysis examples based on the guideline are presented.

Large scale earthquake response analysis of nuclear test reactor utilizing assembling method of 3 dimensional CAD models

Nishida, Akemi; Shiomi, Tadahiko*

Nihon Kenchiku Gakkai 2007-Nendo Taikai Gakujutsu Koen Kogaishu, p.1071 - 1072, 2007/08

Additional reliability is expected for maintaining the safety of infrastructures like nuclear plants. We have focused on the construction an analysis system termed the "three-dimensional virtual plant vibration simulator," which is a numerical simulation system for a nuclear plant that considers the interconnection of components, buildings, and their foundations under real operating conditions. In this paper, an application example of the seismic response analysis of a nuclear building is shown. Detailed stress evaluation becomes possible by using the building response as the input for the component supports. The construction of a system that enables the generation of the mesh data of each structural part with a different mesh precision is reported, and by including a technology that can address the problems between the parts of an assembly structure, it is possible to reduce the loads in the complicated modeling work.

Standardization of a three-dimensional modeling method for a reactor building

Nishida, Akemi; Choi, B.; Shiomi, Tadahiko; Li, Y.

no journal, , 

With the development of computational methods in engineering and advanced computer technologies, three-dimensional modeling based on actual shapes are possible in structural analysis; in recent years, this method has been utilized in various applications, such as stress and response analyses. Three-dimensional models are also being used for reactor buildings to support earthquake resistance evaluations, among others. However, the quality of the three-dimensional model depends on the analyst, and confirming the validity of the obtained result is a challenge because of the difficulty of performing full scale experiments for the reactor building. Based on these situations, JAEA has started the R&D to standardize the method of constructing the three-dimensional model of the reactor building. The outline of this standardization approach is shown in this presentation.

Study for low ground contact ratio of buildings due to the basemat uplift using a three-dimensional finite element analysis, 1; Outline and verification of basemat uplift analysis function

Choi, B.; Nishida, Akemi; Kawata, Manabu; Shiomi, Tadahiko; Ota, Akira*; Sonobe, Hideaki*; Ino, Susumu*

no journal, , 

no abstracts in English

Study for low ground contact ratio of buildings due to the basemat uplift using a three-dimensional finite element analysis, 3; Reproduction Analysis of Experiment No.2

Sonobe, Hideaki*; Ota, Akira*; Ino, Susumu*; Choi, B.; Nishida, Akemi; Kawata, Manabu; Shiomi, Tadahiko

no journal, , 

no abstracts in English

Standard guideline for the seismic response analysis method using three-dimensional detailed model of reactor buildings

Choi, B.; Nishida, Akemi; Shiomi, Tadahiko; Kawata, Manabu; Li, Y.

no journal, , 

no abstracts in English