Shaking Table Study of the Three-Dimensional Isolation of a Cylindrical Reticulated Shell

Gui-bo Nie,Chenxiao Zhang,Zhi-yong Wang,Yu-jie Shi 한국강구조학회 2022 International Journal of Steel Structures Vol.22 No.2

A set of shaking table tests were conducted to investigate the dynamic response characteristics of a single-layer cylindrical reticulated shell (SLCRS) with three-dimensional column-top seismic isolation. The infl uence of infi lled wall on the seismic and isolation performance of the structure was investigated. The dynamic response characteristics of structures with and without seismic isolation were compared to investigate the eff ects of seismic isolation. The dynamic responses of lower-frame models with and without an infi lled wall were also compared to investigate the eff ects of the infi lled wall on the seismic isolation. Results show that the three-dimensional column-top seismic isolation improved the seismic safety of infi lled wall. At the same time, the three-dimensional column-top isolation bearing can signifi cantly reduce the acceleration and stress of the structure. The excellent isolation performance of the three-dimensional isolation bearing promises outstanding application prospects for this isolation bearing in highly seismic areas. In addition, under a small earthquake, the acceleration of the second fl oor with the isolation bearing was unfavorably magnifi ed. Therefore, the seismic performance of the acceleration-sensitive nonstructural components should be improved when the three-dimensional column-top seismic isolation is applied in the areas of low seismicity. The test data and conclusions obtained in the present study can provide theoretical and technical support for the actual engineering application of such three-dimensional seismic isolation bearings.

A Seismic Design of Nuclear Reactor Building Structures Applying Seismic Isolation System in a High Seismicity Region –A Feasibility Case Study in Japan-

TETSUO KUBO,TOMOFUMI YAMAMOTO,KUNIHIKO SATO,MASAKAZU JIMBO,TETSUO IMAOKA,YOSHITO UMEKI 한국원자력학회 2014 Nuclear Engineering and Technology Vol.46 No.5

A feasibility study on the seismic design of nuclear reactor buildings with application of a seismic isolation systemis introduced. After the Hyogo-ken Nanbu earthquake in Japan of 1995, seismic isolation technologies have been widelyemployed for commercial buildings. Having become a mature technology, seismic isolation systems can be applied toNPP facilities in areas of high seismicity. Two reactor buildings are discussed, representing the PWR and BWR buildingsin Japan, and the application of seismic isolation systems is discussed. The isolation system employing rubber bearingswith a lead plug positioned (LRB) is examined. Through a series of seismic response analyses using the so-named standarddesign earthquake motions covering the design basis earthquake motions obtained for NPP sites in Japan, the responsesof the seismic isolated reactor buildings are evaluated. It is revealed that for the building structures examined herein: (1)the responses of both isolated buildings and isolating LRBs fulfill the specified design criteria; (2) the responses obtainedfor the isolating LRBs first reach the ultimate condition when intensity of motion is 2.0 to 2.5 times as large as that of thedesign-basis; and (3) the responses of isolated reactor building fall below the range of the prescribed criteria.

A SEISMIC DESIGN OF NUCLEAR REACTOR BUILDING STRUCTURES APPLYING SEISMIC ISOLATION SYSTEM IN A HIGH SEISMICITY REGION -A FEASIBILITY CASE STUDY IN JAPAN

Kubo, Tetsuo,Yamamoto, Tomofumi,Sato, Kunihiko,Jimbo, Masakazu,Imaoka, Tetsuo,Umeki, Yoshito Korean Nuclear Society 2014 Nuclear Engineering and Technology Vol.46 No.5

A feasibility study on the seismic design of nuclear reactor buildings with application of a seismic isolation system is introduced. After the Hyogo-ken Nanbu earthquake in Japan of 1995, seismic isolation technologies have been widely employed for commercial buildings. Having become a mature technology, seismic isolation systems can be applied to NPP facilities in areas of high seismicity. Two reactor buildings are discussed, representing the PWR and BWR buildings in Japan, and the application of seismic isolation systems is discussed. The isolation system employing rubber bearings with a lead plug positioned (LRB) is examined. Through a series of seismic response analyses using the so-named standard design earthquake motions covering the design basis earthquake motions obtained for NPP sites in Japan, the responses of the seismic isolated reactor buildings are evaluated. It is revealed that for the building structures examined herein: (1) the responses of both isolated buildings and isolating LRBs fulfill the specified design criteria; (2) the responses obtained for the isolating LRBs first reach the ultimate condition when intensity of motion is 2.0 to 2.5 times as large as that of the design-basis; and (3) the responses of isolated reactor building fall below the range of the prescribed criteria.

고층 건물에 적용한 면진 시스템의 설치 위치에 따른 지진 응답 분석

김민주,김동욱,김현수,강주원 한국공간구조학회 2018 한국공간구조학회지 Vol.18 No.4

Seismic isolation systems have typically been used in the form of base seams in mid-rise and low-rise buildings. In the case of high-rise buildings, it is difficult to apply the base isolation. In this study, the seismic response was analyzed by changing the installation position of the seismic isolation device in 3D high - rise model. To do this, we used 30-story and 40-story 3D buildings as example structures. Historic earthquakes such as Mexico (1985), Northridge (1994) and Rome Frieta (1989) were applied as earthquake loads. The installation position of the isolation device was changed from floor to floor to floor. The maximum deformation of the seismic isolation system was analyzed and the maximum interlaminar strain and maximum absolute acceleration were analyzed by comparing the LB model with seismic isolation device and the Fixed model, which is the base model without seismic isolation device. If an isolation device is installed on the lower layer, it is most effective in response reduction, but since the structure may become unstable, it is effective to apply it to an effective high-level part. Therefore, engineers must consider both structural efficiency and safety when designing a mid-level isolation system for high-rise buildings.

돔 구조물의 지진응답 저감을 위한 중간 면진장치의 적용

김기철,김수근,강주원,Kim, Gee-Cheol,Kim, Su-Geun,Kang, Joo-Won 한국공간구조학회 2016 한국공간구조학회지 Vol.16 No.4

The seismic isolation system reduces the seismic vibration that is transmitted from foundation to upper structure. This seismic isolation system can be classified into base isolation and mid-story isolation by the installation location. In this study, the seismic behavior of dome structure with mid-story isolation is analyzed to verify the effect of seismic isolation. Mid-story isolation is more effective than base isolation to reduce the seismic responses of roof structure. Also, this isolation would be excellent in structural characteristics and construction.

KALIMER-600 지진해석모델 개발 및 시간이력 지진응답해석

구경회,이재한 한국지진공학회 2007 한국지진공학회논문집 Vol.11 No.3

본 논문에서는 제4세대 소듐냉각고속로(Sodium-Cooled Fast Reactor)의 후보 노형으로 선정된 KALIMER-600에 대한 단순 지진해석모델을 개발하고 시간이력 지진응답해석을 수행하여 수평 면진설계(Seismic Isolation) 기술이 적용된 원자로건물의 주요기기 및 구조물에서의 지진응답 성능을 분석하였다. 개발된 단순 지진해석모델은 원자로건물, 원자로시스템, 주요 기기, 중간 열전달계통 배관, 그리고 면진장치를 포함하며 각각은 상세 유한요소해석을 통한 동특성 비교검증을 통하여 정확성을 검증하였다. 안전정지기준 0.3g의 설계인공지진 하중에 대한 시간이력 지진응답해석을 수행하여 면진설계와 비면진 설계조건에 따른 원자로 주요 부위에서의 층응답스펙트럼을 비교분석한 결과 KALIMER-600의 면진성능이 우수한 것으로 나타났다. In this paper, a simple seismic analysis model of the KALIMER-600 sodium-cooled fast reactor selected to be the candidate of the GEN-IV reactor is developed. By using this model, the seismic time history analysis is carried out to investigate the feasibilities of a seismic isolation design. The developed simple seismic analysis model includes the reactor building, reactor system,, IHTS piping system, steam generator, and seismic isolators. The dynamic characteristics of the simple seismic model are verified with the detailed 3-dimensional finite element analysis for each part of the KALIMER-600 system. By using the developed simple seismic model, the seismic time history analyses for both cases of a seismic isolation and non-isolation design are performed for the artificial time history of a SSE (Safe Shutdown Earthquake) 0.3g. From the comparison of the calculated floor response spectrum, it is verified that the seismically isolated KALIMER-600 reactor building shows a great performance of a seismic isolation and assures a seismic integrity.

지반-구조물 상호작용 효과를 고려한 지진격리시스템이 적용된 원전 격납건물의 지진 취약도 평가

임승현,정형조,김민규,최인길 한국지진공학회 2013 한국지진공학회논문집 Vol.17 No.2

Several researches have been studied to enhance the seismic performance of nuclear power plants (NPPs) by application of seismic isolation. If a seismic base isolation system is applied to NPPs, seismic performance of nuclear power plants should be reevaluated considering the soil-structure interaction effect. The seismic fragility analysis method has been used as a quantitative seismic safety evaluation method for the NPP structures and equipment. In this study, the seismic performance of an isolated NPP is evaluated by seismic fragility curves considering the soil-structure interaction effect. The designed seismic isolation is introduced to a containment building of Shin-Kori NPP which is KSNP (Korean Standard Nuclear Power Plant), to improve its seismic performance. The seismic analysis is performed considering the soil-structure interaction effect by using the linearized model of seismic isolation with SASSI (System for Analysis of Soil-Structure Interaction) program. Finally, the seismic fragility is evaluated based on soil-isolation-structure interaction analysis results.

Influence of pier height on the effectiveness of seismic isolation of friction pendulum bearing for single-track railway bridges

Weikun He,Lizhong Jiang,Biao Wei,Zhenwei Wang 국제구조공학회 2021 Smart Structures and Systems, An International Jou Vol.28 No.2

Friction pendulum bearing (FPB) in bridges with different pier heights has various degrees of effectiveness of seismic isolation. To determine the applicability of FPB under different bridge pier height conditions, this paper focuses on the simply supported girder railway bridges that have three types of piers: solid piers with uniform cross-section, solid piers with non-uniform cross-section, and hollow piers with non-uniform cross-section. All of these bridges are first installed with FPB (isolation bearing) and later with non-isolation bearing, modeled by using OpenSEES finite element software. A shake table test is used to verify the related models. Based on nonlinear dynamic time history analysis, the seismic responses of isolated and non-isolated bridges are compared, and their corresponding seismic isolation ratios are calculated. Further, this paper introduces a fuzzy comprehensive evaluation method to determine the seismic isolation effect of FPB on bridges with different pier heights, by weighing and balancing the isolation ratios of different seismic responses of bridges. The results show that the transverse seismic isolation ratios of FPB are generally larger than the longitudinal seismic isolation ratios. In addition, FPB has poorer seismic isolation effect on tall piers compared with short piers.

Earthquake risk assessment of seismically isolated extradosed bridges with lead rubber bearings

Kim, Dookie,Yi, Jin-Hak,Seo, Hyeong-Yeol,Chang, Chunho Techno-Press 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.29 No.6

This study presents a method to evaluate the seismic risk of an extradosed bridge with seismic isolators of lead rubber bearings (LRBs), and also to show the effectiveness of the LRB isolators on the extradosed bridge, which is one of the relatively flexible and lightly damped structures in terms of seismic risk. Initially, the seismic vulnerability of a structure is evaluated, and then the seismic hazard of a specific site is rated using an earthquake data set and seismic hazard maps in Korea. Then, the seismic risk of the structure is assessed. The nonlinear seismic analyses are carried out to consider plastic deformation of bridge columns and the nonlinear characteristics of soil foundation. To describe the nonlinear behaviour of a column, the ductility demand is adopted, and the moment-curvature relation of a column is assumed to be bilinear hysteretic. The fragility curves are represented as a log-normal distribution function for column damage, movement of superstructure, and cable yielding. And the seismic hazard at a specific site is estimated using the available seismic hazard maps. The results show that in seismically-isolated extradosed bridges under earthquakes, the effectiveness of the isolators is much more noticeable in the columns than the cables and girders.

중ㆍ저층골조에서 면진주기 설정에 따른 면진효과 분석

천영수(Chun Young-Soo),허무원(Hur Moo-Won) 대한건축학회 2008 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.28 No.1(구조계)

Seismic isolation offers an attractive approach for reducing seismic loads in the building and in its components. This paper deals with the seismic isolation effects due to variation in period ratio between superstructure and isolation layer of the building. Seismic isolation effects of the moment-resisting frames with the various period ratio were studied by nonlinear time history analysis, and the guidelines on the stiffness ratio of the superstructure and isolation layer of the building for the effective seismic isolation follow from the results of this study. It is recommended that the isolation period should be greater than 2.5 times of that of the superstructure for the effective seismic isolation.