하이브리드 중간층 지진격리시스템의 고층 건물 진동 제어 성능 평가

김현수,강주원 한국공간구조학회 2018 한국공간구조학회지 Vol.18 No.3

A base isolation system is widely used to reduce seismic responses of low-rise buildings. This system cannot be effectively applied to high-rise buildings because the initial stiffness of the high-rise building with the base isolation system maintains almost the same as the building without the base isolation system to set the yield shear force of the base isolation system larger than the design wind load. To solve this problem, the mid-story isolation system was proposed and applied to many buildings. The mid-story isolation system has two major objectives; first to reduce peak story drift and second to reduce peak drift of the isolation story. Usually, these two objectives are in conflict. In this study, a hybrid mid-story isolation system for a tall building is proposed. A MR (magnetorheological) damper was used to develop the hybrid mid-story isolation system. An existing building with mid-story isolation system, that is “Shiodome Sumitomo Building” a high rise building having a large atrium in the lower levels, was used for control performance evaluation of the hybrid mid-story isolation system. Fuzzy logic controller and genetic algorithm were used to develop the control algorithm for the hybrid mid-story isolation system. It can be seen from analytical results that the hybrid mid-story isolation system can provide better control performance than the ordinary mid-story isolation system and the design process developed in this study is useful for preliminary design of the hybrid mid-story isolation system for a tall building.

지도학습과 강화학습을 이용한 준능동 중간층면진시스템의 최적설계

강주원,김현수,Kang, Joo-Won,Kim, Hyun-Su 한국공간구조학회 2021 한국공간구조학회지 Vol.21 No.4

A mid-story isolation system was proposed for seismic response reduction of high-rise buildings and presented good control performance. Control performance of a mid-story isolation system was enhanced by introducing semi-active control devices into isolation systems. Seismic response reduction capacity of a semi-active mid-story isolation system mainly depends on effect of control algorithm. AI(Artificial Intelligence)-based control algorithm was developed for control of a semi-active mid-story isolation system in this study. For this research, an practical structure of Shiodome Sumitomo building in Japan which has a mid-story isolation system was used as an example structure. An MR (magnetorheological) damper was used to make a semi-active mid-story isolation system in example model. In numerical simulation, seismic response prediction model was generated by one of supervised learning model, i.e. an RNN (Recurrent Neural Network). Deep Q-network (DQN) out of reinforcement learning algorithms was employed to develop control algorithm The numerical simulation results presented that the DQN algorithm can effectively control a semi-active mid-story isolation system resulting in successful reduction of seismic responses.

하이브리드 중간층 지진 격리 시스템과 빌딩 구조물의 동시 최적화

강주원,김현수 한국공간구조학회 2019 한국공간구조학회지 Vol.19 No.3

A hybrid mid-story seismic isolation system with a smart damper has been proposed to mitigate seismic responses of tall buildings. Based on previous research, a hybrid mid-story seismic isolation system can provide effective control performance for reduction of seismic responses of tall buildings. Structural design of the hybrid mid-story seismic isolation system is generally performed after completion of structural design of a building structure. This design concept is called as an iterative design which is a general design process for structures and control devices. In the iterative design process, optimal design solution for the structure and control system is changed at each design stage. To solve this problem, the integrated optimal design method for the hybrid mid-story seismic isolation system and building structure was proposed in this study. An existing building with mid-story isolation system, i.e. Shiodome Sumitomo Building, was selected as an example structure for more realistic study. The hybrid mid-story isolation system in this study was composed of MR (magnetorheological) dampers. The stiffnessess and damping coefficients of the example building, maximum capacity of MR damper, and stiffness of isolation bearing were simultaneously optimized. Multi-objective genetic optimization method was employed for the simultaneous optimization of the example structure and the mid-story seismic isolation system. The optimization results show that the simultaneous optimization method can provide better control performance than the passive mid-story isolation system with reduction of structural materials.

중간층 면진시스템 설치 위치에 따른 고층건물의 지진응답 분석

김가영,이영락,김현수,강주원 한국공간구조학회 2017 한국공간구조학회지 Vol.17 No.4

Base isolation system is generally used for low-rise buildings. For high-rise buildings subjected to earthquake loads, a mid-story isolation system was proposed and applied to practical engineering. In this study, seismic responses of high-rise buildings considering the installation story of the mid-story isolation system were evaluated. To do this, the 20-story and 30-story building were used as example structures. Historical earthquakes such as Kobe (1995), Northridge (1994) and Loma Prieta (1989) earthquakes were employed applied as earthquake excitations. The installation location of the mid-story isolation system was changed from the bottom of the 1st floor to the bottom of the top floor. The seismic responses of the example building were investigated by changing the location of the isolation layer. Based on the analytical results, when the seismic isolation system is applied, story drift ratio and acceleration response are reduced compared to the case without the isolation system. When the isolation layer is located on the lower part of the building, it is most effective. However, in that case, the possibility that the structure is unstable increases. Therefore, an engineer should consider both structural efficiency and safety when a mid-story isolation system for a high-rise building is designed.

면진장치 특성 변화에 따른 중간층 면진시스템의 지진응답 평가

김현수,김수근,강주원 한국공간구조학회 2018 한국공간구조학회지 Vol.18 No.1

As the number of high-rise buildings increases, a mid-story isolation system has been proposed for high-rise buildings. Due to structural problems, an appropriate isolation layer displacement is required for an isolation system. In this study, the mid-story isolation system was designed and the seismic response of the structure was investigated by varying the yield strength and the horizontal stiffness of the seismic isolation system. To do this, a model with an isolation layer at the bottom of 15th floor of a 20-story building was used as an example structure. Kobe(1995) and Nihonkai-Chubu(1983) earthquake are used as earthquake excitations. The yield strength and the horizontal stiffness of the seismic isolation system were varied to determine the seismic displacement and the story drift ratio of the structure. Based on the analytical results, as the yield strength and horizontal stiffness increase, the displacement of the isolation layer decreases. The story drift ratio decreases and then increases. The displacement of the isolation layer and the story drift ratio are inversely proportional. Increasing the displacement of the isolation layer to reduce the story drift ratio can cause the structure to become unstable. Therefore, an engineer should choose the appropriate yield strength and horizontal stiffness in consideration of the safety and efficiency of the structure when a mid-story isolation system for a high-rise building is designed.

Optimal Design of Smart Mid‑Story Isolated Control System for a High‑Rise Building

김현수,강주원 한국강구조학회 2019 International Journal of Steel Structures Vol.19 No.6

Mid-story isolation systems have previously been studied for decrease of the earthquake induced responses of high-rise buildings. The systems have been successfully applied to several buildings in Korea and Japan. Structural designers usually have to ensure that both the peak story and isolator drifts are within permissible limits. However, these two objectives conflict with each other. To solve this problem, a smart mid-story isolation system can be used for tall buildings. The system is composed of rubber bearings and magnetorheological (MR) dampers. The system was employed for an existing structure to reduce both the isolator and story drift. The control efficiency of smart mid-story isolator was evaluated based on a passive system. An artificial seismic load was made for numerical analyses for both systems. A fuzzy soft-computing technique with a multi-objective optimization was adopted to make control algorithm for decrease of both the inter-story and isolator drift. A numerical analysis results presents that the proposed method can effectively decrease the seismic-induced inter-story and isolator drift in the example of a tall building.

평면 비정형 구조물에 적용된 중간층 면진 시스템의 지진 응답 제어 성능 분석

박효선,김현수,강주원,Park, Hyo-Sun,Kim, Hyun-Su,Kang, Joo-Won 한국공간구조학회 2019 한국공간구조학회지 Vol.19 No.2

In this study, the seismic response is investigated by using a relatively low-rise building under torsion-prone conditions and three seismic loads with change of the location of the seismic isolation system. LRB (Lead Rubber Bearing) was used for the seismic isolator applied to the analytical model. Fixed model without seismic isolation system was set as a basic model and LB models using seismic isolation system were compared. The maximum story drift ratio and the maximum torsional angle were evaluated by using the position of the seismic layer as a variable. It was confirmed that the isolation device is effective for torsional control of planar irregular structures. Also, it was shown that the applicability of the mid-story seismic isolation system. Numerical analyses results presented that an isolator installed in the lower layer provided good control performance for the maximum story drift ratio and the maximum torsional angle simultaneously.

RNN 모델을 이용한 스마트 중간층 면진시스템의 제어성능 평가

김현수 한국산학기술학회 2020 한국산학기술학회논문지 Vol.21 No.1

The seismic response reduction capacity of a smart mid-story isolation system was investigated using the RNN model in this study. For this purpose, an RNN model was developed to make a dynamic response prediction of building structures subjected to seismic loads. An existing tall building with a mid-story isolation system was selected as an example structure for realistic research. A smart mid-story isolation system was comprised of an MR damper instead of existing lead dampers. The RNN model predicted the seismic responses accurately compared to those of the FEM model. The simulation time of the RNN model can be reduced significantly compared to the FEM model. After the numerical simulations, the smart mid-story isolation system could effectively reduce the seismic responses of the existing building compared to the conventional mid-story isolation system. 본 논문에서는 RNN 순환 신경망 (Recurrent Neural Network) 모델을 사용하여 스마트 중간층 면진 시스템의 지진 응답 제어 성능을 수치 해석을 통하여 검토하였다. 이를 위해서 지진 하중을 받는 건물의 동적 지진 응답 예측을 위한 RNN 모델을 개발하였다. 보다 실제적인 연구를 위하여 중간층 면진 시스템이 설치된 실존하는 건물인 시오도메 스미토모 건물을 예제 구조물로 선택하였다. 스마트 중간층 면진 시스템은 기존의 납 댐퍼를 대신하여 MR (Magnetorheological) 댐퍼를 사용하여 구성하였다. 그 외 고무 베어링이나 강재 댐퍼는 그대로 사용 하였다. 수치 해석을 통하여 개발된 RNN 모델이 기존의 FEM (Finite Element Method) 모델과 비교해서 매우 정확한 응답을 예측하는 것을 확인할 수 있었다. RNN 모델을 사용하면 자유도가 많은 FEM 모델을 사용한 경우에 비하여 해석 시간을 대폭 줄일 수 있다. 개발된 RNN 모델을 사용한 수치 해석 결과 스마트 중간층 면진 시스템이 기존의 수동 중간층 면진 시스템에 비하여 구조물의 지진 응답을 대폭 저감시킬 수 있는 것을 확인할 수 있었다.

주상 복합 구조물에 적용된 중간층 면진 시스템의 성능 검토

김현수,김윤태,박광섭 한국공간구조학회 2019 한국공간구조학회지 Vol.19 No.3

A seismic isolation system is one of the most effective control devices used for mitigating the structural responses due to earthquake loads. This system is generally used as a type of base isolation system for low- and mid-rise building structures. If the base isolation technique is applied to high-rise buildings, a lot of problems may be induced such as the movement of isolation bearings during severe wind loads, the stability problem of bearings under large compression forces. Therefore, a mid-story isolation system was proposed for seismic protection of high-rise buildings. Residence-commerce complex buildings in Korea have vertical irregularity because shear wall type and frame type structures are vertically connected. This problem can be also solved by the mid-story isolation system. An effective analytical method using super elements and substructures was proposed in this study. This method was used to investigate control performance of mid-story isolation system for residence-commerce complex buildings subjected to seismic loads. Based on numerical analyses, it was shown that the mid-story isolation system can effectively reduce seismic responses of residence-commerce complex tall 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.