• Title/Summary/Keyword: 3 Story Building Structure

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Simultaneous Optimization of Hybrid Mid-Story Isolation System and Building Structure (하이브리드 중간층 지진 격리 시스템과 빌딩 구조물의 동시 최적화)

  • Kim, Hyun-Su;Kang, Joo-Won
    • Journal of Korean Association for Spatial Structures
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    • v.19 no.3
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    • pp.51-59
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    • 2019
  • 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.

Performance Evaluation of Vibration Control of a Smart Top-Story Isolation System (스마트 최상층 면진시스템의 진동제어 성능평가)

  • Kang, Joo-Won;Kim, Tae-Ho;Kim, Hyun-Su
    • Journal of Korean Association for Spatial Structures
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    • v.10 no.3
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    • pp.49-56
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    • 2010
  • In this study, the control performance of a smart top-story isolation system for tall buildings subjected to wind excitation was investigated. To this end, a 77-story tall building structure was employed and wind loads obtained from wind tunnel test were used for numerical simulations. The top-story of an example structure is separated from the main structure by a smart base isolation system composed of friction pendulum systems (FPS) and MR dampers. The primary purpose of the smart top-story isolation system is to mitigate the dynamic responses of the main structure, but the excessive movement of the isolated top story may cause the unstableness of the building structure. Therefore, the skyhook control algorithm was used to effectively reduce both responses of the isolated top story and the main structure. The control performance of the proposed smart top-story isolation system was investigated in comparison with that of the passive top-story isolation system. It has been shown from numerical simulation results that the smart top-story isolation system can effectively reduce wind-induced responses of the example building structure compared to the passive top-story isolation system with reduction of the top-story movement.

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Evaluation of Progressive Collapse Resisting Capacity of Tall Buildings

  • Kwon, Kwangho;Park, Seromi;Kim, Jinkoo
    • International Journal of High-Rise Buildings
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    • v.1 no.3
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    • pp.229-235
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    • 2012
  • In this paper the progressive collapse potential of building structures designed for real construction projects were evaluated based on arbitrary column removal scenario using various alternate path methods specified in the GSA guidelines. The analysis model structures are a 22-story reinforced concrete moment frames with core wall building and a 44-story interior concrete core and exterior steel diagrid structure. The progressive collapse resisting capacities of the model structures were evaluated using the linear static, nonlinear static, and nonlinear dynamic analyses. The linear static analysis results showed that progressive collapse occurred in the 22-story model structure when an interior column was removed. However the structure turned out to be safe according to the nonlinear static and dynamic analyses. Similar results were observed in the 44-story diagrid structure. Based on the analysis results, it was concluded that, compared with nonlinear analysis procedures, the linear static method is conservative in the prediction of progressive collapse resisting capacity of building structure based on arbitrary column removal scenario.

Application of three-dimensional modified inclined braces to control soft-story buildings

  • Nodehi, Soroush;Zahrai, Seyed Mehdi
    • Structural Engineering and Mechanics
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    • v.83 no.6
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    • pp.811-824
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    • 2022
  • Despite its disadvantages, soft story can reduce the damage to the upper floors by concentrating drift in that specific story provided that large drifts are avoided. Gapped-Inclined Brace (GIB) with reduced P-delta effects and the control of soft story stiffness makes it possible to take advantage of the soft story in buildings and increase their capacity for energy dissipation. OpenSees software is used in this study to validate and modify the GIB model's shortcomings. Also, the analysis method for this element is changed for design. The modified element is evaluated in 3D analysis. Finally, to retrofit an existing building, this element is used. Based on the Iranian seismic code, a six-story reinforced concrete building is modelled and studied with 3D analysis. In this building, the construction shortcomings and elimination of infills on the ground floor cause the formation of a soft story. Results of nonlinear static analysis, nonlinear dynamic, and incremental dynamic analysis using both components of seismic acceleration applied to the structure at different angles and the fragility curves indicate the improvement of the retrofitted structure's performance using the modified element to reach the required performance level following the retrofit code.

Study on The Damage Location Detection of Shear Building Structures Using The Degradation Ratio of Story Stiffness (층강성 손상비를 이용한 전단형 건물의 손상위치 추정에 관한 연구)

  • Yoo, Seok-Hyung
    • Journal of the Architectural Institute of Korea Structure & Construction
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    • v.34 no.2
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    • pp.3-10
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    • 2018
  • Damage location and extent of structure could be detected by the inverse analysis on dynamic response properties such as frequencies and mode shapes. In practice the measured difference of natural frequencies represent the stiffness change reliably, however the measured mode shape is insensitive for stiffness change, but provides spatial information of damage. The damage detection index on shear building structures is formulated in this study. The damage detection index could be estimated from mode shape and srory stiffness of undamaged structure and frequency difference between undamaged and damaged structure. For the verification of the observed damage detection method, the numerical analysis of Matlab and MIDAS and shacking table test were performed. In results, the damage index of damaged story was estimated so higher than undamaged stories that indicates the damaged story apparently.

Structural Design of Mid-Story SI Tall-building with RC Frame Placed on Steel Structure

  • Isobe, Tomonobu;Aono, Hideshi
    • International Journal of High-Rise Buildings
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    • v.10 no.3
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    • pp.173-178
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    • 2021
  • In this paper we introduce Shinagawa HEART, located in Shinagawa district, Tokyo. It is a mixed-use building with residences on the upper floors, offices on the lower floors, and commercial uses on the first and second floors, and is intended to meet the various needs of a building on the border between residential and commercial areas. The upper floors of the building are made of reinforced concrete, while the middle and lower floors are made of steel with CFT columns. First, an overview of the structural plan of the building is presented. Next, the adoption of the middle layer seismic isolation and the switch between the lower steel structure and the upper reinforced concrete structure, which are the features of this building, are explained. Finally, the construction method adopted to achieve the design performance is explained.

A Study on Optimum Distribution of Story Shear Force Coefficient for Seismic Design of Multi-story Structure

  • Oh, Sang Hoon;Jeon, Jongsoo
    • International Journal of High-Rise Buildings
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    • v.3 no.2
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    • pp.121-145
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    • 2014
  • The story shear force distributions of most seismic design codes generally reflect the influences of higher vibration modes based on the elastic deformations of structures. However, as the seismic design allows for the plastic behavior of a structure, the story shear force distribution shall be effective after it is yielded due to earthquake excitation. Hence this study conducted numerical analyses on the story shear force distributions of most seismic design codes to find out the characteristics of how a structure is damaged between stories. Analysis results show that the more forces are distributed onto high stories, the lower its concentration is and the more energy is absorbed. From the results, this study proposes the optimum story shear force distribution and its calculation formula that make the damages uniformly distributed onto whole stories. Consequently, the story damage distribution from the optimum calculation formula was considerably more stable than existing seismic design codes.

Structural Design of Nakanoshima Festival Tower

  • Okada, Ken;Yoshida, Satoshi
    • International Journal of High-Rise Buildings
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    • v.3 no.3
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    • pp.173-183
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    • 2014
  • Nakanoshima Festival Tower is a 200 m high-rise complex building which contains a renewed 2700-seat capacity concert hall known as "Festival Hall" and offices including headquarter of a news company. In order to build up an office tower on the hall which requires large open space, a giant truss system is employed. The giant trusses being composed of mega-trusses and belt-trusses support all the building weight above them and transfer the load to the outside of the hall. The building also requires high seismic resistance performance for a news company. Application of mid-story seismic isolation enables the building to satisfy high-level seismic resistance criteria.

Shaking Table Test of a Full Scale 3 Story Steel Frame with Friction Dampers (마찰형 감쇠장치가 설치된 실물크기 3층 철골프레임의 진동대 실험)

  • Bae, Chun-Hee;Kim, Yeon-Whan;Lee, Sang-Hyun;Park, Young-Pil
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.17 no.9
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    • pp.862-873
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    • 2007
  • Energy dissipation devices can be considered as an alternative for the seismic performance enhancement of existing structures based on the strengthened seismic design code. In this study, seismic response mitigation effects of friction dampers are investigated through the shaking table test of a full scale 3 story building structure. Frist, the bilinear force-displacement relationship of a structure-brace-friction damper system and the effect of brace-friction damper on the increase of frequency and damping ratio are identified. Second, frequency, displacement, and torque dependent characteristics of the friction damper are investigated by using harmonic load excitation tests. Finally, the shaking table tests are performed for a full scale 3 story steel frame. System identification results using random signal excitation indicated that brace-friction damper increased structural damping ratio and frequency, and El Centro earthquake test showed that brace-friction damper reduced the peak displacement and acceleration significantly. In particular, it was observed that the damping effect due to friction damper becomed obvious when the structure was excited by more intensive load causing frequent slippage of the friction dampers.

System Identification of the Three Story Building Structure with a Controller (제어기가 설치된 3층 건물의 시스템 식별)

  • 주석준
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 1999.10a
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    • pp.203-211
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    • 1999
  • Threr are several methods in protecting the building structures from dynamic loads such as an earthquake and a wind. Among them applying a control force to the building structure is one of the methods to decrease the vibration. The most important and difficult problem in the active control is to obtain the mathematical model of the building structure with a controller. the effective active controller can be designed from the exact model of the system In this paper the three story test building with an active mass driver is identified experimentally. the system matrices corresponding to the experimental building are found and verified with the experimentally-obtained transfer functions and responses efficiently.

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