• Steel and Composite Structures
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• 제11권2호
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• pp.149-168
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• 2011

This paper presents a computational study of column loss scenarios for typical multi-story steel buildings with perimeter moment frames and composite steel-concrete floors. Two prototype buildings (three-story and ten-story) were represented using three-dimensional nonlinear finite element models and explicit dynamic analysis was used to simulate instantaneous loss of a first-story column. Twelve individual column loss scenarios were investigated in the three-story building and four in the ten-story building. This study provides insight into: three-dimensional load redistribution patterns; demands on the steel deck, concrete slab, connections and members; and the impact of framing configuration, building height and column loss location. In the dynamic simulations, demands were least severe for perimeter columns within a moment frame, but the structures also exhibited significant load redistribution for interior column loss scenarios that had no moment connectivity. Composite action was observed to be an important load redistribution mechanism following column loss and the concrete slab and steel deck were subjected to high localized stresses as a result of the composite action. In general, the steel buildings that were evaluated in this study demonstrated appreciable robustness.

• 국제초고층학회논문집
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• 제5권3호
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• pp.177-186
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• 2016

Along the subduction-zone of the western Japanese islands, large earthquakes are expected occur around the middle of this century, and long-period ground motions will reach major urban areas, shaking high-rise buildings violently. Since some old high-rise buildings were designed without considering long-period ground motions, reinforcing such buildings is an important issue. An effective method to reinforce existing high-rise buildings is installing additional dampers. However, a problem with ordinary dampers is that they require reinforcement of surrounding columns and girders to support large reaction forces generated during earthquake ground motion. To solve this problem, a deformation-dependent oil damper was developed. The most attractive feature of this damper is to reduce the damping force at the moment when the frame deformation comes close to its maximum value. Due to this feature, the reinforcement of columns, girders, and foundations are no longer required. The authors applied seismic retrofitting with a deformation-dependent oil damper to an existing 54-story office building (Shinjuku Center Building) located in Shinjuku ward, Tokyo, in 2009 to suppress vibration under the long period earthquake ground motions. The seismic responses were observed in the 2011 Tohoku Earthquake, and it is clarified that the damping ratio was higher and the response lower by 20% as compared to the building without dampers.

• Coupled systems mechanics
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• 제7권2호
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• pp.177-195
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• 2018

Reinforced concrete buildings in a seismically active area can be designed as DCM (medium ductility) or DCH (high ductility) class according to the regulations of Eurocode 8. In this paper, two RC buildings, one with a wall structural system and the other with a frame system, previously designed for DCM and DCH ductility, were analysed by using incremental dynamic analysis in order to study differences in the behaviour of structures between these ductility classes, especially the failure mechanism and ultimate collapse acceleration. Despite the fact that a higher behaviour factor of DCH structures influences lower seismic resistance, in comparison to DCM structures, a strict application of the design and detailing rules of Eurocode 8 in analysed examples caused that the seismic resistance of both frames does not significantly differ. The conclusions were derived for two buildings and do not necessarily apply to other RC structures. Further analysis could make a valuable contribution to the analysis of the behaviour of such buildings and decide between two ductility classes in everyday building design.

• 한국전산구조공학회논문집
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• 제17권4호
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• pp.433-442
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• 2004

본 논문에서는 이웃한 빌딩의 기초가 서로 상이한 경우, 구조물과 지반의 상호작용에 대한 지진응답해석을 하였다. 세 가지 시스템에 대한 두 가지 모델에 대하여 연구하였다. 첫째 모델의 경우에는 빌딩은 프레임모델로 지반은 그리드모델로 설정하였고, 둘째 모델의 경우에는 구조물과 지반을 평면응력과 평면변형률로 모델화하였다. 또한 변형된 관성모멘트는 지반의 탄성모듈과 함께 구조물의 단면력에 영향을 미치므로 함께 고려되었다. 근사해석으로는 유한요소법과 응답스펙트럼이 적용되었으며 제시된 예를 통하여 안전성을 논증하였다.

• 한국공간구조학회논문집
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• 제18권1호
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• pp.117-125
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• 2018

Recently, various building integrated wind power (BIWP) approaches have been used to produce energy by installing wind power generators in high-rise buildings constructed in urban areas. BIWP has advantages in that it does not require support to position the turbine up to the installation height, and the energy produced by the wind turbine can be applied directly to the building. The accurate evaluation of wind speed is important in urban wind power generation. In this study, a wind tunnel test and computational fluid dynamics (CFD) analysis were conducted to evaluate the wind speed for installing wind turbines between buildings. The analysis results showed that the longer the length of the buildings, which had the same height, the larger the wind speed between the two buildings. Furthermore, the narrower the building's width, the higher the wind velocity; these outcomes are due to the increase in the Venturi effect. In addition, the correlation coefficient between the results of the wind tunnel test and the CFD analysis was higher than 0.8, which is a very high value.

• Earthquakes and Structures
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• 제9권2호
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• pp.391-413
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• 2015

Damage of torsionally coupled buildings situated on soil sites has been reported in literature, however no site-specific studies are available for torsionally coupled buildings having site characteristics as a parameter. Effect of torsion is being accounted in seismic codes by the provision of design eccentricity where the dynamic to static eccentricity ratio is a parameter. In this paper, a methodology to determine dynamic to static eccentricity ratio of torsionally coupled buildings has been demonstrated for Delhi region for two torsionally coupled buildings on three soil sites. The variations of average and standard deviations of frame shears for stiff and flexible edges are studied for four eccentricity ratios for the two buildings for the three sites. From the limited studies made, it is observed that the dynamic to static eccentricity ratios observed for site-specific earthquakes are different from Indian seismic code specified value, hence a proposal is made to include a comment in Indian seismic code. Methodology proposed in this paper can be adopted for any region, for the estimation of dynamic to static eccentricity ratio for site specific earthquake.

• 한국공간구조학회논문집
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• 제19권3호
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• pp.33-40
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• 2019

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.

• Journal of the Korean Wood Science and Technology
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• 제45권1호
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• pp.1-11
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• 2017

건축물에서 냉방과 난방에 많은 양의 에너지가 소요되고 있다. 건축은 $CO_2$ 발생을 줄이고 에너지 소비 저감을 위하여 냉 난방 부하를 최소화할 필요성이 있다. 그리고 최근 주거문화는 친환경적이고 실내 쾌적성을 중시하는 방향으로 변화하면서 단독주택의 수요가 증가하고 있다. 국내 단독주택의 구조는 크게 조적조, 콘크리트조, 목조 주택으로 구분할 수 있다. 따라서 본 논문은 세 가지 구조방식(조적, 콘크리트, 목조)으로 구성된 동일 면적 단독주택의 냉 난방 부하와 에너지 요구량을 분석하였다. 구조방식별 벽체, 지붕, 바닥 레이어를 구성하였고, 각 레이어의 열관류율(U-value)은 목조 벽체와 같이 스터드를 고려해주기 위하여 PHPP 계산법을 이용하였다. 또한 스터드 유무에 따른 차이를 비교 분석하기 위하여 목조 벽체에서 스터드를 고려하지 않은 경우(비 스터드)를 분석하였다. 분석은 엑셀을 기반으로 자체 개발한 냉 난방 부하 산출 프로그램(CHLC)과 ECO2를 이용하였다. 냉 난방 부하와 에너지 요구량 결과, 목조 구조가 가장 높은 결과를 보였고 콘크리트 구조는 두 번째로 높은 값을 유지하는 것을 확인하였다. 두 구조방식은 에너지소비 측면에서 불리하다고 판단하였다. 결론적으로, 동일한 조건에서의 조적 구조는 다른 구조방식에 비하여 냉 난방 부하 및 에너지 요구량에 있어 유리하며, 목조 구조에서 스터드로 인한 열교를 제외한다면 에너지소비를 줄일 수 있다고 판단되었다.

• Structural Engineering and Mechanics
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• 제66권5호
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• pp.609-619
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• 2018

When the irregularities occurred in buildings, affect their seismic performance. This paper has focused on one of the types of irregularities at the height that named setback in elevation. For this purpose, several multistorey Reinforced Concrete Moment Resisting Frames (RCMRFs) with different types of setbacks were designed according to new edition of Iranian seismic code. The nonlinear time history analysis was performed to predict the seismic performance of frames subjected to seven input ground motions. The assessment of the seismic performance was done considering both global and local criteria. Results showed that the current edition of Iranian seismic code needs to be modified in order to improve the seismic behaviour of reinforced concrete moment resisting setback buildings. It was also shown that the maximum damages happen at the elements located in the vicinity of the setbacks. Therefore, it is necessary to strengthen these elements by appropriate modification of Iranian seismic code.

• 건축역사연구
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• 제14권3호
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• pp.89-102
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• 2005

Frank Lloyd Wright and Mies van der Rohe are two of the most influential architects in modern architecture. In spite of the different values in their architectural lives, the design of high-rise building had been a continuous matter of primary concern for them. The purpose of this study is to compare the architectural characteristics of the two master architects in terms of building form, structure, function, and envelop skin. glass. Both of them shared with the principle of organic architecture even in the design of high-rise buildings. However, the specific approaches to realize it in high-rise buildings are significantly different. Although they emphasized the integration of building form and structure, Wright regarded the reinforced concrete structure as an organic form-giver, while Mies introduced the steel skeleton structure only as an efficient and flexible building frame. As primary finishing materials for high-rise buildings, glass was used for functional purpose by Wright, but for visual purpose by Mies.