• Wind and Structures
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• 제4권2호
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• pp.147-162
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• 2001

This paper presents an analytical method which takes into account the non-linearity of individual members, and discusses some case study results. It also discusses the relationship between member non-elastic behavior and excitation duration, and the relationship between member fracture and overall structure behavior. It is clearly demonstrated that the frame already shows almost unstable behavior due to long-columnization just before the occurrence of a column fracture. Then, a column fracture immediately induces a structural collapse mechanism.

• 국제초고층학회논문집
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• 제6권1호
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• pp.33-47
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• 2017

This mixed-use Raffles City (RCH) development is located near the Qiantang River in Hangzhou, the capital of Zhejiang province, located southwest of Shanghai, China. The project incorporates retail, offices, housing, and hotel facilities and marks the site of a cultural landscape within the Quianjiang New Town Area. The project is composed of two 250-meter-tall twisting towers with a form of vibrant waves, along with a commercial podium and three stories of basement car parking. It reaches a height of 60 stories, presenting views both to and from the Qiantang River and West Lake areas, with a total floor area of almost 400,000 square meters. A composite moment frame plus concrete core structural system was adopted for the tower structures. Concrete filled steel tubular (CFT) columns together with steel reinforced concrete (SRC) beams form the outer moment frame of the towers' structure. The internal slabs and floor beams are of reinforced concrete. This paper presents the engineering design and construction of this highly complex project. Through comprehensive discussion and careful elaboration, some conclusions are reached, which serve as a reference guide for the design and construction of similar free-form, hybrid, mix-use buildings.

• 한국강구조학회 논문집
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• 제22권1호
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• pp.75-85
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• 2010

최근 초고층 건물에 구조적인 측면을 고려한 Freeform Structure라는 개념이 등장하고 있다. 이 형태는 Diagrid, Cantilevered, Tilted로 대변될 수 있는데 특히 다이아 그리드 시스템은 횡저항에 하중의 흐름을 가새 프레임을 따라 분산시킴으로써 효율적인 거동을 보이기 때문에 그만큼 부재를 경량화시킬 수가 있다. 그러나 Diagrid 구조시스템의 내진성능 평가를 위한 반응수정계수에 대한 신뢰성 있는 자료가 없기 때문에 우수한 내진성능이 예상됨에도 불구하고 기타구조 등으로 설계되고 있다. 본 연구에서는 실대형 실험을 통해 Diagrid 구조의 반응수정계수를 실험적으로 규명하고자 한다.

• 국제초고층학회논문집
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• 제5권4호
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• pp.251-262
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• 2016

Tall Buildings have been one of the most prominent symbols of economic growth for nearly a century. Yet, in the aftermath of the tragedies of September 11, "signature" Tall buildings have become the focus of much debate. The structural systems today are undergoing a major evolution to address the ability of providing flexibility in the design and use of the building together with sustainability (Green) and cost-effective system. This paper describes a new invented structural system, evolutionary structural analysis and design of Tall buildings, which involves the entire analysis process, including conceptual and design stages and comparison with the existing Tall building. This study presents an new innovative structural system, Beehive (Hexagrid), for Tall buildings. The final results are achieved by modeling an 80 story Tall building with the optimized angle and topology of hexagon members by using a computer analysis, ETABS finite element analysis. The objective function of this system is to use one structural system in order to both maximize Eigen frequency for resisting dynamic responses and minimize mean compliance for static responses. Finite element analysis is carried out by using standardized materials. Optimal Hexagrid topologies with the highest stiffness are finally determined to resist both static and dynamic behaviors. Holistic design integration approaches between structures and facades to save energy for environmental control are studied. Innovative design ideas to control structural motion as well as to utilize that motion to harness energy are discussed. Considering abundant emergence of tall buildings all over the world in recent years, the importance of the studies presented in this paper cannot be overemphasized for constructing more sustainable built environments.

• 복합신소재구조학회 논문집
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• 제2권4호
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• pp.28-34
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• 2011

본 연구는 인공지진파 및 기록 지진파를 이용하여, KBC2009 규준으로 설계된 강구조 건물의 거대 건물에 대한 내력 여유도를 평가하는 것을 목표로 하고 있다. 이 논문에서는 검정에 있어서 콘크리트 슬래브로 층강성이 고정되어 있는 2-D 프레임을 고려하였고, 각각의 프레임을 구성하고 있는 보와 기둥 부재는 각 부재단에 소성힌지를 적용하였다. 검정에 사용한 해석법은 응답 스펙트럼을 이용한 모드 해석과 기록 및 인공지진파를 이용한 시간이력해석을 선택하여 모델의 거동을 조사하였으며 해석에서는 P-delta 효과를 고려한다.

• Earthquakes and Structures
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• 제2권2호
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• pp.171-187
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• 2011

Rational scaling of design earthquake ground motions for tall buildings is essential for safer, risk-based design of tall buildings. This paper provides the structural designers with an insight for more rational scaling based on drift and input energy demands. Since a resonant sinusoidal motion can be an approximate critical excitation to elastic and inelastic structures under the constraint of acceleration or velocity power, a resonant sinusoidal motion with variable period and duration is used as an input wave of the near-field and far-field ground motions. This enables one to understand clearly the relation of the intensity normalization index of ground motion (maximum acceleration, maximum velocity, acceleration power, velocity power) with the response performance (peak interstory drift, total input energy). It is proved that, when the maximum ground velocity is adopted as the normalization index, the maximum interstory drift exhibits a stable property irrespective of the number of stories. It is further shown that, when the velocity power is adopted as the normalization index, the total input energy exhibits a stable property irrespective of the number of stories. It is finally concluded that the former property on peak drift can hold for the practical design response spectrum-compatible ground motions.

• Earthquakes and Structures
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• 제7권4호
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• pp.571-586
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• 2014

This paper presents experimental and numerical study on seismic performance of a super tall steel tower structure. The steel tower, with a height of 388 meters, employs a steel space truss with spiral steel columns to serve as its main lateral load resisting system. Moreover, this space truss was surrounded by the spiral steel columns to form a steel mega system in order to support a 12-story platform building which is located from the height of 230 meters to 263 meters. A 1/40 scaled model for this tower structure was made and tested on shake table under a series of one- and two-dimensional earthquake excitations with gradually increasing acceleration amplitudes. The test model performed elastically up to the seismic excitations representing the earthquakes with a return period of 475 years, and the test model also survived with limited damages under the seismic excitations representing the earthquakes with a return period 2475 years. A finite element model for the prototype structure was further developed and verified. It was noted that the model predictions on dynamic properties and displacement responses agreed reasonably well with test results. The maximum inter-story drift of the tower structure was obtained, and the stress in the steel members was investigated. Results indicated that larger displacement responses were observed for the section from the height of 50 meters to 100 meters in the tower structure. For structural design, applicable measures should be adopted to increase the stiffness and ductility for this section in order to avoid excessive deformations, and to improve the serviceability of the prototype structure.

• 국제초고층학회논문집
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• 제5권3호
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• pp.195-203
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• 2016

Shear wall structures have been widely used in high-rise buildings during the past decades, mainly due to their good overall performance, large lateral stiffness, and high load-carrying capacity. However, traditional reinforced concrete wall structures are prone to brittle failure under seismic actions. In order to improve the seismic behavior of traditional shear walls, this paper presents three different metal energy-dissipation shear wall systems, including coupled shear wall with energy-dissipating steel link beams, frame with buckling-restrained steel plate shear wall structure, and coupled shear wall with buckling-restrained steel plate shear wall. Constructional details, experimental studies, and calculation analyses are also introduced in this paper.

• Earthquakes and Structures
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• 제19권3호
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• pp.197-214
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• 2020

Diagrid structures have been introduced as a fairly modern lateral load-resisting system in the design of high-rise buildings. In this paper, a novel diagrid system called tube-in-tube diagrid building is introduced and assessed through pushover and incremental dynamic analyses. The main objectives of this paper are to find the optimum angle of interior and exterior diagrid tube and evaluate the efficiency of diagrid core on the probability of collapse comparing to the conventional diagrid system. Finally, the seismic performance factors of the proposed system are validated according to the FEMA P695 methodology. To achieve these, 36-story diagrid buildings with various external and internal diagonal angles are designed and then 3-D nonlinear models of these structures developed in PERFORM-3D. The results show that weight of steel material highly depends on diagonal angle of exterior tube. Adding diagrid core generally increases the over-strength factor and collapse margin ratio of tall diagrid buildings confirming high seismic safety margin for tube-in-tube diagrid buildings under severe excitations. Collapse probabilities of both structural systems under MCE records are less than 10%. Finally, response modification factor of 3.0 and over-strength factor of 2.0 and 2.5 are proposed for design of typical diagrid and tube-in-tube diagrid buildings, respectively.

• 국제초고층학회논문집
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• 제4권3호
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• pp.171-180
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• 2015

A shaking table test was conducted at the E-Defense shaking table facility to investigate the damage and collapse behavior of a steel high-rise building under exceedingly large ground motions. The specimen is a one-third scale 18-story steel moment frame designed and constructed according to design specifications and practices used in the 1980s and 1990s. The shaking table tests used a long-duration, long-period ground motion simulated for a sequential Tokai, Nankai, and Nankai earthquake scenario. The building specimen was subjected to a series of progressively increasing scaled motions until it completely collapsed. The damage to the steel frame began through the yielding of beams along lower stories and column bases of the first story. After several excitations by increasing scaled motions, cracks initiated at the welded moment connections and fractures in the beam flanges spread to the lower stories. As the shear strength of each story decreased, the drifts of lower stories increased and the frame finally collapsed and settled on the supporting frame. From the test, a typical progression of collapse for a tall steel moment frame was obtained, and the hysteretic behavior of steel structural members including deterioration due to local buckling and fracture were observed. The results provide important information for further understanding and an accurate numerical simulation of collapse behavior.