• 한국전산구조공학회논문집
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• 제25권1호
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• pp.19-26
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• 2012

본 논문에서는 강판벽이 설치된 골조 구조물의 연쇄붕괴 거동을 비선형 정적 pushdown 해석을 이용하여 평가하였다. 해석모델은 중력하중에 대해서 설계된 2층 2경간 철골구조물이며, 중앙 기둥을 제거하고 하중을 서서히 증가시키며 하중-변위 관계를 구하였다. 구조물의 전체적인 거동뿐만 아니라 부분적인 응력과 변형을 파악하기 위하여 ABAQUS를 이용한 유한요소해석을 수행하였다. 해석을 통해서 구조물의 경간 길이 및 설치된 강판의 두께의 변화에 따른 연쇄붕괴 거동을 평가하였으며, 샛기둥을 이용하여 강판을 분할하고 분할된 강판의 위치에 따른 연쇄붕괴 성능의 변화를 관찰하였다. 해석결과에 따르면 경간의 길이가 증가할수록 연쇄붕괴를 방지하기 위하여 요구되는 강판의 두께 또한 증가하며, 분할된 강판의 수가 증가할수록 연쇄붕괴에 대한 저항성능이 약간 증가하지만 그 영향은 그리 크지 않은 것으로 나타났다. 또한 개구부로 인하여 일부 경간에만 강판이 설치된 경우에도 연쇄붕괴 저항성능이 어느 정도 증가하는 것으로 나타났다.

• Steel and Composite Structures
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• 제24권1호
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• pp.37-52
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• 2017

To quantitatively assess the safety against seismic collapse of eccentrically braced steel frame (EBSF) system, 24 typical EBSFs with K-shape and V-shape braces with seismic precautionary intensities 8 and 9 were designed complying with China seismic design code and relative codes to constitute archetype space of this structure system. In the archetype space, the collapse probability of the structural system under maximum considered earthquakes (MCE) was researched. The results show that the structures possess necessary safety against seismic collapse when they respectively encounter the maximum considered earthquakes corresponding to their seismic precautionary levels, and their collapse probabilities increase with increasing seismic precautionary intensities. Moreover, the EBSFs with V-shape braces have smaller collapse probability, thus greater capacity against seismic collapse than those with K-shape braces.

• Earthquakes and Structures
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• 제5권3호
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• pp.277-296
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• 2013

Margin of safety against potential of progressive collapse is among important features of a structural system. Often eccentricity in plan of a building causes concentration of damage, thus adversely affects its progressive collapse safety margin. In this paper the progressive collapse of symmetric and asymmetric 3-story reinforced concrete ordinary moment resisting frame buildings subjected to the earthquake ground motions are studied. The asymmetric buildings have 5%, 15% and 25% mass eccentricity. The distribution of the damage and spread of the collapse is investigated using nonlinear time history analyses. Results show that potential of the progressive collapse at both stiff and flexible edges of the buildings increases with increase in the level of asymmetry in buildings. It is also demonstrated that "drift" as a more easily available global response parameter is a good measure of the potential of progressive collapse rather than much difficult-to-calculate local response parameter of "number of collapse plastic hinges".

• 한국전산구조공학회논문집
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• 제34권6호
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• pp.417-426
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• 2021

최근 현장작업을 최소화할 수 있는 PC(Precast Concrete) 건축공법의 적용이 급속하게 활성화되고 있다. 그러나 PC 공법은 시공 중, 특히 부재간 일체화 이전에 구조적 성능을 발휘하기 어렵고 완공 후에도 접합부의 일체성을 확보하기 어려워 연쇄붕괴에 취약하다. PC 건축물에서는 다양한 PC 부재간 접합 상세가 존재하며, 국내외 구조/시공 상세가 현격히 다르다. 그러나 국내 PC 시스템의 시스템과 상세 특성을 반영한 연쇄붕괴에 대한 연구는 매우 미비하다. 따라서, 본 연구에서는 국내에서 주로 사용하는 PC 구조시스템과 접합부 구조/시공 상세를 조사 분석하였다. 이를 기반으로 국내에서 사용되는 전형적인 PC 시스템의 유형을 설정하고 상기 PC 시스템의 연쇄붕괴방지성능을 평가하기 위하여 비선형 유한요소해석을 수행하였다. 해석결과를 바탕으로 국내에서 주로 사용된 PC 구조시스템의 연쇄붕괴방지 성능을 평가하고 구조설계시 고려사항을 제안하였다.

• 전산구조공학
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• 제20권4호
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• pp.51-57
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• 2007

• 전산구조공학
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• 제20권4호
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• pp.58-62
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• 2007

• 한국시스템다이내믹스연구
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• 제13권1호
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• pp.63-80
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• 2012

This paper is aiming at providing the systems thinking perspective on the collapse of the savings and loan banking system in Korea. Two causal loop diagrams are developed to conduct the analysis: The first is focusing on the structural problems included in the establishment of S&L banking in 1990s. The later is developed based on the project financing mechanism by controlling the credit standard required during the due diligence. The result of this study shows that the main cause of the collapse of the S&L banking is the structural problem connected to real estate market including the failure of regulation.

• Structural Engineering and Mechanics
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• 제6권7호
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• pp.773-784
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• 1998

To assess the collapse risk of transmission line structures subject to natural hazards, it is important to identify what hazard may cause the structural collapse. In Australia and many other countries, a large proportion of failures of transmission line structures are caused by severe thunderstorms. Because the wind loads generated by thunderstorms are not only random but time-variant as well, a time-dependent structural reliability approach for the risk assessment of transmission line structures is essential. However, a lack of appropriate stochastic models for thunderstorm winds usually makes this kind of analysis impossible. The intention of the paper is to propose a stochastic model that could realistically and accurately simulate wind loading due to severe thunderstorms. With the proposed thunderstorm model, the collapse risk of transmission line structures under severe thunderstorms is assessed numerically based on the computed failure probability of the structure.

• Nuclear Engineering and Technology
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• 제50권8호
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• pp.1402-1411
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• 2018

Nuclear-related facilities can be detrimentally affected by ground vibrations due to the collapse of adjacent cooling towers in nuclear power plants. To reduce this hazard risk, a design-oriented acceleration response spectrum (ARS) was proposed to predict the dynamic responses of nuclear-related facilities subjected to ground vibrations. For this purpose, 20 computational cases were performed based on cooling tower-soil numerical models developed in previous studies. This resulted in about 2664 ground vibration records to build a basic database and five complementary databases with consideration of primary factors that influence ground vibrations. Afterwards, these databases were applied to generate the design-oriented ARS using a response spectrum analysis approach. The proposed design-oriented ARS covers a wide range of natural periods up to 6 s and consists of an ascending portion, a plateau, and two connected descending portions. Spectral parameters were formulated based on statistical analysis. The spectrum was verified by comparing the representative acceleration magnitudes obtained from the design-oriented ARS with those from computational cases using cooling tower-soil numerical models with reasonable consistency.

• Earthquakes and Structures
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• 제9권1호
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• pp.49-71
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• 2015

The present paper aims at evaluating damage and collapse behavior of low-rise buildings with unidirectional mass irregularities in plan (torsional buildings). In previous earthquake events, such buildings have been exposed to extensive damages and even total collapse in some cases. To investigate the performance and collapse behavior of such buildings from probabilistic points of view, three-dimensional three and six-story reinforced concrete models with unidirectional mass eccentricities ranging from 0% to 30% and designed with modern seismic design code provisions specific to intermediate ductility class were subjected to nonlinear static as well as extensive nonlinear incremental dynamic analysis (IDA) under a set of far-field real ground motions containing 21 two-component records. Performance of each model was then examined by means of calculating conventional seismic design parameters including the response reduction (R), structural overstrength (${\Omega}$) and structural ductility (${\mu}$) factors, calculation of probability distribution of maximum inter-story drift responses in two orthogonal directions and calculation collapse margin ratio (CMR) as an indicator of performance. Results demonstrate that substantial differences exist between the behavior of regular and irregular buildings in terms of lateral load capacity and collapse margin ratio. Also, results indicate that current seismic design parameters could be non-conservative for buildings with high levels of plan eccentricity and such structures do not meet the target "life safety" performance level based on safety margin against collapse. The adverse effects of plan irregularity on collapse safety of structures are more pronounced as the number of stories increases.