• Advances in Computational Design
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• 제6권1호
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• pp.1-13
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• 2021

Failure of a Multi-storeyed reinforced concrete framed structure occurs when a primary vertical structural component is isolated or made fragile, due to artificial or natural hazards. Load carried by vertical component (column) is transferred to neighbouring columns in the structure, if the neighbouring column is incompetent of holding the extra load, this leads to the progressive failure of neighbouring members and finally to the failure of partial or whole structure. The collapsing system frequently seeks alternative load path in order to stay alive. One of the imperative features of collapse is that the final damage is not relative to the initial damage. In this paper, the effect on the column and beam adjacent to statically removed vertical element in terms of axial force, shear force and bending moment is investigated. Using Alternate load path method, numerical modelling of two dimensional one bay, two bay with variation in storey heights are analysed with FE model in order to obtain better understanding of failure mechanism of multi-storeyed reinforced concrete framed structure. The results indicate that the corner column is more susceptible to progressive collapse when compared to middle column, using this simplified methodology one can easily predict how the structure can be made to stay alive in case of sudden failure of any horizontal or vertical structural element before designing.

• 정보처리학회논문지D
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• 제14D권2호
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• pp.157-168
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• 2007

온라인 분석 처리(On-Line Analytical Processing)에서는 다양한 분석을 효과적으로 처리하기 위해, 다차원 구조의 데이터를 연(column)에 에트리뷰트 값이 표시되는 넓은 형태의 수평 테이블로 표현한다. 관계형 테이블들은 보통 에트리뷰트의 개수에 제한이 있으므로(MS SQLServer와 Oracle은 1,024개 컬럼으로 제한), 이러한 수평 테이블을 직접 저장하기 어렵다. 본 연구에서는 상용 RDBMS에서 제공하는 PIVOT 연산을 이용하여 수평 테이블에 대한 질의를 저장된 수직 테이블에 대한 질의로 변환하는 효율적인 최적화 실행 전략을 제시한다. 우선, 관계 데이터베이스에서 수평 테이블을 차원의 이름을 열로 갖는 수직 테이블로 저장하고, 수평 테이블에 대한 질의를 수직 테이블에 대한 질의로 변환하는 다양한 최적화 전략을 제시한다. 특히, 관계 연산(셀렉션, 프로젝션, 조인 등)에 대한 여러 변환 방법을 제안한다. 이때, 변환된 질의는 여러 가지 방법으로 수행할 수 있으며, 각 방법에 따라 수행 시간이 서로 다르다. 그러므로 PIVOT 연산을 사용하여 변환된 질의를 수행하는 최적화 전략을 제시한다. 마지막으로, 다양한 실험을 통해 여러 질의 트리의 방법에 따라 수행 시간을 측정하여 비교 평가한다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 추계 학술발표회 제20권2호
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• pp.29-32
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• 2008

본 연구에서는 1988년 이후 설계된 많은 구조물들이 내진 성능을 갖추지 못하고 있는 실정이다. 기존 건축물에는 용도상 복잡한 형상의 벽이 붙는 경우가 많으며 대표적인 것으로 날개벽이 있다. 날개벽이 붙는 기둥 및 날개벽이 있으므로 인해 단스팬보화가 되는 보가 생기면 강성이 크나 연성이 줄어드는 등 부재의 전반적인 거동에 영향을 주는 경우가 많다. 이런 부재 모두는 대변형시 전단파괴의 가능성이 있으며 내력열화가 발생하기 쉽다. 또한 이들 부재가 기둥의 역학적 거동, 파괴성상에 커다란 영향을 주는 것은 과거의 지진피해의 조사보고에 의해 지적되고 있다. 이를 위해 현행의 설계에서는 날개벽에 구조 slit를 설치하여 기둥과 절연을 강구하여 기둥내력에는 영향을 미치지 않는 것으로 하여 설계되어지고 있다. 기존 건축물의 내진 성능평가 시 연직부재의 전단내력과 휨 내력의 산정은 가장 중요한 사항으로 간주하여 설계되고 있으나, 현재까지 국내에서는 날개벽이 있는 기둥이 미치는 영향에 대해서는 연구가 전무한 실정이다.

• Steel and Composite Structures
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• 제43권2호
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• pp.139-152
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• 2022

Steel-reinforced concrete (SRC) L-shaped column is the vertical load-bearing member with high spatial adaptability. The seismic behavior of SRC L-shaped column is complex because of their irregular cross sections. In this study, the hysteretic performance of six steel truss reinforced concrete L-shaped columns specimens under the combined loading of compression, bending, shear, and torsion was tested. There were two parameters, i.e., the moment ratio of torsion to bending (γ) and the aspect ratio (column length-to-depth ratio (φ)). The failure process, torsion-displacement hysteresis curves, and bending-displacement hysteresis curves of specimens were obtained, and the failure patterns, hysteresis curves, rigidity degradation, ductility, and energy dissipation were analyzed. The experimental research indicates that the failure mode of the specimen changes from bending failure to bending-shear failure and finally bending-torsion failure with the increase of γ. The torsion-displacement hysteresis curves were pinched in the middle, formed a slip platform, and the phenomenon of "load drop" occurred after the peak load. The bending-displacement hysteresis curves were plump, which shows that the bending capacity of the specimen is better than torsion capacity. The results show that the steel truss reinforced concrete L-shaped columns have good collapse resistance, and the ultimate interstory drift ratio more than that of the Chinese Code of Seismic Design of Building (GB50011-2014), which is sufficient. The average value of displacement ductility coefficient is larger than rotation angle ductility coefficient, indicating that the specimen has a better bending deformation resistance. The specimen that has a more regular section with a small φ has better potential to bear bending moment and torsion evenly and consume more energy under a combined action.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 가을 학술발표논문집(II)
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• pp.456-461
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• 1998

This paper presents the results from a combination of strut-and-tie model and analytical study that investigated the ultimate strength of wall system with frame supports. Strut-and-tie models show reasonable force flows and upper bound solution is compared to the results from FEM analysis. The results shows that two main parameters - transfer girder depth and column width - yield good estimation of the ultimate strength of the system. Vertical and horizontal reinforcements of the transfer girder add few strength to the whole system. The proposed design strength formula shows good agreement with the results from FEM analysis.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1996년도 가을 학술발표회 논문집
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• pp.267-274
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• 1996

Differential shortening of vertical members in high-rise buildings affect other structural members that have to be considered such as horizontal members and exterior cladding. of many elements which affect the total amount of shortening, different loading history mainly comes from the different construction time. Shortening of 66 story concrete columns were investigated and compared according to the different construction time, little difference was found between the total shortening of interior and that of exterior column.

• Interaction and multiscale mechanics
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• 제4권4호
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• pp.321-336
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• 2011

This paper presents the results of static vertical load tests carried out on a model building frame supported by pile groups embedded in cohesionless soil (sand). The effect of soil interaction on displacements and rotation at the column base and also the shears and bending moments in the columns of the building frame were investigated. The experimental results have been compared with those obtained from the finite element analysis and conventional method of analysis. Soil nonlinearity in the lateral direction is characterized by the p-y curves and in the axial direction by nonlinear vertical springs along the length of the piles (${\tau}-z$ curves) at their tips (Q-z curves). The results reveal that the conventional method gives the shear force in the column by about 40-60%, the bending moment at the column top about 20-30% and at the column base about 75-100% more than those from the experimental results. The response of the frame from the experimental results is in good agreement with that obtained by the nonlinear finite element analysis.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 봄 학술발표회 논문집
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• pp.357-362
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• 2000

This Paper presents dynamic analysis of underground R/C Subway Structure, subjected to seismic actions. Earthquakes brought serious damage to RC subway Structure. Foe studying the collapse mechanism of underground RC Subway, seismic of a subway station is simulated in using FEM program ASP2000 of two-dimension based on the path dependent RC elastic model, soil foundation and interfacial models. The shear failure of intermediate vertical columns is founds to be the major cause of the structural collapse. According to FEM simulation of the failure mechanism, it is considered that the RC column would lose axial load carrying capacity after the occurrence of the localized diagonal shear cracks , and sudden failure of the outer frame would be followed. Specially, the shear stress in the middle slab reaches maximum shear capacity. So, the Structure would fail in the middle slab as a result of erasing the vertical ground motion computation.

• Geomechanics and Engineering
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• 제1권1호
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• pp.97-112
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• 2009

The interactions between a granular pile and raft placed on top are investigated using the continuum approach. The compatibility of vertical and radial displacements along the pile - soil interface and of the vertical displacements along the raft - top of ground interfaces are satisfied. Results show that consideration of radial displacement compatibility does not influence the settlement response of or sharing of the applied load between the granular pile and the raft. The percentage load carried by the granular pile (GP) increases with the increase of its stiffness and decreases with the increase of the relative size of raft. The normal stresses at the raft - soil interface decrease with the increase of stiffness of GP and/or relative length of GP. The influences of GP stiffness and relative length of GP are found to be more for relatively large size of raft. The percentage of load transferred to the base of GP increases with the increase of relative size of raft.

• Coupled systems mechanics
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• 제12권5호
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• pp.461-479
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• 2023

The paper deals with the finite element modelling of the free vibration and structural behavior of a particular four-floor reinforced concrete structure subjected to static equivalent seismic loads and supported by a shallow foundation system called SNSF (Spider Net System Footing). The two FE models are a simple 2D Matlab model and a detailed 3D model based on solid elastic elements using Altairworks (Hypermesh and Optistruct). Both models can simulate the soil structure interaction. We concentrate on the behavior of a representative cell involving two columns on five levels. The influence of the boundary conditions on the external vertical planes of the domain are duly studied. The Matlab model appears relevant for a primary estimation of frequencies and stiffness of the whole structure under vertical and lateral loads.