• Computational Structural Engineering
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• v.11 no.1
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• pp.217-226
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• 1998

The purpose of this study is to develop a technique for the shape analysis of plane truss structures under prescribed displacement modes. The shape analysis is performed based on the existence theorem of the solution and the Moore-Penrose generalized inverse matrix. In this paper, the homologous deformation of structures was proposed as prescribed displacement modes, the shape of the structure is determined from these various modes and applied loads. In general, the shape analysis is a kind of inverse problem different from stress analysis, and the governing equation becomes nonlinear. In this regard, Newton-Raphson method was used to solve the nonlinear equation. Three different shape models are investigated as numerical examples to show the accuracy and the effectiveness of the proposed method.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.4A
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• pp.207-215
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• 2012

Structural behavior of built-up compression members with unsymmetric connectors under buckling status has been studied through these experiments. When the distance between adjacent H-300 beams of built-up compression member is 2 m in length, and the H-300 beams are lengthened up to 30 m in length with three-10 m-H-beams by bolts and double arrayed, three specimen having each connector interval 4 m, 5 m, 6 m are experimented for evaluating buckling loads. The buckling loads from the experiments are compared with buckling loads of structural analysis using FEM and buckling loads of Timoshenko Eq. loads in order to figure out how the connectors' interval affects on longitudinal and lateral displacements, also strain of the built-up compression members as well. The result shows that the buckling loads tend to sharply decrease non-linearly according to connectors' interval increases. As well as that, the differences between experimental buckling loads and theoretical buckling loads and between experimental buckling loads and structural analyses buckling loads also have a tendency to be increased as the connector interval increases.

• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.3 s.43
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• pp.1-8
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• 2005

This paper describes a new objective methodology of seismic building damage assessment which is called Advanced Component Method(ACM). ACM is a major attempt to replace the conventional loss estimation procedure, which is based on subjective measures and the opinions of experts, with one that objectively measures both earthquake intensity and the response ol buildings. First, response of typical buildings is obtained analytically by nonlinear seismic static analysis, push-over analyses. The spectral displacement Is used as a measure of earthquake intensity in order to use Capacity Spectrum Method and the damage functions for each building component, both structural and non-structural, are developed as a function of component deformation. Examples of components Include columns, beams, floors, partitions, glazing, etc. A repair/replacement cost model is developed that maps the physical damage to monetary damage for each component. Finally, building response, component damage functions, and cost model were combined probabilistically, using Wonte Carlo simulation techniques, to develop the final damage functions for each building type. Uncertainties in building response resulting from variability in material properties and load assumptions were incorporated in the Latin Hypercube sampling technique. The paper also presents and compares ACM and conventional building loss estimation based on historical damage data and reported loss data.

• Journal of Bio-Environment Control
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• v.26 no.4
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• pp.402-410
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• 2017

The effect of the steel pipe member joint on the design performance of a plastic multi-span greenhouse was analysed through the comparing full-scale experiment and numerical analysis. The design performance of the greenhouse is generally evaluated through numerical analysis, but it is rare to consider the characteristics of the connections or joints of the members. In this study, the effect of the column-gutter beam-rafter-wind break wall joint on the design performance of the whole structure of a plastic multi-span greenhouse was analysed. The numerical results with assuming that the member joint are rigid condition were compared with the full-scale load test results using member joints used in the field. The stiffness of the entire structure was compared using the load-displacement relationship and the change of the load sharing ratio that the main members such as column, rafters, and wind break wall was analysed. The results of the load test were about 40% larger than the numerical result and the member stress was more than twice as large as those of the loaded columns. In order to increase the reliability of the design performance of the greenhouse, it is necessary to develop a numerical analysis model which can consider the characteristics of various joints.

• Computational Structural Engineering
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• v.4 no.1
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• pp.133-142
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• 1991

A mathematical hysteretic model has been developed to analytically reproduce the experimental hysteretic behavior of reinforced concrete members. This mode[2, 3] can simulate the nonlinear response of reinforced concrete members with sufficient accuacy, which are characterized by following important hysteretic behaviors: stiffness degradation, strength deterioration and shear effect. In order to illustrate the capabilities of the proposed mathematical model, numerical examples are presented with the reproduction of experimental hysteretic behavior of RC members and frames.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.259-262
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• 2010

최근 건물형상의 다양화로 인하여 수직부재의 불규칙성이 빈번하게 발생하면서 전통적인 보-기둥 형식의 골조에서 변형된 보와 기둥의 특징을 공유하고 있는 경사기둥의 사용빈도가 높아지고 있다. 현재 국내에서 사용하고 있는 내진설계방법은 강도에 근거를 둔 설계법으로서 구조물이 탄성상태에서 저항해야 하는 부재력에 근거하고 있다. 그러나 기준에서 규정하고 있는 또는 그 이상의 지진하중이 구조물에 가해지는 경우에 구조물은 비선형 거동을 하게 되는데 구조물이 비선형 거동을 할 때에는 탄성상태와는 다른 힘의 흐름을 나타내게 된다. 본 논문에서는 12층 철골 모멘트 골조 구조물에 대하여 횡력에 저항하는 정형화된 골조와 경사기둥을 이용한 골조의 내진성능 및 비선형 거동을 조사하였다. 그 결과 강기둥-약보로 설계된 정형화된 구조물에서는 보의 소성힌지가 계속적으로 발달하면서 구조물이 저항하는데 반하여 경사기둥을 가진 구조물은 비탄성 상태에서 경사기둥에 인접한 기둥부재로 하중이 집중되면서 정형골조에 비하여 붕괴 메카니즘이 훨씬 작은 변위에서 발생하는 것을 볼 수 있었다.

• Journal of Korean Society of Steel Construction
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• v.20 no.3
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• pp.377-387
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• 2008

The post-buckling behavior of slender members, such as the chord of truss structures generally implies extreme strength degradation. The buckling strength is usually determined as the performance of the compressed steel members, so it is important to understand the exact buckling behavior of a member in order to design the entire structure. A target analytical model is usually divided by beam or shell element when we simulate the buckling behavior of a compressed steel member such as atruss member. In this case, it is possible to accurately obtain the behavior, but such would be expensive and would require experience inanalysis even in monotonic loading. In this paper, we propose a consistent and convenient method to analyze the post-buckling behavior of elastoplastic compression members. The present methods are formulated to satisfy the second law of thermodynamics. Three numerical examples were tested to determine the validity of the proposed model in cyclic loading with comparable F.E.M results.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.5
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• pp.567-576
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• 2023

In general, RC beam members are designed as flexural members, considering only the bending load. However, in actual buildings, axial and bending load are simultaneously applied due to the continuity between members. As a result, the bending strength of the RC beam member increases, but the displacement decreases, and cracks are mainly concentrated in the center of the beam. Therefore, in this study, the bending performance of both normal and strengthened RC beam using carbon fiber sheets subjected to combined axial and bending load was experimentally evaluated. The carbon fiber sheets were wrapped around the middle of the specimens, and axial and bending load were applied simultaneously to the beams. The magnitude of the axial force and the effects of carbon fiber sheet reinforcement on the deformed shape, bending strength, deflection, and ductility of the RC beams were analyzed. The results show that as the applied axial force increased, the maximum bending strength increased, but the ductility decreased 64%. The bending strength of the strengthened beams increased up to 27%, the maximum deflection decreased around 8% and the ductility increased by up to 43%.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.891-896
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• 2008

Behavior of the existing tunnel in the jointed rocks was affected by the adjacent slope excavation. In this study, large scale model tests were conducted. To investigate the tunnel distortion depending on the excavated slope angle and the joint dip of the ground performed model tests were numerically back analyzed. Consequently, as the joint dip and slope angle became larger, the tunnel distortion was tended to be larger. Ground displacement was also greatly dependent on the joint dip and the excavated slope angle, which indicated the possibility of the optimal slope reinforcement.

• Journal of the Korea Concrete Institute
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• v.22 no.1
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• pp.11-18
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• 2010

In this study, a procedure of performance-based design for the seismic retrofit of reinforced concrete columns strengthened by steel jackets has been presented. In order to predict the target displacement of retrofitted columns, a nonlinear analysis of reinforced concrete columns retrofitted with steel jackets has been developed based on a segmental model with the fiber cross-sectional approach. The seismic displacement level of retrofitted columns is estimated both by the direct displacement-based design method and by the displacement coefficient method. In examples of seismic retrofitted columns, the current seismic retrofit procedure gives good results in improvements of displacement levels and displacement ductilities of retrofitted columns.