• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.1
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• pp.59-67
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• 2014

A dynamic analysis is carried out to provide an evaluation method of running safety for a PSC box bridge located on the Gyung-Bu high speed railway. The numerical models of bridge and train vehicle are developed in detail with corresponding interaction system. Three dimensional skeleton element model of PSC box bridge and 38-degree-of-freedom of vehicle are adopted from the existing properties of KTX bridge and train vehicle. Analysed three direction rotations of vehicle on the bridge and ground tracks are compared for running speeds up to 500 km/h with 10 km/h constant increments. The comparison of the rotations will be an improved evaluation method of Running Safety in stead of the existing standard method.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.5 no.1
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• pp.123-132
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• 1985

The flexibility of base material gives considerable influences on seismic responses of a structure. The effects of relative stiffness between super-structure and base material on dynamic soil-structure interaction are evaluated by parametric studies. Two 5-story buildings are used for the study; one is shearwall structure with relatively higher fundamental frequency and the other is frame structure with relatively lower fundamental frequency. The structures are modeled as beam-sticks coupled with springs and dashpots representing the base material. Dynamic equilibrium equations of the soil-structure interaction system are sloved by mode superposition method using Rosset modal damping values. Soil-structure interaction effect is found to be major concern in seismic analysis of shearwall structure in most cases while it seldom becomes engineering problem in frame-type structure. It is also found that seismic responses at lower elevation of the super-structure are amplified though they decrease at higher elevation as soil-structure interaction effects of the system increase.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.10 no.3
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• pp.67-75
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• 1990

A geometrically nonlinear analysis procedure including the damping effects is presented for the investigation of the dynamic post-divergence and post-flutter behavior of a non-conservative system. The dynamic nonlinear analysis of plane frame structure subjected to conservative and non-conservative forces is carried out by solving the equations of motion using Newmark method. Numerical results are presented to demonstrate the effects of the internal and external damping forces in the conservative and non-conservative systems.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.327-330
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• 2009

PSC 박스 교량의 시공 중 거동 특성을 고려하기 위하여 뼈대 요소를 이용한 시공단계의 설계가 수행되고 있다. 그러나 PSC 박스 교량 중 곡선 램프교 등의 경우는 교량의 외측 및 내측의 변위 및 응력 값이 현저히 다르다. 따라서 PSC 박스 교량의 텐던량 및 시공 중 긴장력이 외측 및 내측에서 다르게 산정되어야 함에도 불구하고 현실적으로는 계산이 불가능하여 같은 양의 텐던과 부적절한 긴장력을 사용하고 있어 비효율적인 설계와 시공이 이루어지고 있다. 이러한 문제점을 해결하기 위하여 내외측의 텐던량을 다르게 고려할 수 있고 교량의 내외측 반력, 응력, 변위 분포를 얻을 수 있는 3차원 해석이 필수적으로 요구 되고 있다. 본 연구에서는 PSC 박스 교량의 3차원 거동 해석을 위하여 텐던 및 크리프, 건조수축을 반영한 준적합 쉘요소를 이용하여 수치해석을 수행하였으며 크리프 및 건조수축의 특성은 ACI코드와 CEB/FIP 코드를 적용하여 비교분석하였다. 각각의 결과 값이 상이한 경우도 있지만 대체로 두 코드는 비슷한 양상을 보였으며 CEB/FIP 가 좀 더 경제적인 설계가 됨을 알 수 있었다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.04a
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• pp.45-52
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• 2003

A finite element procedure to estimate ultimate strength of space frames considering spread of plasticity is presented. The improved displacement field is introduced based on inclusion of second order terms of finite rotations. All the nonlinear terms due to bending and torsional moment as well as axial force are precisely considered. The concept of plastic hinge is introduced and the incremental load/displacement method is applied for the elasto-plastic analysis. The initial yield surface is defined based on the residual stress and the full plastification surface is considered under the combined action of axial force, bending and torsional moments. The elasto-plastic stiffness matrices are derived using the flow rule and the normality condition of the limit function. Finite element solutions for ultimate strength of space frames are compared with available solutions and experimental results.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1989.10a
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• pp.34-39
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• 1989

Recent trends in design standards development have encouraged the use of probabilistic limit sate design concepts. Reliability analysis adopted in those advanced countries have the potentials that they afford for symplifying the design Process arid placing it on a consistent reliability based for various construction materials. This study is proposed in the reliability analysis of plane frame structures using second-order moment method(Level-II they). Lind-Hasofer's minimum distance method is use in the derivation of an mathematical algorithm as well as an determination of Correlation cofficients, reliability index and total reliability index depending on the multiple failure modes. In addition. This study is employed as a practical tool for the approximate reliability analysis. Results of the numerincal analysis showed that the difference between the reliability index of the failure probability of the multiple failure modes and the total reliability index of the failure probability with the simultaneous failure modes deviated nearly 3∼10% depending on tile performance functions.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2001.10a
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• pp.327-334
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• 2001

This paper presents a non-linear analysis procedure for plane frame structures by finite element formulation with assumptions of Timoshenko beam theory. Finite element displacement method based on Lagrangian formulation is used and two-noded and isoparametric line element is adopted to represent finite element model. The layered approach is used for the elasto-plastic analysis of the plane frame structures with rectangular and I cross sections. A load incremental method combined with the tangent stiffness and the initial stiffness methods for each load increment is used for the solution of non-linear equations. Numerical examples are presented to investigate the behavior and the accuracy of the elasto-plastic non-linear application and the results of this study are compared with other solutions using the concept of plastic hinge.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.10a
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• pp.287-294
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• 2002

An automatic design method of steel frames using nonlinear analysis is developed. The geometric nonlinearity is considered by the use of stability functions. A direct search method is used as an automatic design technique. The unit value of each member is evaluated by using LRFD Interaction equation. The member with the largest unit value Is replaced one by one with an adjacent larger member selected in the database. The weight of the steel frame is taken as an objective function. Load-carrying capacities, deflections, interstory drifts, and ductility requirement are used as constraint functions. Case study of a three-dimensional two story frame are presented.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.10a
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• pp.403-410
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• 1999

General1y, H-section is used for columns and beams in the middle and low steel building, But it has a strong and weak axis. Thus if H-section is used for columns, the structure needs reinforcement on the weak axis. Therefore recently, square holler section(S.H.S) is used for columns because it is able to coiler the vulnerability of H-section. Structural analysis is usually executed under the assumption that connections are either ideally pinned joint or fully rigid joint. Actually all connections are semi-rigid which possess a rotational stiffness. Therefore it can be designed economically as using the property of connections which has a rotational stiffness. This paper presents a prediction model curve which is fitted Kishi-Chen power Model about the behavior of connection between H-beam and S.H.S column. Non-linear analysis program was considered the non-linearity of semi-rigid connection and the geometrical non-linearity under the effect of axial force. It was programed by FORTRAN90 and Visual Basic.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1997.10a
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• pp.111-118
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• 1997

Generally, H-section is used for columns and beams in the middle and low building steel structure, But it has a axis and a weak axis. Thus if H-section is used for columns, the structure needs reinforcement on the weak axis. Therefore recently, square hollow section(S.H.S) is used for columns because it is able to cover the vulnerability of H-section. Structural analysis is usually executed under the assumption that connections are either ideally pinned joint or fully joint. Actually all connections are semi-rigid which possess a rotational stiffness. Therefore it can be designed economically as using the property of connections which has a rotational stiffness. This paper presents a prediction model curve which is fitted with Kishi-Chen Power Model about the behavior of connection between H-beam and S.H.S column in the previous experimental paper. It also suggests the new analysis algorithm considering the non-linear of semi-rigid connection and the geometrical non-linear under the effect of axial force.