• KSCE Journal of Civil and Environmental Engineering Research
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• v.2 no.3
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• pp.67-74
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• 1982

The dynamic behaviour of an elastically supported finite beam subjected to an axial force and moving loads with acceleration is investigated. Within the Euler beam theory the solutions are obtained by using finite Fourier and Laplace transformation methods with respect to space and time variable. Integrations involved in the theoretical results are carried out by Simpson's rule. From the results of the theoretical analysis, it is evident that dynamic behaviour of the beam are affected remarkably by acceleration and axial force.

• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.6 s.40
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• pp.1-11
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• 2004

In the previous study(1), the finite element method was used for the vertical vibration analysis of suspension bridge considering the effects of the shear deformation and the rotary inertia under moving load. This study firstly performs the eigenvalue analysis for the free vertical vibration of suspension bridge using FEM analysis. Next the equations of motion considering interaction between suspension bridge and vehicles/train are derived using mode superposition method. And dynamic analysis was performed using the Newmark $\beta$ Method. Finally through the numerical examples, the dynamic responses of bridges by this study are investigated.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.3
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• pp.92-95
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• 2019

In this paper, a novel laser-based non-contact and non-destructive stress measurement technique is newly proposed for measuring stress in steel structural members. As the demand of stress monitoring in structural members is increased, various non-destructive techniques are being applied to the field of structural health monitoring. Spectroscopic techniques are non-contact technique and widely used for chemical identification of target materials. Especially, piezospectroscopic technique is a residual stress measurement technique in thermal barrier coatings. Although the piezospectroscopic technique has high possibility of measuring structural stress in steel members, the technique has been rarely applied to this field. In this paper, piezospectroscopy-based stress measurement technique is, therefore, proposed for measuring stress in steel structural member. To do that, alumina particles have been coated onto a specimen of a structural steel rod using a thermal spray coating technique. And then, an uniaxial compression test has been conducted to the specimen to collect each fluorescence spectrum under different loading conditions. Finally, the linear relation of spectral shift and applied compressive stress of the specimen has been experimentally established.

• Journal of Korean Society of Steel Construction
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• v.13 no.2
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• pp.163-176
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• 2001

In this paper, the stress resultants and displacements of simply supported curved girder based on the flexural torsional theory considering torsional warping effects are analyzed. And elastic equations of continuous curved girder are obtained by using energy method. Also, bending moment warping torsional moment diagram, pure torsional moment diagram, shearing force diagram, and deflection diagram of continuos curved girder bridge subjecting to vertical loads and uniform loads are presented.

• 한국방재학회:학술대회논문집
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• 2010.02a
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• pp.79.2-79.2
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• 2010

실제 교량 바닥판의 거동은 반복하중에 의한 피로누적 손상에 의해 발생되므로 성능분석을 위해서는 피로 실험결과를 통한 구조거동 분석이 이루어져야 할 것이다. 이에 본 논문에서는 현재 개발 중인 초간편 강합성 바닥판의 피로성능을 파악하기 위해 일점 재하 방식으로 반복 하중을 재하 하였다. 실험체의 거동을 파악하기 위해 변위계를 설치하여 변위를 측정하였고 이 실험의 결과로 신형식 바닥판인 초간편 강합성 바닥판의 피로 파괴 양상을 알 수 있었으며 피로 곡선을 얻을 수 있었다. 하지만 바닥판의 파괴요인 중 외부 환경적 요인과 실제 차량 하중 이동을 모사한 윤하중 재하 시 피로 성능에 대한 연구가 추가로 이루어져야 할 것으로 판단된다.

• Journal of the Korea Concrete Institute
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• v.18 no.5 s.95
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• pp.695-702
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• 2006

The stress distribution and the critical stresses in concrete pavements were analyzed using formulations in the transformed field domains when dual-wheel single-, tandem-, and tridem-axle loads were applied. First the accuracy of the transformed field domain analysis results was verified by comparing with the finite element analysis results. Then, the stress distribution along the longitudinal and transverse directions was investigated, and the effects of slab thickness, concrete elastic modulus, and foundation stiffness on the stress distribution were studied. The effect of the tire contact pressure related to the tire print area was also studied, and the location of the critical stress occurrence in concrete pavements was finally investigated. From this study, it was found that the critical concrete stress due to multi-axle loads became larger as the concrete elastic modulus increased, the slab thickness increased, and the foundation stiffness decreased. The number of axles did not tend to affect the critical stress ratio except for a small foundation stiffness value with which the critical stress ratio became significantly larger as the number of axles increased. The critical stress location in the transverse direction tended to move into the interior as the tire contact pressure increased, the concrete elastic modulus increased, the slab thickness increased, and the foundation stiffness decreased. The critical stress location in the longitudinal direction was under the axle for single- and tandem-axle loads, but for tridem-axle loads, it tended to move under the middle axle from the outer axles as the concrete elastic modulus and/or slab thickness increased and the foundation stiffness decreased.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.3A
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• pp.211-219
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• 2010

The design concept of high speed railway bridges is applied to a method for increasing the stiffness of existing bridge structures considering the impact factor by a static load. Generally, the process of structural design would be relied upon an advanced foreign technology. However, the dynamic amplification factor (DAF) and dynamic capacity assessment of high speed railway bridges may be conducted essentially a detailed estimation because the resonance phenomenon is affected by the long length (380 m) and high speed (300 km/h) moving of a high speed railway (Korea Train eXpress: KTX). Therefore, this study will be examined the dynamic capacity of the typical PSC Box Girder high speed railway bridge efficiently, and offered the basic information for the reasonable structural design. For this, the static analysis is conducted considering the load line diagram of KTX based upon existing references. In addition, the KTX moving load is transformed into the time series load considering various analytical variables. The time history analysis is assessed reasonable using the transformed time series load. At that time, analytical variables for calculating the time series load are considered loading node distance, time increment and KTX velocity variation etc. The dynamic capacity of the PSC Box Girder high speed railway bridge is examined based upon the FE analysis result systematically. The structural safety is assessed quantitatively in accordance with the related regulation of the inside and outside of the country.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.409_411
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• 2009

국내의 송전선 지지물 설계는 전기설비기술기준과 한국전력공사 송전설계기준에 근거하여 적용되며, 철탑하중에 큰 비중을 갖는 풍하중기준은 1985년 기상청의 풍속 데이터를 반영하여 1987년경에 제정된 지침을 지금까지 적용하고 있다. 당시 제정된 설계기준에서는 지역별 풍속 차이에 따라 I, II, III, 지역 및 울릉도로 구분하여 차등 적용하는 설계개념으로 주변여건을 고려하지 않고 동일한 지역내에 위치하고 있는 송전지지물의 경우에는 동일한 풍하중을 적용하는 방식이다. 최근 해외 철탑설계기준과 국내 건축물 설계기준에서는 전산기술의 발달로 국부적인 지형영향을 고려하여 철탑별로 개별적인 풍하중을 산정하는 방식을 채택하고 있다. 본 논문에서는 상용 송전선로 설계가 진행되고 있는 군산-새만금 예정 경과지 가운데 지형조건을 고려한 풍속할증이 요구되는 개소에 대한 설계 풍하중 검토사례를 소개한다.

• Geotechnical Engineering
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• v.10 no.1
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• pp.7-18
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• 1994

A new model for describing the behavior of clay under monotonic and cyclic loading is proposed. This model uses the hyperbolic representation for the stress -strain relationship in overconsolidated state and it describes undrained effective stress path on the basis of the critical state theory. The developed constitutive model by using an energy dissipation equation can describe the behavior of clay in heavily overconsolidated state as u.ell as lightly overconsolidated state under monotonic loading. In order to extend the model for the behavior of clay under cyclic loading, a shift function of undrained stress spacing ratio is introduced in the constitutive model developed for monotonlc loading. A single additional parameter is required to represent the cyclic effect and it can be reasonably deter mined from the test results. The measured behavior in undrained cyclic triaxial tests has been easily and precisely predicted by the newly developed constitutive model.

• Aerospace Engineering and Technology
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• v.12 no.1
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• pp.73-80
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• 2013

In this study, a numerical analysis based on CFD methods has been conducted to predict the aerodynamic coefficients and aerodynamic loads of KSLV-II configuration designed at the system design phase. By the effects of exclusion of engine cowls of prior configuration, axial force and normal force decreased and center of pressure was much moved to the nose direction. Also, aerodynamic loads at flight and on the launch pad were predicted for structural load analysis. The computed results will be used for mission analysis and structural analysis at the next design phase.