• Wind and Structures
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• v.11 no.5
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• pp.391-411
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• 2008

A design procedure of stabilizing cable is proposed using buffeting analysis to stabilize the seesaw-like motion of the free cantilevered structure of a cable-stayed bridge during its construction. The bridge examined is a composite cable-stayed bridge having a main span length of 500 m. Based on the buffeting analysis, the stress in bare structure exceeded the allowable limit and a set of stabilizing cable was planned to mitigate the responses. The most efficient positions of the hold-down stabilizing cables were numerically investigated by means of an FE-based buffeting analysis and the required dimensions and pretension of the stabilizing cables were also calculated. The proposed stabilizing measure would be expected to secure the aerodynamic safety of a cantilevered structure under construction with considerable mitigation of buffeting responses.

• Magazine of the Korean Society of Agricultural Engineers
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• v.42 no.1
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• pp.105-112
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• 2000

This paper deals with the free vibrations of columns immersed in fluid. The column model is based on the classical Bernoulli-euler theory which neblects the effects of rotatory inerital and shear deformation. The eccentricity and rotatory inertial of the concentrated mass at the top are taken into accuont. In the governing equation for the free vibration of column, thedensity of immersed part was midified to account for theadded fluid mass. The govering differential equations are solved numerically using the corresponding boundary conditions. The lowest four natural frequencies and corresponding mode shapes are calculated over a range of non-dimensional system parameters ; the mas density ration of fluid to column, the ratio of fluid depth to span length, the ratio of tip mass to total column mass, the dimensionless mass moment of inertia, and the eccentricity.

• Proceedings of the KSR Conference
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• 2003.10b
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• pp.591-595
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• 2003

Field measurements were conducted to analysis lateral dynamic characteristics of existing steel plate girder railway bridges without ballast. Three bridges which have 9m, 12m, 18m span length in Kyoung-Bu Line were selected for test. According to the each bridge, dynamic lateral deflections and accelerations were measured. From the present study, it was observed that dynamic lateral amplification phenomena caused by a fluctuation of lateral force were occurred under the current running circumstances. Lateral deflections were occurred below than that specified in Korean railway bridge specification, but lateral accelerations is a match for vertical accelerations. From now on, it is in need a plan to reduce lateral accelerations for the conventional railway Line speed up.

• Proceedings of the KWS Conference
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• 2006.10a
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• pp.51-53
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• 2006

The purpose of this study is to establish the predictive equation of angular distortion and longitudinal shrinkage force at the intermittent fillet weldment using FEA and experiment. The angular distortion and shrinkage force of the intermittent fillet weldment linearly increases with an increase in the ratio of weld length(Lw) to weld span(Ls). Based on the results, The predictive equation of distortion at the intermittent fillet weldment was defined as a linear function of Lw/Ls and the predictive equation of the distortion for continuous fillet weldment.

• Proceeding of KASS Symposium
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• 2008.05a
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• pp.227-231
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• 2008

There are many retractable roof structures in the world. Retractable roofs will be classified by various factors and user, for example span length, moving mechanism, opening system, roof material and utility in over 100 examples. Therefore I will present considerations in architectural planning and structural design.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.7A
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• pp.542-549
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• 2005

In this paper, the optimal pump light power of optical phase conjugator (OPC) and the compensation characteristics of distorted WDM channel signals are numerically investigated, when the OPC with highly-nonlinear dispersion shifted fiber (HNL-DSF) not be placed at the mid-way of total transmission length. The total dispersion of former half section and latter half section is assumed to be same each other in this approach. It is confirmed that, in WDM transmission systems with OPC deviated from the mid-way, the pump light power for best compensation must be flexible selected depending on the OPC position. This optimal pump light power is gradually increased as the OPC is gradually closer to the receiver. Consequently, it is possible to establish the compensation system independent on the OPC position by setting optimal pump light power connected with the OPC position.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.61-62
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• 2010

This paper provides an analysis using statistical method on the basis of database (DB) of bridge inspection reports performed by KISTEC from 1995 to 2007. Measured impact factors of total 36 railway bridges were classified by the span length, type of bridges and natural frequency. The fundamental frequency and the impact factors of inspected bridge are compared with formulas specified in both domestic and foreign railway bridge design codes.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.169-170
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• 2010

This paper mainly investigates the adequate number of cross beams at the IPSC(Incrementally PreStressed Concrete) girder bridge. The length of span was fixed to 50m and FE model was analyzed by using the ABAQUS program. The models for the numerical tests result in the cases whose number of cross beam are respectively 2, 3, 4, and 5. All of the results of proposed numerical tests satisfy the current specifications. Also, based on the results, we can determine the optimal number of cross beam for more economic design and improvement in constructability.

• Interaction and multiscale mechanics
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• v.2 no.4
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• pp.431-454
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• 2009

This paper presents a simple model for studying the dynamic response of multi-span bridges resting on piers with different heights and subjected to earthquake forces acting transversely to the bridge, but varying spatially along its length. The analysis is carried out using the modal superposition technique, while the solution of the resulting integral-differential equations is obtained via the Laplace transformation. It has been found that the piers' height and the quality of the foundation soil can affect significantly the dynamic behavior of such bridges. Typical examples showing the effectiveness of the method are presented with useful results listed.

• Structural Engineering and Mechanics
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• v.48 no.2
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• pp.275-289
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• 2013

The cross sections of multi-span beams are sometimes suddenly increased at the interior support of continuous beams to resist high negative moment. An earlier study on elastic lateral torsional buckling of stepped beams was conducted to propose new design equations. This research aims to continue the earlier study by considering the effect of inelastic buckling of stepped beams subjected to pure bending and general loading condition. A three-dimensional finite element-program ABAQUS and a statistical program MINITAB were used in the development of new design equations. The inelastic lateral torsional buckling strengths of 36 and 27 models for singly and doubly stepped beams, respectively, were investigated. The general loading condition consists of 15 loading cases based on the number of inflection point within the unbraced length of the stepped beams. The combined effects of residual stresses and geometrical imperfection were also considered to evaluate the inelastic buckling strengths. The proposed equations in this study will definitely improve current design methods for the inelastic lateral-torsional buckling of stepped beams and will increase efficiency in building and bridge design.