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Dive into the research topics where Jong-Won Kwark is active.

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Featured researches published by Jong-Won Kwark.


Journal of the Korean Society for Railway | 2013

Three Dimensional Model for Dynamic Moving Load Analysis of a PSC-I Girder Railway Bridge

Jeong-Rae Cho; Dong-Seok Kim; Young-Jin Kim; Jong-Won Kwark; Seung Yup Jang

In this paper we evaluated dynamic stability, considering the effects of modeling and analysis methods on moving load analysis, for which a sophisticated 3 dimensional model of a PSC-I type girder bridge was used. For this purpose, we suggested a reasonable modeling method and the physical properties of the concrete and ballasted track system involved. We also analyzed the response characteristics according to: 1) the type of track system; 2) whether or not the track was modeled; 3) whether or not the distance between the girder center and the bearing were considered; 4) the analysis method (i.e., direct integral and modal analysis); 5) whether or not the frequency was filtered.


Journal of the Korean Society for Railway | 2012

Dynamic Characteristics of Simply Supported Single Span Bridges for KTX and HEMU using Design Diagram

Jeong-Rae Cho; Keunhee Cho; Jong-Won Kwark; Young-Jin Kim

This paper presents the ERRI design diagrams of KTX and HEMU applicable to simply supported single span bridges, and analyzes the dynamic characteristics and design considerations of the bridges under KTX and HEMU using the diagrams. The design diagrams of KTX and HEMU are calculated for the bridges with 25m, 30m, 35m and 40m span lengths, which are widely used for simple bridge in Korea. From the design diagrams, the dynamic characteristics of the bridges with the selected span lengths are analyzed. In addition, the design consideration is discussed to satisfy the design requirement of acceleration. It is desirable for the bridge with 25m span length to avoid resonance both for KTX and HEMU. Since larger responses are expected for HEMU in the bridge with 30m span length, and for KTX in the bridge with 35m and 40m span length, the bridges should be planned to have enough mass satifying acceleration requirement at resonance, or to avoid the resonance.


Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit | 2016

Determination of the optimal span length to minimize resonance effects in bridges on high-speed lines

Jeong-Rae Cho; Kilje Jung; Keunhee Cho; Jong-Won Kwark; Young-Jin Kim; Byung-Suk Kim

This paper revisits the creation and cancellation of the dynamic resonance phenomenon that occurs in bridge structures on high-speed lines when crossed by wheel loads. The resonance and its cancellation are mathematically formulated for a Bernoulli-type beam with general boundary conditions and subjected to loads moving at a regular spacing. The resonance of the bridge caused by the travelling loads occurs, regardless of the mode shape, when the natural frequency of the structure coincides with the loading frequency produced by the loads moving at a constant speed. In this study, the dependency of the cancellation phenomenon on the mode shape is determined based on the boundary conditions of the structure. In addition, the optimal span length that suppresses the response at resonance is proposed using the cancellation phenomenon for a simple beam with pinned-pinned, clamped-clamped and clamped-pinned boundary conditions; and a simply supported continuous beam.


Journal of The Earthquake Engineering Society of Korea | 2007

The Pseudo-Dynamic Test for the Seismic Retrofit System Utilizing Existing Bridge Bearings

Im-Jong Kwahk; Chang-Beck Cho; Young-Jin Kim; Jong-Won Kwark

In this study, an approach that installs seismic isolation bearings was proposed for the seismic retrofit of the existing bridges. The method that replaces all existing bearings with seismic isolators was proposed already. However, in this study, we recommend to utilize the existing bearings for the benefit of safety and cost. According to our proposal, the seismic isolators do not support vertical loads but they Just function as the period shifter and the horizontal damper. To verify this approach experimentally, the real scale bearings and lead rubber bearings far the real highway bridges were designed and fabricated. And the responses of this isolated bridges to the assumed earthquakes were determined by the pseudo dynamic test scheme. The test results were also compared to the responses computed by the well known structural analysis software to check the reliability of the test. From the test results, we found that the retrofitted bridges using the proposed method showed stable performances under earthquakes.


Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit | 2016

Determination of the optimal span length for a railway bridge crossed by various types of high-speed trains

Jeong-Rae Cho; Kilje Jung; Keunhee Cho; Jong-Won Kwark; Young-Jin Kim; Byung-Suk Kim

This paper proposes a method that can be used during the preliminary design stage to determine the optimal span length of a railway bridge that minimizes its dynamic responses to the passage of high-speed trains. Since the designed speed for passage over a railway bridge is generally higher than the speed at which the resonance phenomenon occurs, the peak dynamic responses of the bridge are likely to occur when a train travels across a bridge. Therefore, this study suggests inertia and elastic spectra that represent the inertial force and elastic force per unit length of the bridge at the resonance condition, respectively. These spectra are defined as functions of the span length of the bridge, for which the type of train and damping ratio are fixed, and based on the relationship between the dynamic responses of two different railway bridges that was used as theoretical basis for the design diagram proposed by the European Rail Research Institute. The optimal span length of the bridge that produces the smallest responses is determined using the suggested spectra by quantitatively comparing the responses at resonance under various train loads as a function of the span length of the bridge. The proposed method is validated using numerical examples that consider the computation of the optimal span length of a simply supported single-span bridge crossed by individual KTX, HEMU and ICE 2 trains and combinations of these trains.


MATEC Web of Conferences | 2015

Numerical Analysis on Variation of Dynamic Response of Girder Bridges with Torsional Reinforcement Panels

Jae-Yoon Kang; Jong-Won Kwark; Sung Yong Park; K.T. Kim

The dynamic flexural behaviour of the railway bridge is influenced by its torsional behaviour. Especially, in the case of girder railway bridges, the dynamic response tends to amplify when the natural frequency in flexure (1 st vibration mode) is close to that in torsion (2 nd vibration mode). In order to prevent such situation, it is necessary to adopt a flexural-to-torsional natural frequency ratio larger than 120%. This study proposes a solution shifting the natural frequency in torsion to high frequency range and restraining torsion by installing concrete panels on the bottom flange of the girder so as to prevent the superposition of the responses in the girder bridge. The applicability of this solution is examined by finite element analysis of the shift of the torsional natural frequency and change in the dynamic response according to the installation of the concrete panels. The analytical results for a 30 m-span girder railway bridge indicate that installing the concrete panels increases the natural frequency in torsion by restraining the torsional behaviour and reduces also the overall dynamic response. It is seen that the installation of 100 mm-thick concrete panels along a section of 4 m at both extremities of the girder can reduce the dynamic response by more than 30%.


Engineering | 2013

Load-Measuring Pot Bearing with Built-In Load Cell —Part I: Design and Performance

Jeong-Rae Cho; Young-Jin Kim; Jong-Won Kwark; Sung Yong Park; Won Jong Chin; Byung-Suk Kim


Journal of the Korean Society for Railway | 2010

Seismic Performance of Prefabricated Composite Column for Accelerated Bridge Construction

Jung Woo Lee; Won-Jong Chin; Chang-Bin Joh; Jong-Won Kwark


Journal of The Korean Society of Civil Engineers | 2003

Dynamic Behavior of Concrete Box Girder Bridge due to Riding Korean High-Speed Train

Jong-Won Kwark; Won-Jong Chin; Young-Jin Kim; Byung-Suk Kim


MATEC Web of Conferences | 2015

Application of Concrete Segment Panels for Reduction of Torsional Vibration Responses of Girder Bridges

Jong-Won Kwark; Jae-Yoon Kang; Sung Yong Park; Keun-Taek Kim

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Young-Jin Kim

Seoul National University

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E. J. Choi

Seoul National University

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Sung-Pil Chang

Seoul National University

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