• Journal of the Korea institute for structural maintenance and inspection
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• v.6 no.2
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• pp.211-216
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• 2002

A steel plate-concrete composite slab with pyramidal shear connectors, named TSC composite slab, is expected to have sufficient bending strength and flexural rigidity for loads during and after construction. Fatigue problems play an important role in designing composite slab as bridge decks under traffic conditions. In this paper, a series of fatigue tests was carried out on TSC beam specimens under various loading conditions, in order to evaluate the fatigue strength of TSC composite slabs. The results are as follows : (1) the fatigue failure of TSC composite beams results from the tensile fracture of bottom steel plate and shear connector, and (2) fatigue strength of the steel plate for two million cycles can be estimated to be $1144kgf/cm^2$ from the S-N curves.

• Journal of the Korean Society of Safety
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• v.24 no.6
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• pp.93-102
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• 2009

Because steel girder bridge has big slenderness ratio, buckling is very important in design. Local buckling of plate girders having two longitudinal stiffeners in different positions under various load conditions is investigated. Various parametric study according to the change of web height, transverse stiffeners and load conditions are examined. These parametric studies are performed by numerical simulation utilizing finite element method. The objective of this study is to present the rational reinforcement location of two longitudinal stiffeners. The results of analysis are compared to that recommended by korean specifications for road bridges(2003).

• Proceedings of the KSR Conference
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• 2000.05a
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• pp.511-518
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• 2000

The high speed train service will be offered for high-quality transport service in existing railway by Korean National Railroad(KNR). Therefore, this paper presents the results of analysis carried out to determine the dynamic response characteristics of deck plate girder bridges which are representative elevated structures of existing railway and to evaluate their suitabilities for supporting Korea Train Express(KTX) trainsets in the speed range 0-250 km/h. Their dynamic characteristics are analyzed concerning structural safety, train-operation safety and passenger comfort. The simplified method for 2-dimensional train/track/bridge interaction analysis is utilized in the analysis of dynamic behaviors of deck plate girder bridges.

• Advances in materials Research
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• v.5 no.2
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• pp.81-92
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• 2016

Stress concentration is an interesting and essential field of study, as it is the prime cause of failure of structural parts under static load. In the current paper, stress and strain concentration factors in unidirectional functionally graded (UDFGM) plate with central circular cutout are predicted by carrying out a finite element study on ANSYS APDL platform. The present study aims to bridge the lacuna in the understandings of stress analysis in perforated functionally graded plates. It is found that the material variation parameter is an important criterion while designing a perforated UDFGM plate. By selecting a proper material variation parameter and direction of material gradation, the stress and strain concentrations can be significantly reduced.

• International Journal of Highway Engineering
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• v.10 no.1
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• pp.11-18
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• 2008

The behavior of pavement and waterproofing layer on the steel bridge deck system under traffic loading was analyzed using a finite element method in this paper. In the finite element analysis, the othotropic steel bridge deck is represented by equivalent plate using solid element instead of shell element and the interface is assumed perfect bonding state. The effects of several parameters such as thickness of deck, Young's modulus of deck, thickness of pavement, different braking loading, and temperature on the stresses and strain in the interface are investigated for bridge deck pavement. The shear stress of waterproof layer increases with decrease of bridge deck thickness and stiffness. The change of shear stress is negligible when the bridge deck thictaess is greater than 150mm and stiffness is greater than $2{\times}10^{5}MPa$. As the pavement thickness and temperature decrease, the shear stress in the waterproof layer tends to be increased. The tensile strain at the bottom asphalt layer decreases as the temperature and thickness increase.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.1
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• pp.67-73
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• 2017

This study has addressed to evaluate the effects of radius of curvature and skew angle on the negative reaction in a plate girder bridge with LRB (Lead Rubber Bearing) supports. As analytical parameters, various radius of curvatures and skew angles were selected and two seismic loads of El-Centro and artificial earthquakes were applied to the bridge in the longitudinal and transverse directions. As results of 3D analysis, the possibility of negative reaction is shown at the part of acute angle and inner side of the curved bridge, and becomes increased when seismic load is applied in the transverse direction. In addition, the occurrence of negative reaction is found to be increased as both radius of curvature and skew angle decrease, which means that curved bridge has higher possibility of negative reaction than straight one. Conclusively, all of earthquake wave, gradient, radius of curvature and skew angle should be considered together to investigate the possibility of negative reaction at the bridge support subject to seismic load.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.2
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• pp.287-296
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• 2019

In recent years, a number of long span cable-stayed pedestrian bridges have been constructed to the advantages of relatively low cost construction and the many tourists visiting. However, most of the pedestrian bridges are located in parks or sightseeing areas, so they are conducted without proper review and design process. It is necessary to review the aerodynamic stability of the long span cable-stayed pedestrian bridge, and it should be designed in detail from various points of view rather than the road bridge. In this study, we investigated the wind characteristics of the cable-stayed pedestrian bridge, and the empirical equations for the relationship between the main span length and the fundamental natural frequencies are presented for future use. In addition, the flutter wind speed limit of the flat plate deck pedestrian bridge calculated using the Selberg's equation is also presented. The final aerodynamic bridge section which satisfied the aerodynamic stability was found from open grating method. The proposed method can be used for long span cable-stayed pedestrian bridge in the future.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.707-716
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• 2011

It has been applied using cranes or insertion methods to install heavy structures to strengthen existing railway bridges. These methods are uneconomical because of two reasons. The first one is it is required to construct approach roads for heavy equipment and/or working yard. The second one is the electric lines shall be cutoff during construction. Both require additional construction cost and duration. In this study, new transport equipment was developed which can be applied to heavy structures up to 100 ton. Using this method, the heavy structure can be loaded into the new transport equipment at working yard and transported to the working site. This method can be applied, but not limited to railway bridge or roadbed rehabilitation. It was found that the precious construction can be achieved to install heavy structure using this method. The experimental construction to make non-ballast girder bridge composite with new pc deck slab using this method was carried out for Jewon bridge. The example bridge is in extreme condition because it locates above national road #38 within extreme transition curve and has 10 ‰ slope and skew. The experimental construction results were satisfactory both for safety and construction precision.

• Steel and Composite Structures
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• v.36 no.4
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• pp.463-480
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• 2020

Although detailed shell analysis is suitable to predict the ductile crack initiation life of steel members, such detailed method adds time expense and complexity. In order to simply predict the ductile crack initiation life of stiffened steel bridge piers, a total of 33 cases are simulated to carry out the parametric analyses. In the analysis, the effects of the width-to-thickness ratio, slenderness ratio, plate thickness and so on are considered. Both shell analyses and beam analyses about these 33 cases are conducted. The plastic strain and damage index obtained from shell and beam analyses are compared. The modified factor β_s is determined based on the predicted results obtained from both shell and beam analyses in order to simulate the strain concentration at the base corner of the steel bridge piers. Finally, three experimental results are employed to verify the validity of the proposed method in this study.

• Structural Engineering and Mechanics
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• v.27 no.6
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• pp.651-670
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• 2007

An experimental study to evaluate a redundancy capacity in simple span two plate-girder bridges, which are generally classified as a non-redundant load path structure, has been performed under the condition that one of the two girders is seriously damaged. The bottom lateral bracing was selected as an experimental parameter and two 1/5-scale bridge specimens with and without bottom lateral bracing have been prepared. The loading tests were first performed on the intact specimens without cracked girder within elastic range. Thereafter, the ultimate loading tests were conducted on the damaged specimens with an induced crack at the center of a girder. The test results showed that the cross beams and concrete deck redistributed partly the applied load to the uncracked girder, but the lateral bracing system played a significant role of the load redistribution when a girder was damaged. The redundancy was evaluated based on the test results and an appropriate redundancy level was evaluated when the lateral bracing was provided in a seriously damaged simple span two-girder steel bridge.