• Composites Research
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• v.12 no.4
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• pp.25-32
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• 1999

A method of calculating the natural frequency corresponding to the first mode of vibration of beams and tower structures, with irregular cross sections and with arbitrary boundary conditions was developed and reported by Kim, D. H. in 1974. In this paper, the result of application of this method to the special orthotropic plates on elastic foundation with free boundaries is presented. Such plates represent the concrete highway slab and hybrid composite pavement on bridges. Any method may be used to obtain the deflection influence surfaces needed for this vibration analysis. Finite difference method is used for this purpose, in this paper. The influence of the modulus of the foundation and the aspect ratio of the plate on the natural frequency is thoroughly studied. The effect of neglecting the mass of the plates on the natural frequency, as the ratio of the point mass/masses to the plate mass increases, is also studied, in deep.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1149-1155
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• 2007

The transition area between a bridge and an earthwork is one of the weakest area of track because of the track geometry deterioration caused unequal settlement of backfill of abutment. In case of a ballastless track, the approach slab is installed to prevent the phenomenon. But, if there is occurred the inclined displacement on the approach slab by a settlement of the foundation or formation, the track is also under the inclined displacement. And this defect causes reducing the running stability of a vehicle, the riding comfort of passengers, and the deteriorations of track by excessive impact subjected to the track. In this study, parametric studies were performed to know what is the allowable displacement limit on the approach slab to avoid such a bad effect. The length and amount of unequal settlement of the approach slab was adopted as parameter for numerical analysis. And car body accelerations, variations of wheel force and rail stress and uplift force induced on a fastener clip are investigated. From the result, resonable settlement limits of an approach slab according to slab length was suggested.

• Journal of Korean Society of Steel Construction
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• v.12 no.4 s.47
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• pp.407-416
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• 2000

This paper presents the dynamical responses of the plate girder bridge subjected to moving load by experimental method. The upper slab of the plate girder bridges is modelled to the plate element and the girder to the beam element. The small-scaled vehicle model is manufactured as moving load and the acryl-bridge model as the plate-girder bridge. The dynamic responses of the plate-girder bridges under the moving load are obtained by the strain gauges, displacement measurements, accelerometer, and dynamic strain measurement. The maximum dynamic responses from the measured data are compared with those from the finite element method. The experimental model test can be used to obtain to the dynamic responses of the plate-girder bridges.

• Journal of the Society of Disaster Information
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• v.10 no.1
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• pp.61-70
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• 2014

Synthetic fiber reinforced concrete is applicable to many applications for construction material. In general, synthetic fibers have low tensile strength and elastic modulus, but they have many advantages such as high crack resistance, impact resistance, chemical resistance, flexural behavior and corrosion free in fiber reinforced concrete. Recently, fiber reinforced concrete with macro synthetic fibers has been used to improve performance of structures in tunnel shotcrete, precast segmental lining and bridge slab and precast concrete structures. This study investigated the influence of bundled type polyamide fiber reinforced concrete on the flexural behavior in accordance with ASTM C 1609 and KS F 2566 standards.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.20-27
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• 2009

This paper presents an analytic study for replacement of the ballast track in existing subway bridge by the Precast slab panel(B2S) track. To evaluate the dynamic responses on application of B2S track, the time history analysis with the 3D modeling. A total of two models, which were one ballast track bridge and B2S track bridge, were used in the FE analysis. The results of this study show that the dynamic displacement and acceleration of the B2S track bridge were significantly reduced for a higher train speed, compared to the ballast track bridge. Also, the replacement of the ballast track bridge in existing subway bridge by the B2S track increased the structural safety of bridge and ensured sufficient dynamic stability and serviceability. As a result, the servicing subway bridge with B2S track system has need of the reasonable measures which could be reducing the static and dynamic response and improving the performance.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.28 no.1
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• pp.7-12
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• 2016

In this study, a simplified collision model of pile protective structures against a navigation vessel was proposed and verified. The model of pile protective structure were composed by two plastic hinges at below of cap slab and the inside of ground. A nonlinear equation of motions was developed in consideration of the kinematic energy, potential energy and deformation energy in collision event. The developed simplified model were verified by the precise finite element collision analysis of the vessel and the protective structure.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.13 no.1
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• pp.25-35
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• 2000

The superstructure of general bridge like slab bridge and slab on girder bridge is composed of elastically supported isotropic plate. The objective of this study is to develop the new analysis method for elastically supported plate with general edge beam or girder(boundaries) under arbitrary out of plane loading. The displacement solutions for the macro-element of plate and beam are obtained by solving for the unknown interactive forces and moments at the beam or nodal line locations after satisfying equilibrium equation along the nodal line. The displacement functions for macro-elements ate proposed in single Fourier series using harmonic analysis, and the equilibrium equations of nodal line are composed by using slope-deflection method. The proposed analysis method is programmed by MS-Fortran and can be applied to all types of isotropic decks with bridge-type boundaries. Numerical examples involving elastically supported plates with various aspect ratio, loading cases, and bridge-type boundary conditions are presented to demonstrate the accuracy of this program. The major advantage of this new analysis method is the development of a simple solution algorithm, leads to obtain rapidly responses of bridge deck system. This proposed method can be used in parametric study of behavior of bridge decks.

• Journal of Korean Society of Disaster and Security
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• v.15 no.3
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• pp.67-77
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• 2022

In South Korea, U-type girder development was attempted as a means to increase the length of I-type girder, but due to the large self-weight according to the post-tension method, the application of rail bridges of 30m or less is typical. There are not many examples of application of pre-tension type girder. This study does not limit the post-tension method, but applies the pre-tension method to induce a reduction in self-weight and materials used due to the reduction of the cross-section. In addition, we intend to apply the on-site pre-tensioning method using the internal reaction arm of the U-type girder. The prestressed concrete U-type girder bridge is composed of a concrete deck slab and a composite section. Compared to the PSC I-type, which is an open cross-section because the cross section is closed, structural performance such as resistance and rigidity is improved, the safety of construction is increased during the manufacturing and erection stage, and the height ratio is reduced due to the reduction of its own weight. Therefore, it is possible to secure the aesthetic scenery and economical of the bridge. As a result, it is expected that efficient construction will be possible with high-quality factory-manufactured members and cast-in-place members. In this paper, the introduction of the pre-tension method on-site and the analytical performance verification of the anchoring block for tension are included.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.8
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• pp.545-551
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• 2018

For domestic application of the temperature gradient model proposed by foreign design standards, a specimen of steel box girder bridge was fabricated with the following dimensions: 2.0 m width, 2.0 m height and 3.0 m length. Temperature was measured using 24 temperature gauges during the summer of 2016. The reliability of the measured data was verified by comparing the measured air temperature with the ambient air temperature of the Korea Meteorological Administration. Of the measured gauges, four temperature gauges that can be compared with the temperature difference of the Euro code were selected and used to analyze the distribution of the measured temperatures at each point. The reference atmospheric temperature for the selection of the maximum temperature difference was determined by considering the standard error. Maximum and minimum temperatures were calculated from the four selected points and the resulting temperature difference was calculated. The model for the temperature difference in the steel box girder bridge was shown by graphing the temperature difference. Compared to the temperature distribution of the Euro code, the presented temperature difference model showed a temperature difference of $0.9^{\circ}C$ at the top and of $0.3^{\circ}$ to $0.4^{\circ}C$ at the intermediate part. These results suggested that the presented model could be considered relatively similar to the Euro code The calculated standard error coefficient was 2.71 to 2.84 times the standard error and represents a range of values. The proposed temperature difference model may be used to generate basic data for calculating the temperature difference in temperature load design.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.740-745
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• 2020

To calculate the reasonable design temperature load of a concrete box girder bridge, one bridge test specimen was made. The temperature gauges installed on the bridge test specimen measured 48 sets of temperature per day at 30-minute intervals during the summer and winter periods of one year. The temperature measured at each station was treated statistically to calculate the trend line and standard error, and the temperature distribution and trend line at the representative station were presented. The maximum effective temperature and the lowest effective temperature were calculated from the air temperature suggested by Euro code. The maximum effective temperature was calculated to be 1.5 to 2℃ higher than the Euro code at 35℃ and above. In comparison, the lowest effective temperature was 0.5 to 1.1℃ lower at -13℃ to-19℃. Compared to the effective temperature of this study according to the highest and lowest 50-year frequency of the Yangsan region, the highest effective temperature was 4.7℃ higher, and the lowest effective temperature was 4.5℃ lower. Considering the increasing climate change and reflecting the results of this analysis, it is deemed necessary to make the current temperature design standards larger.