• Proceedings of the KSR Conference
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• 2007.05a
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• pp.448-455
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• 2007

In 1992, the first design standard of quake proof bridge was established. However, most bridge structures which were constructed without considering earthquake in former times need performance of quakeproof property. Quakeproof analysis in current bridges, is based on analysis of load base which just has strength over the load of simple structures but is not checked through simple comparison of strength performance of structures so that we would like to check that ADRS method is reasonable or not using ADRS method(Accleration-Displacement Response Spectrum Method), a analysis method based on displacement of object of performance test. As the result of that, the capacity spectrum method can avoid complex dynamic analysis in analysis based on loads and it efficiently applies to design verification with normal checking for quakeproof performance and aimed performance of new structures. However we can not consider effects of high modes and it has problem that does not consider falling of performance in structures by repeated load.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.4
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• pp.101-111
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• 2013

In this study, DEA (Data Envelopment Analysis) was carried out on the four bridges, which have the same extension (L=1,615m), in order to select the most superior, economical method of construction using the LCC concept of each bridge structure in the case of the Ulsan-Pohang double track railway which is scheduled to be constructed. DEA models were analyzed with the CCR model, which was designed for the evaluation of relative efficiency of each model. The initial construction costs, maintenance costs, indirect costs (user costs + indirect loss of social costs), and life cycle costs were used as input variables, and average duration was applied as the output variable. LCC was applied to calculate the input variables, and to get the costs of LCC, 100 years of period and 4.83% of real discount rate were applied, and the costs are classified into initial construction, maintenance, user, and indirect loss of social cost. The analysis results showed that the Method 2 and 3 were evaluated as the most efficient, and the other alternatives were evaluated as the following order; Method 1, the default, and Method 4.

• Journal of Environmental Impact Assessment
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• v.26 no.1
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• pp.11-26
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• 2017

Approximate empirical equations obtained by measuring overall noise levels at different distances have been used to evaluate environmental influence of the railway noise though the accurate prediction of noise levels is important. In this paper, a noise prediction model considering the frequency characteristics of noise sources and propagation was suggested to improve the accuracy of noise prediction. The railway noise source was assorted into track, wheel, traction and aerodynamic components and they were characterized with the source strength and speed coefficient at each octave-band frequency. Correction terms for the acoustic roughness and the track/bridge condition were introduced. The sound attenuation from a source to a receiver was calculated taking account of the geometrical divergence, atmospheric absorption, ground effect, diffraction at obstacles and directivity of source by applying ISO 9613-2. For obtaining the source strength and speed coefficients, the results of rolling noise model, numerical analysis and measurements of pass-by noise were analyzed. We compared the predicted and measured noise levels in various vehicles and tracks, and verified the accuracy of the present model. It is found that the present model gives less error than the conventional one, so that it can be applied to make the accurate prediction of railway noise effect and establish its countermeasures efficiently.

• Journal of the Korea Concrete Institute
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• v.28 no.5
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• pp.545-553
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• 2016

This paper presents experimental static test results of the precast concrete panels developed for short-span concrete bridge deck form. Different from LB-DECK, concrete rib attached to the bottom surface of concrete panel, and Top-bar is not used at the top surface of concrete panel. Number of concrete ribs and cross-section details of concrete rib are determined from the analytical results of parametric study considering the span length and the thickness of concrete bridge decks. Shear rebars are installed at the top surface of concrete panel for composite action between precast concrete panel and cast-in-place concrete. In order to evaluate the safety and the serviceability of the developed short-span concrete panel subjected to design load, static load test is conducted. Three test panels with span length of 1.6m are fabricated, and during the load test displacements, strains and cracks of test panels are measured and final failure modes are investigated. Serviceability of the test panels is evaluated based on the results of displacements, cracking load, and crack width at the design load level. Safety is also evaluated based on the comparison of the ultimate strength and the factored design load of test panels. Based on the test results, it is confirmed the short-span precast concrete panel satisfies the serviceability and safety regulated in design codes. In addition, the range of span length of concrete bridge decks for the short-span concrete panel is discussed.

• Journal of Korean Society of Steel Construction
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• v.18 no.6
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• pp.747-758
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• 2006

With the growth of economy, the esthetic values of bridges become significant points in the decision process of a type of new bridges. So, it is common that a long-span bridge or a multi-purpose bridge are selected as the type of new bridges. Also, the economic growth derives increase in traffic and then the increased traffic derives multi purpose bridges from the decision process of bridge types. In the multi-purpose bridges with private fund, the construction cost is simply alloted to several organizations according to the percentage of participation and usage. But the allotment of the maintenance cost is not simple. Because the loads and safety factors in design are different between the criterion of design of highway bridges and that of railway bridges. In this study, we verify the possible problems in case of allotment method of maintenance cost in foreign examples as well as domestic example. As one of the method of determination of allotment ratio in maintenance cost, the method based on the stress of structural analysis is presented and it can be an example in the similar problem later.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.973-978
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• 2011

In this study, effects due to differences of creep and shrinkage which is caused by material differences such as concrete characteristic and age in an asymmetric PSC box girder were evaluated. For this purpose the prestress distribution, creep and shrinkage were analyzed with the FE analysis program, LUSAS 14.3. As a result of the prestress, the stress distribution was stable. In case of the analysis result which was conducted with 1,000 days response time, the shear stress between PC section and CIP section is satisfied with design shear strength.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.1
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• pp.82-87
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• 2010

A measurement system of contact force between overhead contact line and pantograph of train is developed which measures the contact force by using four sets of full-bridge strain gauges instead of load cells and accelerometers. The sensors are installed on the pan head of pantograph and the measured data from the sensors are transmitted to a server system in the train by way of wireless Lan. This configuration of the measuring system makes it easy to install on the trains without any alteration of train system. The measurement system is applied to KTX on the Kyungbu high speed line, and the measured contact force data shows good agreement with those measured by load cell and accelerometers. The waveform of the contact force between overhead contact line and pantograph contains essential information about their conditions. The proposed measurement system can probe any defects on overhead contact lines with train running at high speed, which will be a powerful solution for the maintenance of long-distance overhead contact lines.

• Journal of Power Electronics
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• v.18 no.4
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• pp.1140-1153
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• 2018

The harmonic impedance characteristic of a traction power supply system (TPSS) is necessary for taking actions to suppress the high-order harmonic resonances caused by AC electric locomotives. This paper proposes a controllable harmonic generating method (CHGM) for measuring the TPSS harmonic impedance by injecting harmonic disturbances of different frequencies and amplitudes into the TPSS. This method applies phase shifted pulse-width modulation (PSPWM) and ensures that the undesired sideband harmonics can be negligible while the desired harmonic is both controllable and adjustable. Multiple harmonics can be emitted at the same time. The implementation of the method is also presented. Simulations are carried out to validate the performance of the proposed method. Finally, experimental results on a 5 H-bridge converters platform verified the effectiveness and feasibility of the proposed method.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.608-612
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• 2004

Safety from derailment has been evaluated according to the magnitude of the derailment coefficient, which does not always ensure sufficient safety evaluation, and is not necessarily helpful in clarifying the mechanism of derailment. When wheel rolls, point of contact between wheel and rail was change continuously and flange touches with rail. Established gauge so that can measure location of contact point between wheel and rail by strain gauge. Also, wish to describe result that compose bridge circuit and execute load test.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.159-164
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• 2004

Recently the unexpected damage is broken out by the unusal change of weather. Misfortune on top of misfortune the typhoon did great damage again before finishing the repair work. And then we should study about the repair work of fast and safety as well as the construction of safety. The paper suggests the case study of a fast disaster restoration work. To minimise the term of repair work which selects Fast Track Method. This work is processed as follows. Temporary resortation is progressed at the same time as the main resortation. And In this paper, technique to evaluate the capacity of bridge is tried to develop by means of FEM analysis.