• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.2
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• pp.185-189
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• 2017

The purpose of earthquake resistant design for typical bridges is the 'No Collapse Design' allowing emergency vehicles just after earthquakes. The Roadway Bridge Design Code provides design provisions to carry out such 'No Collapse Design' with a ductile mechanism and response modification factors given for connections and substructure play key role in this procedure. In case of response modification factors for substructure, the Roadway Bridge Design Code provides values considering ductility and redundancy. On the other hand, 'AASHTO LRFD Bridge Design Specifications' provides values considering additionally an artificial factor according to the bridge importance categories divided into critical, essential and others. In this study, a typical bridge with steel bearing connections and reinforced concrete piers is selected and different response modification factors for substructure are applied with design conditions given in the Roadway Bridge Design Code. Based on the comparison study of the design results, supplementary measures are suggested required by applying different response modification factors for substructure.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.3
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• pp.283-288
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• 2011

For the earthquake resistance design designer should provide that structural yielding process is principally designed with the ductile failure mechanism. In order to get the ductile failure mechanism for typical bridges, pier columns yielding should occur before that of connections. However domestic bridge design with unnecessary stiff substructure leads to unnecessary seismic loads and makes it difficult to get the ductile failure mechanism. Such a problem arises from the situation that earthquake resistant design is not carried out in the preliminary design step. In this study a typical bridge is selected as an analysis bridge and design strengths for connections and pier columns are determined in the preliminary design step by carrying out earthquake resistant design. It is shown through this procedure that it is possible to get the ductile failure mechanism with structural members determined by other design.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.3A
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• pp.173-180
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• 2011

This paper aims to propose an image processing technique for measuring the static displacement of bridges from general inspection photograph; the color, shape, and spatial transformations of an arbitrary image stored in bridge management system database are used. This study is verified by using numerical analyses with experiments; the results demonstrate that the static displacement of bridges are measured by proposed technique. Moreover, this technique is able to obtain the static structural response of the bridge with changes in temperatures.

• Magazine of the Korea Institute for Structural Maintenance and Inspection
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• v.16 no.2
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• pp.74-86
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• 2012

이태리를 비롯한 대부분의 유럽 국가들에 건설된 많은 기존 도로 및 철도 교량들 중에는 현재의 구조설계기준이나 교통시스템, 유지관리비용 절감 등을 고려한 요구조건과 비교했을 때 구조적 안전성과 기능성을 만족시키지 못하는 경우가 종종 있다. 따라서 어떤 형식의 교량이든 특정 취약성을 평가할 수 있는 신속하고 신뢰성 있는 방법론이 필요하다. 이 논문의 앞부분은 이태리 내 도로 및 철도 구조물에 대해 그런 형태의 방법론의 적용에 대해 기술하였으며, 그 결과를 보면, 한 예로 조적조 아치 교량이 일반적으로 상당히 건전한 구조 시스템으로 나타났으며 RC 교량은 일반적으로 내구성 문제를 드러내며 지진하중에 대해서도 취약한 것으로 나타났다. 강교량은 내구성 문제 외에 피로에 특히 취약한 것으로 나타났다. 그리고 이 논문에서 고려한 전형적인 보강기법들에 대해 간략히 소개하였다. 뒷부분에서는 네 개의 기존 RC교량을 중심으로 주요 교량보강 사례연구들에 대해 좀 더 자세히 기술하였다. 이 교량들은 2차 세계대전 이후에 가장 일반적으로 채택되던 형식들 중의 한 예로 보강기법의 일반적 성질을 고찰하는데 있어 적합하다. 교량의 성능개선에 대해서는 방법론적 접근에 대해 개략적으로 나타내었으며, 여기에는 구조물의 유형적 특성, 유지관리 현황, 기능적 요구조건 및 보수 보강 시스템과 연계된 환경적인 면을 고려하고 있다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.28 no.2
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• pp.207-212
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• 2015

Bridges are designed and constructed as infrastructures in order to overcome topographical obstructions for fast and smooth transfer of human/material resources. Therefore the shape and size of piers constructed along the longitudinal bridge axis should be restricted by topographical conditions. Action forces of connections and piers are affected by pier shapes and sizes together with connection arrangement which decides load carrying path under earthquakes. In this study a typical bridge is modelled with steel bearings and reinforced concrete piers and seismic analyses are performed with analysis models with different arrangement of steel bearings and piers. From analysis results ductile failure mechanisms for all analysis models are checked based on strength/action force ratios of steel bearings and pier columns. In this way the influences of arrangement of connections and piers on the earthquake resistant capacity of typical bridges are figured out in view of forming ductile failure mechanism.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.3
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• pp.163-172
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• 2014

The purpose of earthquake resistant design for typical bridges is the No Collapse Design and the Earthquake Resistant Design Part of Roadway Bridge Design Code provides a design process to construct the Ductile Failure Mechanism for the bridge structure. However, if it is not practical to provide the Ductile Failure Mechanism due to structure types or site conditions, the Brittle Failure Mechanism is an alternative way to get the No Collapse Design. As well as the existing design process constructing the Ductile Failure Mechanism, the Earthquake Resistant Design Part provides a ductility-based design process as an appendix, which is prepared for bridges with reinforced concrete piers. According to the new design process, designer determines a required response modification factor for substructure and transverse reinforcement for confinement therefrom. In this study, a typical bridge with steel bearing connections and reinforced concrete piers is selected for which the existing as well as the ductility-based design processes are applied and different results from the two design processes are identified. Based on the results, an earthquake resistant design procedure is proposed in which designers should consider the two design processes.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.1
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• pp.49-57
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• 2013

Structural elements of typical bridges are superstructure, connections, substuctures and foundations and earthquake resistance is decided with the failure mechanism formed by substuctures and connections. Therefore earthquake resistant design should be carried out in the basic design step where design strengths, e.g. design sections for structural elements are determined. The Earthquake Resistant Design Part of Korean Roadway Bridge Design Code provides two basic design procedures. The first conventional procedure applies the Code-provided response modification factors. The second new procedure is the ductility-based earthquake resistant design, where designer can determine the response modification factors. In this study, basic designs including the two design processes are carried out for a typical bridge and supplements are identified in view of providing earthquake resistance.

• Journal of the Korean Society for Railway
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• v.15 no.2
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• pp.154-161
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• 2012

The damping ratio of railway bridge has become one of the most important issues in dynamic design and dynamic stability of railway bridge. In the present study, laboratory and field test were performed for railway bridges such as a twin I-shaped steel composite girder, PSC box, steel box, PSC, IPC, PRECOM, preflex. The damping ratio of railway bridge according to structure types was estimated by logarithmic decrement method. Therefore, magnitude, frequency and amplitude of load did not affect damping ratio of railway bridge. Also, damping ratio limit of steel composite and PSC bridges was evaluated in 1.0%.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.1
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• pp.1-11
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• 2013

In this study, in order to increase the span length, the temporary bridge which the center part of span is strengthened by small H-beam and the end part of span is strengthened by steel plate is designed and constructed. Real behavior of proposed temporary bridge is analyzed by field loading test. Analyzed shear buckling strengths and nonlinear behavior of suggested temporary bridge are compared with the those of general temporary bridge. From the field loading test results, it is analyzed that real static behavior of suggested temporary bridge is agree with the analyzed behavior which is considered in design process. Under the proposed design condition, it is investigated that the shear buckling strength of suggested temporary bridge is about 40% higher than that of general temporary bridge, and the ultimate strength of suggested temporary bridge is about higher than that of general temporary bridge. From the study results, it is concluded that the proposed temporary bridge can be applied by the needs of field condition.

• The Journal of the Korea Contents Association
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• v.14 no.7
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• pp.511-517
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• 2014

The superstructure type of the railway bridge in our country, is mainly classified into the box girder and the I-type girder. The box girder is widely used in the high speed railway bridge because of the safety due to dynamic behavior. The I-type girder is used in the conventional railway bridge, and is also divided into the general type and the composite type, and the newly modified types have been developed. According to the current railway bridge design code, the girder design by the span length in various railway bridge types are performed in this study. The suitable girder height by the span length are analyzed, and the comparative analysis of the structural efficiency and the economical efficiency is carried out. From this study, the composite type girder is appeared the good result in respect of the structural efficiency. However, in the economical aspect, the general I-type girder is required less cost than the other types.