• Steel and Composite Structures
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• v.22 no.5
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• pp.1019-1038
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• 2016

The use of high-strength concrete (HSC) in precast concrete segmental bridges (PCSBs) can minimize the superstructure geometry and reduce beam weight, which can accelerate the construction speed. Dry joints between the segments in PCSBs introduce discontinuity and require special attention in design and construction. Cracks in dry joints initiate more easily than those in epoxy joints in construction period or in service. Due to the higher rupture strength of HSC, the higher cracking resistance can be achieved. In this study, shear behavior of dry joints in PCSBs was investigated by experiments, especially focusing on cracking resistance and shear strength of HSC dry joints. It can be concluded that the use of HSC can improve the cracking resistance, shear strength, and ductility of monolithic, single-keyed and three-keyed specimens. The experimental results obtained from tests were compared with the AASHTO 2003 design provisions. The AASHTO 2003 provision underestimates the shear capacity of single-keyed dry joint C50 and C70 HSC specimens, underestimates the shear strength of three-keyed dry joint C70 HSC specimens, and overestimates the shear capacity of three-keyed dry joint C50 HSC specimens.

• Journal of the Korea Concrete Institute
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• v.23 no.2
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• pp.235-244
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• 2011

Failures of segmental bridges have been attributed to the inadequate joint connection techniques, which led to corrosion of the post-tensioned tendons connecting the segmental joints. The principal objective of this study is to evaluate the performances of the in-situ cast joint and epoxy applied shear key joints as a function of shear and ultimate strengths. Furthermore, shear behavior and strength of shear key joints in ultra high performance precasted concrete segmental bridges are experimentally evaluated to understand its shear failure behavior. The test parameters of shear key shape and type, load-displacement relations, cracking behavior, concrete strength, and fracture modes are considered in the study. Also, several parameters which influence the mechanical behavior of the shear key joint are analyzed. Based on the study results, the optimal shear key shape and joint type are proposed for the joint design and analysis guidelines.

• Magazine of the Korea Concrete Institute
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• v.10 no.1
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• pp.161-169
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• 1998

프리스트레스트 콘크리트 교량의 건설공법인 프리캐스트 세그멘탈 공법에서선형관리 기술은 핵심기술 중 하나이다. 그럼에도 불구하고 , 우리나라에서는 몇몇 교량기술자들에게 경험적으로 이해되고 있는 수준을 넘지 못하고 있다. 특히, 세그멘트의 제작에서부터 반드시 필요한 선형관리용 S/W 및 그 운용기술은 아직까지도 선진기술에 의존하고 있는 실정이다. 본 연구에서는 프리캐스트 세그멘탈 공법의 선형관리 기술에 대한 연구를 통하여 3차원적인 세그멘트 제작관리와 가설시 선형관리를 위한 제작선형을 자동적으로 계산할 수 있는 GEOCON을 개발하였다. 본 논문에서는 GEOCON의 알고리즘에 대하여 논하였으며, 특히 수치예제로서 제작오차의 발생위치에 따라 교량선형에 미치는 영향을 분석하였다.

• Proceedings of the Korea Concrete Institute Conference
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• 1994.04a
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• pp.42-46
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• 1994

본 연구에서는 프리캐스트 PC 세그멘탈 교량 접합부의 전단거동을 파악하기 위하여 전단키 접합부의 전단거동과 전단강도 특성을 실험적으로 연구하였다. 본 연구를 통하여 접합부 형상에 따른 하중-변위 관계, 균열거동, 파괴모드, 전단강도 등을 규명하고, 접합부의 역학적 거동에 영향을 미치는 여러인자들에 대해 분석한다. 또한 이로부터 최적의 접합부 형상을 도출하고, 이에 따른 최적의 접합방식을 검토함으로써 접합부 설계의 지침과 해석의 근거를 제시한다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1990.10a
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• pp.101-104
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• 1990

The program which could determine cross-sectional dimensions of the box girder bridge at tile stage of preliminary design was developed using the optimal technique in this study. It could minimize the cost and time required in the design of box girder bridges and the construction with the prestressed precast segmental method. Objective cost function consisted of four independent variables such as widths and depth of the cross-section. The Nelder-Mead method was used to solve the nonconstrained nonlinear problem like this.

• Journal of the Korean Professional Engineers Association
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• v.34 no.1
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• pp.23-26
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• 2001

Seohae Grand Bridge is a part of the new West Coast Highway(353km) under construction, which connects Inchon and Mokpo. It is the longest bridge in Korea (7.31 km), and has 97 spans of 60m each precast segmental approach bridges, 2 main spans of 165m each free cantilever segmental bridge(500m), and 1 stay cable bridge of 990m In total length. During the seven year long construction period, many new construction technologies and methods were utilized for the first time in Korea, and gave invaluable opportunities to experience and master these in completing the project on time with safety and precision. I am proud of being a member of this project, and wish to express deep appreciations to those who participated in the project.

• Magazine of the Korea Concrete Institute
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• v.10 no.2
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• pp.127-135
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• 1998

프리캐스트 세그멘탈 교량의 3차원적인 선형관리를 수행할 수 있는 S/W로서 GEOCON이 개발되었다. GEOCON은 기본적으로 제작장에서 세그멘트 제작관리를 통한 선형관리를 실시하고, 그 결과로서 자동적으로 계산되는 제작선형은 가설시 선형관리에 활용된다. 본 논문에서는 실제 현장에서 나타날 수 있는 검측오차등으로 인하여 수치계산상으로는 마치 정확한 선형관리가 이루어지는 것으로 나타날 수 있는 상황들을 방지하기 위해 GEOCON에서 채택하고 있는 기술적인 특징들에 대하여 논하고 있다. 또한 실제 현장적용을 통하여 GEOCON의 효용성을 검증하였다. GEOCON을 통하여 선형관리된 부산항 배후도로 현장은 총 길이 2109m의 프리캐스트 세그멘탈 교량구간을 포함하고 있으며 고임판의 사용없이 허용 관리치 내에서 매우 정확한 선형관리가 이루어졌다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.1
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• pp.71-81
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• 1994

A method is presented for the analysis of curved segmentally erected prestressed concrete box girder bridges including time-dependent effects due to load history, temperature history, creep, shrinkage, aging of concrete and relaxation of prestressing steel. The segments can be either precast or cast-in-place. Thin-walled beam theory and finite element method are combined to develop a curved nonprismatic thin-walled box beam element. The element consists of three nodes and each node has eight displacement degrees of freedom, including transverse distortion and longitudinal warping of the cross section.

• Journal of the Korea Concrete Institute
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• v.27 no.1
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• pp.55-63
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• 2015

Prefabrication technologies are making bridge construction safer and less disruptive to the environment and traveling public, making bridge designs more constructible and, improving the quality and durability by shifting site work to a more controllable environment. Modular bridge substructures with concrete-filled steel tube (CFT) piers and composite pier caps were suggested to realize accelerated bridge construction. The precast segmental pier cap consists of a composite pier table and precast prestressed segments on the table. The pier table has embedded steel section to mitigate stress concentration at the connection by small tubes. Each bridge pier has four or six CFT columns which connect to the pier cap. Shear strength of the pier cap was obtained by extending vertical reinforcing bars from the table to the precast segment. Transverse prestressing was introduced to control tensile stresses by service loadings. Structural performance of the proposed modular system was evaluated by static tests. Design requirements of the composite pier cap were satisfied by continuous reinforcing bars and prestressing tendons. Standardized modular substructures can be effectively utilized for the fast replacement or construction of bridges.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.5
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• pp.1-11
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• 1993

Precast/Prestressed concrete segmental bridges with moderate range of span length normally have a constant section height for economic segment manufacturing. Inside sectional dimension is often controlled for design of non-prismatic section between supports when variable stiffness is required. It is usual, in the preliminary design stage, to adopt trial bridge sections by past experience or by approximately estimated member forces. Three bridge models of different member stiffness have been selected to investigate flexural stiffness effects on member forces for preliminary design stage. The selected bridge stiffness has been determined by the flexibility index from review of the practically usable sections.