• Journal of Korean Society of Steel Construction
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• v.23 no.6
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• pp.691-704
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• 2011

This paper presents an investigation on the ultimate behavior of steel cable-stayed bridges in the construction stage, considering various geometric nonlinearities and material nonlinearities. To numerically determine the state of cable-stayed bridges in the construction stage, initial shape analysis and construction stage analysis via backward process analysis were done sequentially. Then nonlinear analysis of the state under the construction load condition, considering the weight of the derrick crane and the key segment of the girder loaded onto the tip of the center span, was performed to investigate the ultimate behavior of the structure. The effects of the girder-mast stiffness ratio, the cable-arrangement types, and the area of the stay cables on the ultimate behavior were also extensively investigated. Moreover, the results of the ultimate analysis, considering both geometric nonlinearities and material nonlinearities, were compared with the results of the geometric nonlinear analysis, for a more meaningful investigation of the ultimate behavior of steel cable-stayed bridges in the construction stage.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.6
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• pp.1309-1317
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• 1994

Because the stiffening girders are constructed after the installation of hangers for typical suspension bridge, no additional tensioning to hangers in construction is necessary for this bridge type in which main cable is earth-anchored. However, for self-anchored suspension bridge, hangers are installed after temporarily supporting stiffening girders constructed in previous stage. Therefore, initial tension is required on installing hangers. Tension of hangers varies as the construction proceeds. Hence, it is necessary to determine the most efficient method of installing hangers among several methods. This study presents finite element procedures and the algorithms of construction stage analysis to simulate construction processes. Geometric nonlinear analysis scheme is also included. The most effective method regarding the installation of hangers is presented through the examples of actual bridge model.

• Computational Structural Engineering
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• v.7 no.4
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• pp.10-16
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• 1994

근본적으로 터널을 정확히 해석하려면 3차원 해석이 필요하다. 그러나 3차원 해석은 다루어야 할 자료가 방대하고 또한 시공 단계를 고려하는 3차원 소성해석을 정확히 하기 위해서는 슈퍼컴퓨터와 같은 컴퓨터 파워가 요구된다. 따라서 터널의 해석에서는 대개 하중분배율법을 사용하여 2차원 해석을 수행하고 있는 실정이다. 그러나 하중분배율법에 의한 2차원 해석의 결과는 선택한 하중분배율법에 의존함으로 정확한 하중분배율을 아는 것이 중요하다. 2차원 터널해석을 정확히 하기 위해서는 본문에 기술한 요건을 갖춘 프로그램의 확보, 하중분배율에 대한 정확한 평가, 측압 계수의 신중한 선택, 주위 지반의 물성에 대한 신중한 평가가 필요하다.

• Computational Structural Engineering
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• v.9 no.4
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• pp.199-207
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• 1996

In the past decade soft clay shield tunneling technology have been improved to permit continuous support to the face of a tunnel. These advanced shield can be operated such that an initial heaving is created, this helps to decrease the inward soil movement into the tail void. In this paper, the measurement of slurry shield and EPB shield were used and two dimensional elasto-plastic programs EPSHILD developed for shield tunnel analysis were approved. The excavation steps corresponding with construction stages were settled and heaving load, load factors were considered. This study is based on the instantaneous settlement which is occured in the process of shield construction but not the secondary settlement by consolidation.

• Geotechnical Engineering
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• v.14 no.6
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• pp.81-92
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• 1998

A beam on elasto-plastic foundation modeling of soldier pile and woodlagging tieback walls or anchored walls was developed and tested. An instrumented full scale tieback wall in sand was constructed at the National Geotechnical Experimentation Bite located on Texas A&M University. The experimental earth pressure deflection relationship (p-y curves) was developed from the measurements. The construction sequence was simulated in the proposed method. The conceptual methodology of an anchored wall design was introduced by using the proposed method. The proposed method was evaluated with the measurements of case histories in sand and clay. A parametric research was performed to study the most influencing factors for the proposed method. It is concluded that the proposed method represents a significant improvement on the prediction of bending moments and deflections of the properly designed walls.

• Tunnel and Underground Space
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• v.34 no.3
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• pp.196-207
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• 2024

In this study, a comprehensive management plan was proposed to ensure the stability of the existing subway when constructing ground structures adjacent to the subway. In the first step, the measurement inspection cycle is selected through proximity evaluation, in the second step, the stability of existing subway and station structures such as displacement and stress is reviewed through 3D numerical analysis considering the construction stage and groundwater influence, and in the third stage, the safety of train operation was reviewed by examining the track stability, and based on the numerical analysis results in the fourth stage, the displacement concentration section was selected as an intensive management section and it was proposed that intensive measurement management be performed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.10 no.2
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• pp.49-58
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• 1990

A numerical procedure is developed to analyze the time-dependent deflections of prestressed concrete bridges constructed by the segmental cantilever method. The developed computer program accounts for the time-dependent properties of prestressed concrete materials due to the varying modulus of elasticity, creep and shrinkage of concrete and the stress relaxation of prestressing steel. It also accounts for the stiffness increase due to the presence of the steel reinforcements and the effects of the shear deformation of the prestressed concrete bridge girders. The program is applied to a multi-span continuous segmental prestressed concrete bridge to demonstrate its capabilities and to explore the behavior characteristics of the segmental bridges.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.194-201
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• 2003

대공간 구조시스템은 일반적으로 자중을 최소화하고 부재내력의 효과적인 사용이 매우중요하다. 따라서 준공후의 외력에 대한 구조적 거동에 대한 파악도 중요하지만 시공중의 거동에 대한 파악도 매우 중요하다. 특히 케이블 막구조의 경우 시각초기에 구조물이 불안정하지만 케이블에 장력이 도입되면서 점차적으로 구조물의 강성이 높아져 구조물이 안정화를 이루게 피므로 시공과정 해석 즉 안정화 이행과정해석이 시공계획을 설정하는 부분에서 매우 중요한 요소가 된다. 본고에서는 케이블 막구조의 실례로써 최근 완공된 인천문학 경기장 지붕구조를 대상으로 시공과정과 안정화 이행과정해석에 대한 소개를 한다. 인천문학경기장 지붕구조는 케이블에 장력을 도입하는 과정에서 발생되는 변형과 내력을 흡수하고 하부구조에 대한 영향을 최소화하기 위하여 마스크 지점의 회전과 이동이 가능한 특수공법을 채택하였으며 시공과정해석(안정화이행과정해석)을 통하여 제시된 단계별 목표장력 및 변위에 따라 시공과정이 계획되고 제어되었다. 특히 외국의 기술로 설계된 자료를 근거로 일방적으로 공사를 수행한 다른 구조물과는 다르게 국내의 기술력에 바탕한 구조 해석 등을 통하여 검증하여 최종 시공방법을 결정하였고 이러한 과정을 통하여 대공간 구조에 대한 기술력을 확보하고 확인할 수 있었으며, 그 결과 향후에는 국내의 기술력으로 이와 같은 대규모의 케이블 막구조의 설계와 시공이 가능할 것이라고 판단된다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.11
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• pp.6898-6905
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• 2014

A stress ribbon bridge is a PSC structure that behaves as a reverse arch structure due to post-tensioned thin deck of the catenary type. In foreign countries, the stress ribbon bridge is recognized as the minimum destruction of nature and beautiful bridge, and has many construction examples as pedestrian and car bridges. On the other hand, there have been few studies in Korea. In this study, the FE Analysis model was established for different construction stages considering the nonlinear and time-dependent behaviors. The FE model was verified by a comparison with the numerical results and the behavior was analyzed for the different construction stages.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.33 no.2
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• pp.137-144
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• 2020

In this study, we propose a new truss deckplate system, which does not require temporary floor supports during construction, with ultra-high-performance concrete (UHPC) infilled top bars. The increased stiffness and strength of the proposed system were well retained as compared to those of the existing truss deckplate systems, thereby resulting in the reduction of maximum deflection at the span center. Four-point bending tests were performed on five specimens with a net span of 4.6 m to evaluate the structural performance of proposed system in the construction stage. In addition, the load-deflection curve was plotted for each specimen, and the effects of test parameters were analyzed. Further, a rigorous nonlinear three-dimensional finite element analysis was performed, and its results were compared with the test results. From the results, it was observed that the test specimens of the proposed system exhibited superior performance as compared to those of the existing one and also satisfied the serviceability requirement during construction provided by the Korea Building Code 2016.