• Journal of the Korean Geotechnical Society
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• v.17 no.4
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• pp.269-278
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• 2001

국내 30개의 교대측방이동 사례현장에 대하여 교대기초말뚝의 사면안정효과와 교대의 실측측방변위를 고려한 사면안정해석을 실시하였다. 해석결과 사면안전율은 말뚝의 효과를 무시한 경우 1.5이상, 말뚤의 효과를 고려한 경우 1.8이상 되어야 안전함을 알 수 있다. 그리고, 교대의 실측측방변위와 사면안전율과의 상관관계로부터 교대의 허용측방변위 설계기준은 5cm보다 1.5cm로 함이 더 합리적임을 알 수 있다. 사면안정해석결과와 교대의 실측측방변위를 토대로 기존에 제안된 교대측방이동 판정기준의 국내 적용여부를 검토한다. 이를 위하여 교대의 사면안정해석결과 및 실측측방변위와 교대측방이동 관련지수와의 상관관계를 조사한다. 그 결과 실측된 교대의 측방변위와 이를 고려한 사면안전율은 교대의 측방유동지수, 측방이동판정지수 및 지반의 안정계수와 무관한 경우도 많이 존재하는 것으로 나타났다. 이는 결국 이들 경험적인 지수만으로 교대측방이동을 판정하는 것은 불충분함을 의미한다. 따라서, 교대측방이동을 판정할 경우에는 반드시 교대의 측방변위를 고려한 사면안정해석이 실시되어야 한다.

• Journal of the Korean Geotechnical Society
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• v.17 no.4
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• pp.199-208
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• 2001

본 연구의 목적은 교대가 설치된 지반의 사면안전율과 교대측방변위의 관계를 분석하여 교대의 측방이동 판정기준을 마련하고자 함에 있다. 이를 위하여 국내의 연약지반에 설치된 30개 교대의 측방이동사례를 조사하고, SLOPILE (Ver 2.0)프로그램을 이용하여 교대의 측방변위와 교대기초말뚝의 사면안정효과를 고려한 사면안정해석을 실시한다. 해석결과 교대기초말뚝의 실측측방변위를 고려할 경우 1.8이상 되어야 한다. 또한, 교대기초말뚝의 허용측방변위량에 따른 사면안정 해석결과, 교대의 허용측방변위가 작게 규정될수록 사면안정성에 기여하는 말뚝의 효과는 감소하고 있음을 알 수 있다.

• Journal of the Korean GEO-environmental Society
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• v.9 no.7
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• pp.13-23
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• 2008

In this study, the centrifuge tests and numerical analyses were performed to investigate the lateral flow behavior and stability of abutment when high filling was applied on the soft ground improved by SCP. The centrifuge model tests and numerical analyses were fulfilled in the case of the back of abutment filled by EPS (case 1) and soil (case 2), and the potentiometer was installed on the abutment and fill to measure the vertical and horizontal displacement at the top of abutment. As a result of the centrifugal tests, the horizontal displacement of abutment in the case 1 was 1.4cm that is almost coincide with the results of numerical and satisfy the allowable standard. On the other hand, the horizontal displacement of abutment in the case 2 was 12 cm that is 18% greater than that of numerical analysis and exceed the allowable standard. As a result of analysis, the maximum horizontal displacement of pile was 1.26 cm in case 1 that satisfies the criterion of allowable horizontal displacement (1.5 cm). In contrast, the maximum horizontal displacement of pile was 1.005 m in case 2 that greatly exceeds the allowable horizontal displacement.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.11
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• pp.7949-7956
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• 2015

This paper introduced the RAR(Reinforced Abutment for Railroads) to reduce settlement of transitional zone and horizontal displacement of abutment by constructing backfill before abutment. We expect that it has more economical and better performance which was validated by numerical analyses. First, transitional zone settlements and horizontal displacements of existing abutment were evaluated for various heights and ground conditions by using finite element analysis program. Then, numerical analyses of it under the same conditions were performed and its results were compared with existing abutment's ones. From the numerical analysis, we found that the responses(settlement and horizontal displacement) of transitional zone of the RAR is about 20% and 34% of one of existing abutment due to the effect of backfill stabilizing. We expected that the RAR having small foundations could be economic way to construct abutment with the control of responses such as, settlement, horizontal displacement, and earth pressure.

• Journal of the Korean GEO-environmental Society
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• v.8 no.5
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• pp.39-46
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• 2007

In this study, the centrifuge tests were performed to investigate the lateral flow behavior and stability of the ground improved by SCP. The centrifuge tests were fulfilled in the case of the back of abutment filled by EPS (case 1) and soil (case 2), and the potentiometer was installed on the abutment and embankment to measure the vertical and horizontal displacement at the top of abutment. As a result, the vertical displacement measured at the back of abutment was maximum 2.1 m, which was about 12% if compared with the height of embankment. In the case of the back of abutment filled by soil, the vertical and horizontal displacement measured at the top of abutment was 10 cm and 1.1 m, respectively, which exceeded the allowable horizontal displacement. On the other hand, in the case of the back of abutment filled by EPS, the vertical displacement of abutment did nor occur and the horizontal displacement was 1.4 cm. Therefore, the effect of SCP improvement with EPS method adopted to prevent the lateral flow and assure the stability of embankment on the soft ground was far superior.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.1-7
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• 2017

The RAR (Reinforced Abutment for Railways) is an economical abutment to reduce the settlement of a transitional zone and horizontal displacement of an abutment by constructing backfill before the abutment. In this paper, the performance of the RAR depending on the pile installation was evaluated using 2D (Dimensional) finite element analysis and compared with the existing abutment (with 5 rows pile). Numerical analysis showed that increasing pile installation is more effective in reducing horizontal displacement and earth pressure than settlement of the transitional zone. The horizontal displacement and earth pressure of the RAR was approximately 26~37% and 59~83% compared to the existing abutment by changing the pile installation. More pile installation led to a greater reduction of the horizontal displacement and earth pressure of the RAR. In addition, the horizontal earth pressure of RAR is influenced considerably by the reinforcement, pile, foundation, and stiffness of the ground.

• Journal of Korean Society of Steel Construction
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• v.19 no.6
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• pp.587-597
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• 2007

Steel restrainer cables for multiple frame bridges in California in the United States have been shown to be effective in preventing unseating at internal hinges during the past several earthquakes. Consequently, the steel-cable-restrainer is being tested for applications on multiple-span-simply-supported (MSSS) bridges in the mid-American region. In addition, shape memory alloy (SMA) bars in tension are being studied for the same application, multiple frame bridges, the developed seismic forces are transferred to piers through the restrainers. However, in MSSS bridges, the seismic forces are transferred to abutments by the restrainers. Therefore, the abutment' behavior should also be investigated. In this study, we assessed the seismic performance of the three types of restrainers, such as steel restrainer cables, SMA in tension, and SMA in bending for an MSSS bridge from moderate to strong ground motion, bending test of an SMA bar was conducted and its analytical model was determined for this study. Nonlinear time history analyses were conducted to assess the seismic responses of the as-built and the retrofitted bridges. All three types of restrainers reduced the hinge opening and the SMA in tension was the most effective of the three devices in preventing the unseating, all restrainers produced damage on the abutment from the pulling action of the MSSS bridge due to strong ground motions, was found that the retrofit of the abutment in the pulling action is required in the installation of restrainers in MSSS bridges.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.1
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• pp.195-205
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• 2013

This study, using the MCC Model to consider consolidation, estimated the range within which no influences occur from lateral movement and its amount of the foundation pile and abutment on the soft ground. This study performed finite element analyses, with variations on the adhesiveness and internal friction angle, depth of soft clay, embankment height, consolidation parameters, and separation distance between the abutment and embankment. The abutment's horizontal displacement exhibits linear change with a longer separation distance, and changes into an exponential form as the embankment gets closer to the abutment. As the soft clay layer becomes 10 m deeper, the horizontal displacement tends to increase 1.5~3.0 times. However, it decreases at a rate of 0.3~0.95 when adhesiveness is increased by 10 $kN/m^2$ and internal friction angle is increased by $5^{\circ}$. The increase change rate in a lateral movement amount becomes greater if it is closer to the abutment when the abutment separation distance is long. When the distance is short, the change rate of horizontal displacement increases in similar a way, but it tends to be decreasing overall.

• Journal of the Korean GEO-environmental Society
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• v.21 no.5
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• pp.13-21
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• 2020

In this study, the reliability of the lateral spring constant (k1) applied during design of pile foundation for bridge abutment was evaluated. To do this, the reliability of the factors related to the prediction of the lateral displacement of the abutment pile foundation, which was designed based on the displacement method proposed by Chang (1937), was analyzed. The data used for analysis were the design statements of ◯◯ bridge and ◯◯ IC2 bridge. Then, it was derived by comparing with the numerical analysis (p-y analysis) based on the basic data.

• Journal of the Korea Concrete Institute
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• v.23 no.5
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• pp.667-674
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• 2011

This paper discusses the analysis method of prestressed concrete girder integral abutment bridges for a 75-year bridge life and the development of prediction models for abutment displacements under thermal loading due to annual temperature fluctuation and time-dependent loading. The developed nonlinear numerical modeling methodologies considered soil-structure interaction between supporting piles and surrounding soils and between abutment and backfills. Material nonlinearity was also considered to simulate differential rotation in construction joints between abutment and backwall. Based on the numerical modeling methodologies, a parametric study of 243 analysis cases, considering five parameters: (1) thermal expansion coefficient, (2) bridge length, (3) backfill height, (4) backfill stiffness, and (5) pile soil stiffness, was performed to established prediction models for abutment displacements over a bridge life. The parametric study results revealed that thermal expansion coefficient, bridge length, and pile-soil stiffness significantly influenced the abutment displacement. Bridge length parameter significantly influenced the abutment top displacement at the centroid of the superstructure, which is similar to the free expansion analysis results. Developed prediction model can be used for a preliminary design of integral abutment bridges.