• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.224-231
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• 2005

The ground excavation causes the deformation of the ground where the neighborhood structure is located. The ground deformation result in the vertical settlement of the neighborhood structure as well as the horizontal displacement of the temporary earth retaining structures. The decreased volume of the soil due to the ground settlement is defined as 'the ground loss quantity' or 'the ground loss'. When excavation is performed nearby existing structures, retaining walls should be designed and constructed to minimize the ground loss. Among various methods for reducing the ground loss, this study introduces the pre-loading method which has been recently developed. The reduction effect of the ground loss by pre-loading has been found to be larger as using a wall with relatively smaller rigidity.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.806-809
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• 1996

The present development relates to an apparatus for loading or unloading a workpiece, and more particularly, to an apparatus for loading or unloading a workpiece from a press die or supplier An apparatus for loading or unloading a workpiece has been installed in a press in order to load or unload a workpiece from a press die. There has been known such a loading or unloading apparatus as the apparatus can feed a workpiece in not only the horizontal direction but also in the vortical direction. Press working system in automotive factories are now switching over to a transfer press work ing system. The current problem to be sieved immediately is to automate the existing manual press lines for the manpower saving and speedy production. “Automation system for press line”has just been developed to meet the above trend. The loader and unloader are development under the design concept for high performance, easy control and operational safety to meet the more extensive.

• Earthquakes and Structures
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• 제10권3호
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• pp.613-628
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• 2016

The effectiveness of the use of modern repair schemes for the seismic retrofit of existing RC structures were assessed on a comparative experimental study of carbon fiber-reinforced polymer (CFRP) strips and sheets for the repair of reinforced concrete members of RC frames, damaged because of cyclic loading. Two virgin, single - story, one - bay, 1/3 - scale frame specimens were tested under cyclic horizontal loading, up to a drift level of 4%. Then, virgin specimens, B and F, respectively, were repaired and retested in the same way. One, specimen RB, was repaired with epoxy injections and CFRP strips and one, specimen RF, was repaired with epoxy injections and CFRP sheets. The two specimens are used to examine the differences between the structural behavior of frames repaired using CFRP strips and frames repaired using CFRP sheets. Both qualitative and quantitative conclusions, based on the observed maximum loads, loading and reloading stiffness, hysteretic energy absorption and failure mechanisms are presented and compared. The repaired frames recovered their strength, stiffness and energy dissipated reasonably. The use of CFRP sheets was found more effective than CFRP strips, due to the proper anchorage.

• 한국지반공학회논문집
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• 제30권3호
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• pp.29-46
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• 2014

모래지반의 지표면에 위치한 거친 바닥면을 가진 강체 원형기초에 대하여 삼차원 수치해석을 통하여 수직-수평 조합하중 조건에서의 지지력을 구하였다. 조합하중 상관도를 효율적으로 산출할 수 있는 swipe 재하방법과 실제 구조물의 하중 조건과 유사한 probe 재하방법을 모사할 수 있는 수치모델을 구현하였으며 요소망의 조밀도에 의한 오차를 소거할 수 있는 분석 절차를 개발하였다. Mohr-Coulomb 소성모델을 사용하고 관련흐름법칙을 적용하여 지반의 내부 마찰각에 따른 수직-수평 조합하중에 대한 지지력 상관도와 경사계수를 산출하였다. Swipe 재하방법의 결과는 probe 재하방법을 사용한 결과와 유사함을 확인하였으며, 거친 바닥면 조건에서 수직-수평 조합하중 지지력 상관도의 내부 마찰각에 따른 변화는 미미하고, 원형기초에 대해서 연속기초 및 사각형기초와 동일한 경사계수를 적용할 수 있는 것으로 나타났다. 하중의 경사가 큰 경우에는 수치모델링을 통해 산출된 원형기초에 대한 지지력 상관도와 경사계수는 기존의 연구 결과보다 작게 평가되었으며, 수치모델링 결과에 영향을 미치는 요인과 향후 연구 방향에 대하여 고찰하였다.

• 한국터널지하공간학회 논문집
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• 제9권4호
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• pp.331-341
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• 2007

기존터널에 근접 굴착 할 때 발생하는 흙막이벽체의 수평변위를 억제시키기 위해 버팀대에 선행하중을 가했다. 이러한 목적으로 흙막이벽체에 큰 선행하중을 가할 수 있는 새로운 선행하중 시스템을 모형시험에 적용하였다. 대형 시험은 폭 2.0m, 높이 6.0m, 길이 4.0m인 모형 토조에서 수행하였고 시험지반은 모래로 조성하였다. 직경 1.2m인 모형 터널은 시험지반 굴착 전에 설치하고 지반을 조성한 후에 모형터널에 근접해서 흙막이벽체를 설치하고 시험지반을 굴착하면서 모형 터널과 흙막이벽체 및 지반의 거동을 측정하였다. 이때에 선행하중 재하효과를 확인하기 위하여 선행하중을 가하지 않는 시험은 물론 선행하중을 가하여 흙막이벽체의 수평변위를 억제하는 시험을 실시하였고 수치해석을 실시하여 대형 시험결과와 비교하였다. 그 결과 선행하중을 설계축력 이상으로 적용시켜 흙막이벽체의 수평변위를 감소시켰을 때 벽체 배면에 있는 기존 터널의 안정성이 크게 향상되는 것을 확인할 수 있었다.

• Geomechanics and Engineering
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• 제31권6호
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• pp.599-614
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• 2022

One of the methods of stabilizing retaining walls, embankments, and deep excavations is the implementation of plate anchors (like the Geolock wall anchor systems). Back-to-back Mechanically Stabilized Earth (BBMSE) walls are common stabilized earth structures that can be used for bridge ramps. But so far, the analysis of the interactive behavior of two back-to-back anchored walls (BBAW) by double-plates anchors (constructed closely from each other and subjected to the limited-breadth vertical loading) including interference of their failure and sliding surfaces has not been the subject of comprehensive studies. Indeed, in this compound system, the interaction of sliding wedges of these two back-to-back walls considering the shear failure wedge of the foundation, significantly impresses on the foundation bearing capacity, adjacent walls displacements and deformations, and their stability. In this study, the effect of horizontal distance between two walls (W), breadth of loading plate (B), and position of vertical loading was investigated experimentally. In addition, the comparison of using single and equivalent double-plate anchors was evaluated. The loading plate bearing capacity and displacements, and deformations of BBAW were measured and the results are presented. To evaluate the shape, form, and how the critical failure surfaces of the soil behind the walls and beneath the foundation intersect with one another, the Particle Image Velocimetry (PIV) technique was applied. The experimental tests results showed that in this composite system (two adjacent-loaded BBAW) the effective distance of walls is about W = 2.5*H (H: height of walls) and the foundation effective breadth is about B = H, concerning foundation bearing capacity, walls horizontal displacements and their deformations. For more amounts of W and B, the foundation and walls can be designed and analyzed individually. Besides, in this compound system, the foundation bearing capacity is an exponential function of the System Geometry Variable (SGV) whereas walls displacements are a quadratic function of it. Finally, as an important achievement, doubling the plates of anchors can facilitate using concrete walls, which have limitations in tolerating curvature.

• 한국가구학회지
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• 제23권3호
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• pp.290-297
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• 2012

Recently, interest in wooden construction have been growing by increasing needs and demands for eco-friendly and traditional wooden building(Hanok). Especially, Hanok has the technical development in manufacturing the mortise-tenon joint without fasteners(precut), so it could be called to modernization, industrialization and popularization. But the structural design and analysis of the structure were not regulated and had the difficulty to consider the variation of wooden member and to conduct the difficulty in the structural analysis and the design of the joint. In this study, the stiffness ratio of wooden mortise and tenon joint was evaluated according to the vertical loading, lintel and loading speed. The joint was distinguished in semi-rigid joint regardless of their factors. The stiffness ratio was 0.40 in vertical loading, 0.50 without vertical loading and 0.44 in horizontal loading with high speed. This study would be utilized to the structural analysis and design with structural analysis and design program.

• Computational Structural Engineering : An International Journal
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• 제3권1호
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• pp.9-17
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• 2003

This paper aims at investigating the damage process of steel members leading to the failure under strong repeated loading, proposing the damage index using various factors related to the damage, and developing the analysis method for evaluating the damage state. Cantilever-type steel members were analyzed under uniaxial load and combined with a constant axial load, considering a horizontal displacement history. In analyzing the models, loading patterns and steel types (SS400, SM570, Posten80) were considered as main parameters. From the analysis results, the effects of parameter on the failures mode, the deformation capacity, the damage process are also discussed. Each failure process was compared as steel types. Consequently, the failure of steel members under strong repeated loading was determined by loading. Especially it was seen that the state of the failure is closely related to the local strain.

• 한국해양공학회지
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• 제27권1호
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• pp.59-66
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• 2013

A suction anchor is one of the most popular anchors for deepsea floating systems. An anchor used for catenary mooring is predominantly under a horizontal load. In this study, the behavior of a suction anchor installed in cohesionless soil was investigated when the anchor was mainly subjected to a horizontal load induced by a catenary line. In order to study the behavior of the suction anchor, 3D FEM analysis models were developed and analyzed. Depending on the location of the load (padeye), the ultimate horizontal load was monitored. The distributions of the reaction forces around the anchor induced by the seabed were analyzed using the circumferential stress to understand the behavior of the suction anchor under a horizontal load.

• International Journal of Concrete Structures and Materials
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• 제9권1호
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• pp.61-67
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• 2015

The concept of horizontal shear connection utilization on wood-concrete beams intends to be an alternative connection detail for composite wood-concrete decks. The volume of sawn-wood is over three times more expensive than concrete, in Brazil. In order to be competitive in the Brazilian market we need a composite deck with the least amount of wood and a simple and inexpensive connection detail. This research project uses medium to high density tropical hardwoods managed from the Brazilian Amazon region and construction steel rods. The beams studied are composed of a bottom layer of staggered wood boards and a top layer of concrete. The wood members are laterally nailed together to form a wide beam, and horizontal rebar connectors are installed before the concrete layer is applied on top. Two sets of wood-concrete layered beams with horizontal rebar connectors (6 and 8) were tested in third-point loading flexural bending. The initial results reveal medium composite efficiency for the beams tested. An improvement on the previously conceived connection detail (set with six connectors) for the composite wood-concrete structural floor system was achieved by the set with eight connectors. The new layout of the horizontal rebar connectors added higher composite efficiency for the beams tested. Further analysis with advanced rigorous numerical Finite Element Modeling is suggested to optimize the connection parameters. Composite wood-concrete decks can attend a large demand for pedestrian bridges, as well as residential and commercial slabs in the Brazilian Amazon.