• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.3
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• pp.211-218
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• 2006

From the development of residential flat plate system, continuously bended shear reinforcement is developed for the prevention of punching shear. To know the punching shear capacity of developed shear reinforcement in slab-column joint, structural test is performed. The testing parameters are shear reinforcement types, such as no reinforcement, bended shear reinforcement, and head stud reinforcement. To verify the lateral capacity, cyclic load is applied under the constant vertical load condition. The results of tests are compared to as global displacement, slab-column joint strength. From the test results, the resisting capacity of developed shear reinforcement system has a good performance in the story drift ratio.

• 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 the Computational Structural Engineering Institute of Korea
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• v.22 no.5
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• pp.501-507
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• 2009

By using topology and shape optimization, a theoretically optimum FRP deck was proposed. Firstly, a topologically optimal shape, truss-like structure without hinges, was found. A truss-shape frame is the most ideal structure when subjected to a concentrated force at the center of simply supported beam. An armature was found at the point joining horizontal chord and diagonal chord, which was used as a new design variable. Secondly, optimum value of each variable was decided through shape optimization using genetic algorithm. To compare it with existing commercial FRP decks, shape optimization was performed by fixing the height of FRP decks. To verify the performance of the FRP deck proposed in this study, a finite element analysis was performed. As a result, it satisfies serviceability and safety guide lines of FRP decks.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1994.04a
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• pp.116-121
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• 1994

지금까지 대형 구조물에 널리 사용되고 있는 Base Isolator는 특히, 지진하중에 대하여 상부 구조물의 지반분리(base isolation)을 이용한 지진제어를 목적으로 하기 때문에 Seismic Isolator라 한다. 일반적으로 면진베어링에는 LRB(Laminated Rubber Bearing) 방식과 R-FBI(resilient-friction base isolator) 방식으로 크게 나눌 수 있다. LRB 방식은 가장 널리 사용되는 면진베어링으로써 방진고무를 주된 재료로 하고 수직강성을 보강하기 위하여 steel plate를 조합하여 제작하며, 초기강성 및 에너지 소산능력을 증가시키기 위하여 단면중앙에 납(lead plug)를 삽입하기도 한다. R-FBI 방식은 방진고무 적층판 내부에 미끄럼판을 가지고 있으므로 LRB 방식에 비하여 더 큰 수평변위를 발생시킬 수 있다. 이번에 설계 제작한 면진베어링은 LNG 저장탱크의 Seismic Isolation을 목적으로 적용대상의 사양에 맞추어 설계 제작하고 성능평가 시험을 수행하여 LNG 저장탱크, 원자로, 대형 건축물등 지진으로부터 보호되어야 하는 대형구조물의 방진재로 적용할 수 있는가를 평가하고자 한다. 본 논문에서는 제작된 면진베어링의 설계를 검증하고 방진고무(HDR)재료의 물리적 특성시험, 축소모델에 의한 정적, 동적시험을 통하여 시험방법을 소개하고 이러한 시험결과를 기초로 하여 면진베어리의 성능을 평가하였으며, 면진베어링의 온도변화, 외부 수직하중의 변화등에 따른 특성변화와 LNG 저장탱크와 면진베어링의 체결방법에 따른 시험으로 체결방법을 검증하였으며, 대상물의 사양에 적합한가를 고찰하였다.

• The Journal of the Convergence on Culture Technology
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• v.5 no.3
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• pp.345-349
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• 2019

In Korea, the mountainous area occupies more than 70% of the whole country, cutting of earth slope that cuts a part of the ground surface is widely used when building infrastructures such as road, railroad, and industrial complex construction. In recent years, regulations on environmental damage have become more strict, and various methods have been developed and applied. Among them, Concrete-Panel Retaining Wall technique is actively applied. Concrete-Panel Retaining Wall is a method to resist horizontal earth pressure by forming a wall by attaching a precast retaining wall to the front of the support material and increasing the shear strength of the disk through reinforcement of the support material. Soil nailing, earth bolt, and ground anchor are used as support material. Among them, ground anchor is a more aggressive reinforcement type that introduces tensile load in advance to the steel wire, and a large concentrated load acts on the front panel. This concentrated load is a factor that creates cracks in the concrete panel and reduces the durability of the retaining wall itself. In this study, steel pipe sleeves and reinforcements were purchased at the anchorage of the panel to prevent cracks, and by applying bumpy shear keys to the end of the panel, the weakness of the individual behavior of the existing grout anchors was improved. The problem of degraded landscape by exposure to front concrete of retaining wall and protrusion of anchorage was solved by the production of natural stone patterns and the construction of sections that do not protrude the anchorage. In order to verify the effectiveness of anti-crack sleeves and reinforcements used in the null, indoor testing and three-dimensional numerical analysis have been performed, and the use of steel pipe sleeves and reinforcements has demonstrated the overall strength increase and crack suppression effect of panels.

• Journal of the Korean Geosynthetics Society
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• v.3 no.1
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• pp.3-15
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• 2004

Geogrid reinforced soil structures with segmental block facing have been increased since 1990's, because of the convenience of installation and the flexible appearance. In this paper, the behavior of the segmental reinforced retaining wall was analysed with the results of field monitoring. The height and length of reinforced wall are 12m and 25m, respectively. The field measurement equipments are horizontal and vertical earth pressure cells, settlement plate, strain gauge, inclinometer, and displacement pin. Based on the field monitoring, the horizontal earth pressure was approximately 0.3times higher than that of the theoretical method and the maximum tensile strength of reinforcement was 26.2kN/m. The displacement of facing wall was 23mm at the point of 7.1m height of the wall and toward the wall facing. The results of the study indicate that the segmental reinforced retaining wall is in a stable condition because of good compaction & reinforcement effects, and long period of construction time. Finally, the computer program of SRWall is very useful tool to design the segmental reinforced retaining wall.

• Journal of Chest Surgery
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• v.42 no.6
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• pp.777-780
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• 2009

We reported here on 2 cases of aortic regurgitation (AR) that were due to avulsion of the aortic valve commissure. Aortic valvuloplasty was attempted in both cases. In the 1st case, valvuloplasty was performed with reattaching the commissure using the 5-0 polypropylene continuous suture technique. However, aortic regurgitation recurred and this lead to reoperation on the postoperative $14^{th}$ day. The intraoperative finding revealed a completely re-detached commissure that required mechanical valve replacement. In the second case, we attempted to reattach the commissure using pledgetted multiple transverse mattress sutures with 5-0 polypropylene. Because the leaflet coaptation was incomplete, the aortic valve was replaced with a tissue valve.

• Journal of the Korean Wood Science and Technology
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• v.42 no.6
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• pp.708-713
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• 2014

Trusses are widely used for wooden houses in the areas where wood construction in generalized for residential housings such as North America, Australian, New Zealand. In Korea, joist and rafter system is generally used because of the production cost, transportation cost and lack of experience required for truss manufacturing. In this study, roof trusses and flat trusses were manufactured by using oriented strand board (OSB) gusset plates for field assembly and tested under bending load to obtain the allowable loads. The allowable load and the actual load of 6m span roof trusses were 10.60 kN and 5.26 kN, respectively, which is regarded to be sufficient for use in construction. The allowable load and the actual load of 6m span floor flat trusses were 7.18 kN and 7.43 kN, respectively. For flat trusses, the allowable load is slightly lower than the actual load but the difference in very small, and it is thought that flat trusses can be used for construction by applying small change of structures and members.

• Journal of the Korean Geotechnical Society
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• v.30 no.12
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• pp.63-72
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• 2014

To observe the behavior of lateral deformation of buried pipe and the preventing effect of embankment piles against the lateral deformation, a series of full-scale field tests were performed on a reclaimed coastal area. A buried pipe was installed in the west coast undergoing reclamation and embankment was performed by three steps. Then vertical settlement and lateral displacement were measured by the settlement plate and the inclinometer. Embankment pile system were applied to prevent the lateral displacement of buried pipe. Heave of the buried pipe slightly happens during embankment and following settlement. Finally the behavior steadily converged. The preventing effect of the embankment pile was approximately two times stronger than non-reinforcement. Both settlement and lateral displacement appear to be bigger at upper ground and smaller at lower ground.

• The Journal of Engineering Geology
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• v.26 no.1
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• pp.51-61
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• 2016

New building methods are needed to aid increased inner-city redevelopment and industrial construction. A particular area of improvement is the efficient use of cut slopes, with the minimization of associated problems. A retaining wall of precast panels can resist the horizontal earth pressure by increasing the shear strength of the ground and reinforcing it through contact with the panels. Precast panels allow quick construction and avoid the problem of concrete deterioration. Other problems to be solved include the digging of borrow pits, the disposal of material cut from the slope, and degradation of the landscape caused by the exposed concrete retaining wall.This study suggest the methods of improvement of an existing precast panel wall system by changing the appearance of the panels to that of natural rock and improving the process of adhering the panel to a vertical slope. The panels were tested in the laboratory and in the field. The laboratory test verified their specific strength and behavior, and the field test assessed the panels' ground adherence at a vertical cutting. Reinforcement of the cutting slope was also measured and compared with the results of 3D numerical analysis. The results of laboratory test, identified that the shear bar increase the punching resistance of panel. And as a results of test construction, identified the construct ability and field applicability of the panel wall system adhered to in-situ ground. In addition to that, extended measurement and numerical analysis, identified the long-term stability of panel wall system adhered to in-situ ground.