• Journal of the Korean Geosynthetics Society
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• v.17 no.4
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• pp.179-188
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• 2018

A new style of panel-type reinforced earth wall is a more integrated structure by connecting the geosynthetic strip reinforcement with a folding groove directly to the front panel through C-shaped insertion hole embedded in the panel. In this study, field measurements were conducted on two reinforced earth walls constructed at different sites to assess the field applicability and structural stability of the new style of panel-type reinforced earth wall. The horizontal displacement of the front panel, tensile deformation of the geosynthetic strip reinforcement, and horizontal earth pressure acting on the panel were measured and analyzed through the field measurements. According to the field measurements, after completion of the reinforced earth wall construction, the maximum horizontal earth pressure applied to the front panel was less than two-thirds of the Rankine earth pressure, and the maximum horizontal displacement of the front panel was less than 0.5% of the wall height, and the maximum tensile strain generated on the reinforcement was less than 1.0%. Therefore, it was found that two reinforced earth walls constructed at different sites remained stable.

• Journal of Korean Tunnelling and Underground Space Association
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• v.12 no.2
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• pp.193-200
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• 2010

Due to the characteristic of culvert structure, the standard section of the culvert has been established and applied in field. However, this becomes a limitation in selecting a section design corresponding to various field conditions although it can improve the design and applicability of culvert structure. In order to overcome this limitation, we have developed the design and application technology of culvert structure corresponding to the field conditions that various shapes of culvert structure can be covered by assembly of precast segments. Because the structural characteristics of assembling-type waterway culvert structure, the thickness of structure and amount of reinforcing rods can vary according to the fixation or internal hinge status in the connection part of precast segments. This has a strong influence on the applicability and economic efficiency of culvert structure. Accordingly, in order to suggest a reasonable modeling technique of segment connection parts, this study has conducted the field experiment and numerical analysis. According to the results of field experiment and numerical analysis, the slab, wall and base slab with mortar splice sleeves have shown that the assembling-type of waterway culvert structure behaves like an integrated structure.

• The Magazine for Energy Service Companies
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• s.29
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• pp.48-61
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• 2004

최근 일본에서는 ESCO사업에 PFI법을 새로이 적용하고 있다. 성과배분제, 성과보증제에 이어 이 제도를 적용할 경우, 국가 및 공공기관을 대상으로 하는 ESCO사업의 확대 및 자금조달이 한층 유리해질 전망이다. 지난 99년 제정된 PFI(Private Finance Initiative)법(민간자금 등의 활용에 의한 공공시설 등의 정비 등의 촉진에 관한 법률)에 근거한 사업은 ''공공시설 등''에 있어서 건설, 유지관리 운영 등을 민간의 자금, 경영능력 및 기술적 능력을 활용하는 사업방법으로 사업 전체의 리스크관리가 효율적으로 행해지는 것과 설게$\cdot$시공$\cdot$유지관리$\cdot$운영의 전부 또는 일부를 일체적으로 취급하는 것에 의해 사업비용의 절감이 기대되며 질 높은 서비스의 제공이 가능한 제도이다. 이것과 매우 유사한 개념을 가지고 있는 것이 성과보증제에 의한 ESCO사업이다. 민간사업자인 ESCO사업자가 자금을 조달하고 에너지절약 개수공사에 따른 설계$\cdot$시공$\cdot$, 운전$\cdot$유지관리, 계측$\cdot$검증, 에너지절감 보증 등의 서비스를 제공하며, 광열수도비 및 운전$\cdot$유지관리비의 절감분으로 모든 투자와 ESCO사업자의 경비를 지불한다. 또 에너지절감 및 공공의 이익보증을 포함한 퍼포먼스계약이라고 하는 형태를 취하는 것으로 공공 이익의 최대화를 도모함과 동시에 금융기관의 투자 리스크에 관한 우려를 회피할 수도 있다. 또 PFI법 특유의 법제상, 재정상의 조치와 재정상 및 금융상의 지원이라는 배려에 있다. 예를 들면, 국고채무부담행위의 설정, 행정재산 사용료의 무상화 또는 감면, 프로젝트 파이낸싱 등에 의한 자금조달을 고려할 경우에 있어서 담보권의 설정 등에 관한 제도를 합리적으로 정비하는 것이 가능하게 된다. 그 내용의 대강을 살펴본다.

• Journal of the Korean Geosynthetics Society
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• v.14 no.3
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• pp.31-42
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• 2015

The Reinforced subgrade for railroad (RSR) was constructed for one way railway line with the dimension of 5 m high, 6 m wide and 20 m long to evaluate its performance under train design load. The RSR has characteristics of short length (0.3-0.4 H) of reinforcement and rigid wall, 30 and 40 cm vertical spacing of reinforcement installation. To enhance economics and constructability, three kinds of connections (welding, hinge & bolt, bold wire) were also designed to realize the integration between rigid wall and reinforced subgrade. Two times of static loading tests were done on the full size railroad subgrade. The maximum applied pressure was 0.98 MPa (the maximum test load 5.88 MN), which corresponds to 19.6 times of the design load for railroad subgrade, 50 kPa. The performance on the RSR was evaluated with the safety on the failure, subgrade bearing capacity and settlement, horizontal displacement of wall, and reinforcement strain. Based on the full scale test, we confirmed that the RSR with the conditions of 0.35 H (35% of height) short reinforcement length, hinge & bolt type connection for integration between rigid wall and reinforced subgrade, and 40cm vertical spacing of reinforcement installment shows good performance under train design load.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.604-609
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• 2016

This study evaluated the long-term performance of RSR (Reinforced Subgrade for Railways) technology which increases the railway line capacity without the need for additional land. Its characteristics include the use of a short reinforcement with rigid wall, which make it possible to apply it in confined spaces. The 7m high and 40m long testbed employed to evaluate the long-term performance was designed and constructed near Jupo station on the Chang-hang line. This line, located close to a local bus route, had collapsed at the subgrade following heavy rainfall. The performance of the new type of subgrade was verified with long term measurements over a 2 year period including the surface and ground settlement, horizontal displacement of the wall, tensile strain of the reinforcement, and settlement of the rail top on the side track. Based on the results of the measurements made until now, we concluded that it had sufficient safety and serviceability for use as a railway subgrade. It is expected that RSR technology could be frequently used at sites which lack the necessary construction materials for an embankment and are located close to functional railway lines and boundaries, in order to settle civil complaints.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.143-144
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• 2009

This study is a development of new PSC girder overcomes weakness of the existing PSC girder and has advantage of construction mark, economical efficiency and maintenance. The gole of this study is reducing dead-load and long-span as HWPC girder has same section through hole and multi-prestressing.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.1
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• pp.39-47
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• 2016

Repair methods of aging concrete pavement are generally used composite structure pavements, such a composite structure is subjected to a large impact on the mechanical behavior and ensure long-term commonality integrated under vehicle loads, environmental loads of the public in accordance with the bond strength between old and new concrete. A common of bonded concrete overlays that are currently available is Interface arrangements using a variety of equipment to ensure the excellent bond strength between old and new concrete than standard concrete, mixed with a material such as a polymer in order to improve the adhesion with the material itself. However, these method of constructions are being applied, depending on the developer site presents no special specifications apply when a specific application criteria objectively, this is due to the situation of each individual method, which is based on the difficulty in quality control of the site manager. In this study by performing a field test for polymer content via the variables that contribute most significantly to ensure bond strength and the field element core of the interface processing method and materials to ensure bond strength between the old and the new concrete, it was to derive the construction site construction method that can improve the performance of the bond strength through a review of the construction around the correlations and the bond strength according to the effective performance analysis of the conventional surface treatment process and variation of polymer volume fraction.

• Journal of Korean Tunnelling and Underground Space Association
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• v.22 no.5
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• pp.485-500
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• 2020

Due to various advantages such as small facilities, ease of construction and so on, the grouting technology which is widely used in construction field has developed remarkably compared with the past. However, the efforts to improve the homogeneity of quality, long-term durability and environmental problems have been continued. In recent years, new grouting method has been developed in order to solve problems such as low strength, durability and leaching phenomenon of liquid glass (sodium silicate) grouting material in Korea. A newly developed method integrates the injection material with the ground by the self-healing material of crystallization growth type. For this reason, it is known that improvement of the durability and water quality of the ground, prevention of leaching, and environment friendliness can be expected. The present study applied a newly developed method to test sites and verified its effect such as injection range, improvement effect, waterproofing performance and so on. Standard penetration test, field permeability test, borehole shear test, pressuremeter test and pH test were conducted, and the results were compared between before and after developed method application. As results of tests, the field applicability and improvement effect of developed method were proved to be excellent.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.34 no.6
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• pp.417-426
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• 2021

Recently, use of the precast concrete (PC) system, which can increase economy by minimizing field work, has rapidly increased. However, the PC system cannot exhibit structural performance under construction, specifically before integration between members. Furthermore, since it is difficult to secure the structural integrity of beam-column joints even after construction, the PC system is vulnerable to progressive collapse. In the PC system, various types of details for PC beam-column joints have been proposed, while the structural/construction details of PC system generally used in Korea differ from those of overseas PC systems. However, studies on the progressive collapse of the domestic PC system are limited. Thus, in this study, we investigated the structural/construction details of PC beam-column joints mainly used in Korea. Based on the investigation, for the prototype PC system with typical joint details, a nonlinear finite element analysis was carried out to evaluate its structural performance under progressive collapse. Further, a parametric study was performed, and the effect of the design parameters was investigated, to recommend a method to improve the progressive collapse resistance of the PC system.

• Journal of Korean Society of Steel Construction
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• v.16 no.2 s.69
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• pp.235-245
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• 2004

The advantages of composite construction are now well understood in terms of structural economy, good performance in service, and ease of construction. However, these conventional composite construction systems have some problems in application to steel framed buildings due to their large depth. So, in this study we executed an experimental test with the "Slim Floor"system which could reduce the overall depth of composite beam. Slim Floor system is a method of steel frame multi-story building construction in which the structural depth of each floor is minimized by incorporating the steel floor beams within the depth of the concrete floor slab. Presented herein is an experimental study that focuses on the flexural behaviour of the partially connected slim floor system with asymmetric steel beams encased in composite concrete slabs. Eight full-scale specimens were constructed and tested in this study with different steel beam height, slab width, with or without shear connection and concrete topping thickness. Observations from experiments indicated that the degree of shear connection without additional shear connection was $0.53{\sim}0.95$ times that of the full shear connection due to inherent mechnical and chemical bond stress.