• International Journal of Highway Engineering
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• v.10 no.2
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• pp.193-203
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• 2008

This study was conducted to investigate the feasibility of the expedite construction of new pavement systems using precast concrete slabs and to develop the design and construction guide based on the results of the experimental construction. Half scale concrete slabs were designed and fabricated and the optimal reinforcement design, linkages between the slabs in the longitudinal and transverse directions, and the grouting methods were investigated. The experimental construction was performed fast and easily by assembling two slabs in the longitudinal direction and the other two in the transverse direction. The slabs were leveled and the pockets and the space between the slab bottom and the underlying layer were grouted. From the experimental construction, details about the design and construction of the precast pavements were acquired. Finally, the design and construction guide for the newly constructed precast concrete pavement systems was developed.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.53-54
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• 2009

Steel-embedded composite piers provide flexible design alternatives to satisfy the required performance due to various design parameters of composite sections. For the fast construction of composite piers, bolt connection can be utilized for small size piers and post-tensioning to the pier segments for the large size piers. In this paper, experimental results on composite piers were investigated to evlauate the effects of design parameters on the behavior of composite piers. Appropriate sections and their integration methods were suggested according to the design conditions. For the modular construction of bridge piers, pier segments need to be divided considering their weight and careful considerations on details to adjust fabrication and construction error. Connection details for the pier cap were also proposed.

• Magazine of the Korea Concrete Institute
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• v.9 no.1
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• pp.68-75
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• 1997

• Proceedings of the Korean Geotechical Society Conference
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• 1993.04a
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• pp.91-115
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• 1993

최근 환경문제에 대한 사회적 관심이 고조됨에 따라 말뚝항타로 인한 지반진동, 소음 등이 각종 건설현장에서 심각한 문제점으로 대두되고 있다. 지반을 굴착하고 cement paste를 주입한후 기성말뚝을 삽입하는 SIP공법은 이러한 건설환경 여건의 변화에 부응하여 그 적용이 급속히 증대되고 있다. 그러나 국내에서 SIP공법으로 시공딘 말뚝의 재하시험 결과는 각종 문헌에서 제시학 있는 지지력 산정공식들과는 상이한 특성을 나타내 주고있다. 또한 말뚝의 품질관리를 위한 시험결과는 상당한 지지력 미달현상이 발생학 있는 것으로 나타나고 있어 본 공법에 대한 지지력 특성이 규명되어야 할 필요가 있다. 본 논문에서는 국내에서 시공된 사례들을 중심으로 SIP공법의 지지력 특성을 분석하여 보았다.

• Journal of the Korean Society for Railway
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• v.18 no.6
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• pp.543-551
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• 2015

Quick-hardening track (QHT) is a construction method which is used to change from old ballast track to concrete track. Sufficient time for construction is important, as the construction should be done during operational breaks at night. Most of the time is spent on exchanging the ballast layer. If it is possible to apply the ballast non-exchange type of quick-hardening track, it would be more effective to reduce the construction time and costs. In this paper, pouring materials with high permeability are suggested and a construction method involving a layer separation pouring process considering the void condition is introduced in order to develop ballast non-exchange type of QHT. The separate pouring method can secure the required strength because optimized materials are poured into the upper layer and the lower layer for each void ratio condition. To ensure this process, a rheology analysis was conducted on the design of the pouring materials according to aggregate size, the aggregate distribution, the void ratio, the void size, the tortuosity and the permeability. A polymer series was used as the pouring material of the lower layer to secure the void filling capacity and for adhesion to the fine-grained layer. In addition, magnesium-phosphate ceramic (MPC) was used as the pouring material of the upper layer to secure the void-filling capacity and for adhesion of the coarse-grained layer. As a result of a mechanics test of the materials, satisfactory performance corresponding to existing quick-hardening track was noted.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.3
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• pp.363-375
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• 2019

Since the double-deck tunnel is deeply constructed in the city, it is necessary to secure the installation space of air supply and exhaust, escape passage stairs, elevator, distribution facilities and connection tunnels in the vertical shaft for the double-deck tunnel. Also, in order to minimize the effect of construction on adjacent area, it is necessary to construct the concrete structures at high speed in vertical shaft after tunnel excavation. Therefore, the slabs and the stairs in vertical shaft are needed to be constructed using precast concrete, and the rapid construction techniques of bracket for supporting the inner precast structure are needed. The bracket installation methods include cast-in-place concrete, precast concrete and steel. In this study, the improvement of the steel brackets with good economical efficiency and good workability was carried out in consideration of the improvement of the construction speed. We have developed a new bracket that is optimized through bracket shape improvement, anchor bolt position adjustment and quantity optimization. As a result of the structural performance test, it was confirmed that the required load supporting capacity was secured. As a result of structural performance test for bar type anchor bolt and bent anchor anchor bolt, it was confirmed that the required load carrying capacity was secured and that the load bearing capacity of bent anchor bolt was large.

• Journal of the Korean Geotechnical Society
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• v.16 no.6
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• pp.141-151
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• 2000

본 연구에서는 토사나 사석을 이용하여 자체를 축조하는 과정에서 발생하는 연약지반의 강제치환거동을 연구하기 위하여 다양한 시험조건에 대한 원심모셩을 수행하였다. 제체축조에 따른 연약지반의 강제치환거동은 제체의 성토시공방법, 성토재의 입경, 연약지반의 종류와 강도 등에 따라 맣은 차이를 보였는데, 특히 성토과정 중에 발생하는 과잉간극수압의 크기와 밀접한 상관관계를 보였다. 급속시공인 경우에 연약지반의 파괴영역은 회적으로 확대되고 성토사면의 기울기는 완만해졌으며, 성토재의 입경이 클수록 치환깊이가 증가하고 성토사면의 기울기가 급하게 형성되었다. 그리고 동일점토에서는 지반의 강도가 클수록 치환량이 적었지만, 점토의 종류가 다른 경우에는 지반내 발생하는 과잉간극수압의 크기와 소산성조에따라 치환거동이 많은 영향을 받는 것으로 나타났다.

• Magazine of the Korea Concrete Institute
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• v.23 no.1
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• pp.66-68
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• 2011

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 2000.09a
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• pp.84-87
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• 2000

최근 들어 구조물이 대형화되고 급속히 시공되는 경향이 증가함에 따라 구조물에 대한 변위측정은 시공중인 구조물뿐만 아니라, 그 사후관리 및 안전성 여부를 파악하는데 중요한 기초자료로 활용되고 있다. 특히, 해상에서 실시되는 방조제나 안벽 공사 등에서는 육상구조물에 비해 변위측정에 여러 가지 제약이 따른다. 이와 같은 해상 토목구조물의 거동을 다각적으로 파악하기 위한 연직 방향 및 평면 변위 측정에 GPS를 적용하면 신속하고 정확한 변위측정 자료를 획득할수 있다. (중략)

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.1
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• pp.23-34
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• 2013

In this study, a safe, economic, and rapid construction method of underground roadway using PSC girder is developed to reduce traffic congestion and maximize space usage in urban area. For an efficient application of the method, a rigid joint connection is proposed and tested. For the testing, cantilever specimens were used to verify its capacity. The parameters for this study were cross beam length and joint connection type. The results of the test showed that the proposed connection system has superior performances. Despite having differences of cross beam length and joint connection type, the stable flexural behavior was shown in all of the tested specimens. Also, the behaviors of PSC girders and upper slabs connected by the proposed method showed superior performance. Moreover, the improvement of structure performance according to the increase of length of cross beams has been verified.