• 레미콘
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• no.1 s.38
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• pp.12-40
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• 1994

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.5
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• pp.1166-1172
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• 2007

Drainage pipeline system repaired by trenchless technology using liners can be defined between partial and entire collapse. The liners in the partial collapse pipeline are subjected to only uniform groundwater pressure on the surface. This research evaluates practical and useful cured-in-placed pipe (CIPP) design equations based on experimental results and finite element analysis results. Also, stability evaluation of pipe liner system with edge treatment is performed using finite element analysis. The CIPP equation should be used to design liner pipe system.

• Journal of Korean Association for Spatial Structures
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• v.6 no.2 s.20
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• pp.123-129
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• 2006

Recently, many researches have been conducted about reinforced concrete structures strengthened with FRP plates. In case of structures strengthened with FRP plates, the issue of premature debonding FRP plate has been raised through many previous researches. The purpose of this paper is what structural behavior and flexaural capacity of reinforced concrete beams which are strengthened for flexure is investigated about the using secondary ironware in the method of external bonded CFRP plate, and the method of near surface mounted CFRP-Rod. Also, in order to evaluate flexural capacity, experiments of the reinforced concrete beams with exteranl bonded CFRP plate and near surface mounted CFRP-Rod have been compared and investigated.

• Magazine of the Korea Concrete Institute
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• v.17 no.4 s.87
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• pp.57-67
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• 2005

• Journal of the Korea Construction Safety Engineering Association
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• s.31
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• pp.60-72
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• 2005

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.2
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• pp.267-275
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• 2023

As aged infrastructures have been increased, the importance of accurate maintenance costs and proper budget allocation for infrastructure become prominent under limited resources. This study proposed a mapping algorithm between representative defects, repair methods, and the estimated maintenance costs for concrete bridges. In this regard, using BMS (Bridge Management System) data analysis, bridge repair methods were classified and matched with defects according to their locations, types, and sizes. In addition, the maintenance costs were estimated based on the amount of work-load and quantity per unit using CSPR (Cost Standard Production Rate). As a result, the level of accuracy was an average of 85.1 % compared with the actual bill of quantity for Seoul bridge maintenance. The accuracy of maintenance costs is expected to be enhanced by considering the various site conditions such as pier height, extra charge conditions, additional equipment, etc.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.234-234
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• 2021

국내 기반시설의 대부분은 1970년대 경제성장기에 건설되어 사용연수가 30년 이상 경과하였고 급격한 고령화가 진행 중이다. 1990년대 성수대교와 삼풍백화점의 붕괴는 시설물 유지관리의 중요성에 대한 전국민적 관심을 집중시켰고, 이에 정부는 1995년 「시설물의 안전관리에 관한 특별법」 제정을 시작으로 현재까지 다양한 정책 및 기준을 수립해왔다. 일반적으로 안전점검 및 정밀안전진단 등을 수행하여 시설물의 안전등급을 평가하고 결함에 대한 보수·보강을 실시하여 시설물을 유지·관리하고 있다. 그러나 유지관리 예산은 한정적이기 때문에 모든 결함에 대한 보수·보강 사업을 실시할 수 없는 실정이다. 이에 보수·보강 조치의 우선순위를 선정하는 것이 필요하며, 관련 법령 세부지침에는 부재의 중요도, 결함의 심각성, 경제성을 고려한 우선순위지수(PI, Priority Index)를 제시하고 있다. 이 식은 전문가의 주관적인 판단에 의해 영향도를 50~100%범위 안에서 조정할 수 있으며, 일부 특정 부재는 동일한 가중치가 설정되어 있다. 또한 결정적으로 보수보강을 통한 효과를 효율적으로 고려하지 못하고, 대부분 경제성에 의해 우선순위가 결정되는 한계점이 발생한다. 따라서, 본 연구에서는 몇 가지 사례분석을 통해 현재 우선순위지수에 대한 문제점을 고찰하고 이를 개선할 수 있는 우선순위 산정식(PI)을 제시하였다. 과거 유지관리 시행 초기에는 보수보강 사례가 부족하였지만 현재는 수십년간의 축적된 자료를 바탕으로 제시된 산정식을 충분히 활용할 수 있을 것으로 판단된다. 향후 보수보강 효과를 정량화하는 방법에 대한 추가적인 연구가 수행된다면 더욱 경제적인 측면에서 우선순위를 산정할 수 있을 것이며 노후화된 기반시설 유지관리방안에 효과적으로 사용될 것으로 기대된다.

• Journal of the Korean Geotechnical Society
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• v.19 no.6
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• pp.325-334
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• 2003

It is very difficult to rehabilitate the damaged earth dam core to manage it stably against development of flow path and increase of leakage by hydraulic fracture. In this study, application of CGS (Compaction Grouting System) to damaged earth dam core was noticed by analyzing and comparing the results of the in-situ data and FEM. Results of in-situ data showed that according as progress of rehabilitation works tip pressures increased and volume of injection decreased, voids of damaged dam core were filled with materials similar to origin dam core. Rehabilitations caused turbidity and volume of leakage to decrease at the same water level. Also, results of FEM analysis indicated that permeability decreased by rehabilitation. Through this study, it is proved that CGS is able to decrease permeability coefficient, volume of leakage and turbidity on damaged earth dam core.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.3A
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• pp.349-356
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• 2008

Recently FRP (Fiber Reinforcement Polymer) is widely used for the strengthening of damaged RC beams. Although many tests were carried out to verify flexural capacity of RC beams strengthened with FRP sheet or plate, the behavior of strengthened RC beams has not yet clearly verified. To investigate the strengthening efficiency of the Near Surface Mounted Reinforcement (NSMR) technique experimentally and analytically, a total of 7 specimens have been tested. The experimental results revealed that specimens strengthened with NSMR improved the flexural capacity of RC beams. Also, while the NSMR specimens utilized CFRP reinforcement efficiently compared to the EBR (Externally Bonded Reinforcement) specimen, the NSMR specimens still have debonding failure between epoxy and concrete interface. This study has proposed the model to predict failure modes and failure loads. Good agreement was obtained between the predicted and the experimental results.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.6
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• pp.30-36
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• 2018

Researches on strengthening and rehabilitation are important since structural capacity is degraded by deterioration or damage of structural members. An effective strengthening scheme such as an externally bonded Carbon Fiber Reinforced Polymers (CFRP) can improve the structural performance of a concrete structure in a cost-effective way. Therefore, many experimental studies on strengthening methods have been widely carried out. In regards to the shear strengthening of a concrete beam, variables of the experimental studies were the amount of CFRP, the angle of the strip, the width of the strip, and the interaction between the materials. However, there are insufficient researches on bi-directional CFRP layout compared to the previous researches. In this study, a total of ten concrete beams were designed and tested to evaluate the shear strengthening effect using CFRP strips. The effectiveness of strengthening was investigated based on the shear contribution of materials, strain distribution of stirrup, and the maximum shear capacity of specimens.