• 한국산학기술학회논문지
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• 제19권5호
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• pp.167-175
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• 2018

정착구의 성능 평가를 위한 대부분의 기존연구와 성능실험들이 ETAG 013 규정에 따라 실험체를 제작하고 실험을 수행한 것으로 명시해오고 있다. 하지만 실험체에 사용된 파열력 보강 철근이나 보조보강철근이 ETAG 013에서 규정된 별도의 승인이 불필요한 최소 철근량을 초과 배치하여 실험이 수행되고 있다. 따라서, 본 논문에서는 ETAG 013 규정에 대한 올바른 이해와 실험을 위해 ETAG 013 규정에서 명시하는 하중전달실험 방법과 성능기준에 대해 고찰하고, 상용화된 PT정착구 시스템을 적용하여 고강도 콘크리트, 고장력 강연선을 변수로 한 실험체를 제작하고 하중전달실험을 수행하여 원형 정착구 시스템의 성능과 보조보강철근의 상관성을 평가하였다. 실험 결과, ETAG 013 규정이 적절한 크기 및 강도의 실험체와 파열력 보강철근을 사용하지 않으면 성능을 만족하지 않는 매우 엄격한 규정임이 확인되었으며, 보조보강철근의 양을 증가 시키는 것이 아니라 실험체의 크기를 최소치수로 한정짓지 않고 규정에 따라 15%크게 적용하는 방법으로 실험을 수행하는 것이 바람직한 것으로 평가되었다.

• 한국공간구조학회논문집
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• 제17권1호
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• pp.59-67
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• 2017

In this study, load transfer tests based on KCI-PS101 were conducted to verify the performance of spiral anchorage zone reinforcement for banded post-tensioning (PT) monostrands. With results, the compressive strength of spiral reinforcement was increased by about 20% than that of specimens with two horizontal steel bars and 8% than that of U-shaped bars. Advanced spiral reinforcement for corner increases compressive strength and can resist the spalling forces or fall-out effect at the corner by shear. The ratio of maximum load to amount of steel of the spiral reinforcement is about twice than that of U-shaped reinforcement. With increase of compressive strength capacity and improvement of constructability, the spiral reinforcement is considered to have advantages of promoting the performance of PT anchorage zone compared to conventional methods.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 봄 학술발표회 논문집
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• pp.167-172
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• 2000

In this study, the behaviors of a cast-in-situ concrete pile embedded in the weathered rock were analysed by a 3D numerical analysis using PENTAGON 3D and the results were compared with those of the field load test. The load-settlement relation and the load transfer relationship were evaluated from the numerical analysis. As a result, the load-settlement relation at the pile top and the axial load distribution with depth were predicted reasonably. And those results were similar with those of the field load test.

• 한국터널지하공간학회 논문집
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• 제18권5호
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• pp.487-497
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• 2016

터널을 굴착하면 굴진면 주변지반은 응력이 해방되고, 해방된 응력이 주변지반으로 재분배 되어 터널주변지반의 응력상태와 터널지보공에 작용하는 하중이 변한다. 굴진면에 변위가 발생하면 굴진면 전방지반이 이완되고 굴진면에 작용하는 토압은 감소하며, 변위가 일정한 크기 이상 커지면 굴진면 전방지반이 파괴상태에 이른다. 이때에 터널의 종방향으로 하중전이가 발생하며, 토피고나 굴진면의 변위정도에 따라 그 경향이 다르다. 굴진면 파괴에 따른 터널 종방향 하중전이에 대해서는 연구된 사례가 있으나, 굴진면 변위와 종방향 하중전이를 결부시켜서 연구한 사례는 거의 없는 실정이다. 따라서 본 연구에서는 토사터널에서 모형실험을 수행하여 굴진면이 과다변위로 인해 파괴됨에 따른 종방향 하중전이의 특성을 파악하였다. 즉, 정지토압 상태에서 시작하여 굴진면의 변위가 진행됨에 따른 터널 종방향 하중전이를 모형실험을 수행하여 측정하였다. 연구 결과, 종방향 하중전이는 굴진면 변위 초기에 대부분이 발생하고 굴진면 변위가 한계변위에 근접할수록 완만한 기울기로 한계치에 수렴하였다. 즉, 종방향 하중전이는 굴진면 전방지반이 아직 탄성상태일 때 급격히 증가하였고, 지반이 한계상태에 근접하면 완만하게 증가하는 경향을 나타내었다. 굴진면에서 변위에 의한 토압감소와 터널 종방향 하중전이는 같은 추세로 발생하는 것을 알 수 있었다.

• 한국지반공학회논문집
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• 제25권8호
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• pp.77-93
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• 2009

본 연구에서는 3차원 유한차분해석을 통하여 말뚝직경, 암반물성, 불연속면의 간격 및 방향 등 주요 인자가 암반근입 현장타설말뚝의 선단거동에 미치는 영향에 대한 분석을 수행하였으며, 이를 토대로 초기기울기 및 극한 단위선단지지력을 변수로 하는 쌍곡선형태의 선단하중전이(q-w)함수를 제안하였다. 제안식의 국내 암반지반에의 적용을 위하여 국내에서 수행된 14개 현장 23본의 시험말뚝의 재하시험자료를 토대로 제안식의 경험계수를 산정하였으며, 더불어 기존 초기기울기 및 극한단위선단지지력 산정식의 타당성 검토도 수행하였다. 현장재하시험 사례와의 비교분석 결과, 본 연구에서 제안된 산정식은 국내 암반지반에 근임된 현장타설말뚝의 선단거동을 비교적 잘 예측 가능하고, 말뚝지지력 및 침하량 예측값이 실측값에 가까움을 알 수 있었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2003년도 봄 학술발표회 논문집
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• pp.447-454
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• 2003

In this test, two separated oil jacks were placed at bottom of drilled shaft(D = 1,500mm, L = 33m), and maximum upward and downward load of 1,250 tonf was applied. Also, the deformable rod sensors were placed on each level, and axial strains at each level were measured. Because the side skin friction and the end bearing could be measured separately in the Osterberg type pile load test, this test might be more economical and more applicable than a conventional static pile load test. Thus, if this Osterberg type pile load test could be established during design stage, construction cost might be reduced and its application for large diameter pile could be enhance greatly.

• 한국환경과학회지
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• 제9권5호
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• pp.393-396
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• 2000

Packing tower has been used in the chemical industry and the protection of environment for a long time. In the view of environmental protection purification of exhaust gas can be performance effective by gas absorption in counter-current packing tower. In this study characteristics of hydraulic and mass transfer were investigated in D. $0.3m {\times} H. 1.4m$ packing tower with 50mn plastic Hiflow-ring. This study was carried out "Test systems were experimented in conditions of Air, $Air/H_2O. NH_3-Air/H_2O, NH_3-Air/H_2O-H_2SO_4$ and $SO_2-Air/H_2O-NaOH$ under steady state" The extent of test included dry and wetting pressure drop physical law separation efficiency and hold-up as function of gas and liquid load.quid load.

• 한국공간구조학회논문집
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• 제19권1호
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• pp.45-51
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• 2019

In this study, the static load test and the load transfer test were carried out to evaluate the structural performance of the circular anchorage proposed by the previous study. Specimens were fabricated according to KCI-PS101 and ETAG 013. As a result of the static load test, it was verified that the displacement of the wedge and the strand was kept constant when the tensile force of 80% of the nominal strength of the strand was applied. In the load transfer test, it was confirmed that all the specimens satisfied the stabilization formula of KCI-PS101 and ETAG 013. Post-tensioned one-way slab with circular anchorage were fabricated to evaluate the flexural behavior. All specimens exhibited the same flexural behavior and maximum load. However, the specimen with circular anchorage were advantageous than the rectangular anchorage one in terms of crack control of the anchorage zone.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2004년도 춘계학술발표회
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• pp.20-27
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• 2004

Reinforced twice than width of foundation with SIC under steel piles drived in cohesion soil and in the coal-limestone which heavily fractured. To analyze behaviour characteristic of steel piles, load transfer test was performed to steel piles attached with strain gauges to axial direction. After it passed 49days, dynamic load test was performed to set-up effect of steel piles bearing capacity. The results of test were compared to each other. According to the results, as the skin friction of steel pile was on the same condition, end bearing capacity of steel piles established on SIC solid of cemented milk in cohesion soil was three times than steel piles established on SIG solid of cemented milk in heavily fractured coal- limestone. After piles were driven and passes 49days, in case of piles on SIG solid of comented milk in cohesion soil the increaes of allowable bearing capacity was 442.9% and allowable bearing capacity of piles on SIG solid of cemented milk in heavily fractured coal-limestone increased 22.4%.

• Steel and Composite Structures
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• 제42권1호
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• pp.139-149
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• 2022

To simplify the design and reduce the construction cost of traditional multi-girder structural systems, twin I-girder structures are widely used in many countries in recent years. Due to the concern on post-fracture redundancy, however, twin girder bridges are currently classified as fracture critical structures in AASHTO specifications for highway bridges. To investigate the after-fracture behavior of such structures, a composite steel and concrete twin girder specimen was built and an artificial fracture through the web and the bottom flange was created on one main girder. The static loading test was performed to investigate its mechanical performance after a severe fracture occurred on the main girder. Applied load and vertical displacement curves, and the applied load versus strain relationships at key sections were measured. To investigate the load distribution and transfer capacities between two steel girders, the normal strain development on crossbeams was also measured during the loading test. In addition, both shear and normal strains of studs were also measured in the loading test to explore the behavior of shear connectors in such bridges. The functions and structural performance of structural members and possible load transfer paths after main girder fractures in such bridges were also discussed. The test results indicate in this study that a typical twin I-girder can resist a general fracture on one of its two main girders. The presented results can provide references for post-fracture performance and optimization for the design of twin I-girder bridges and similar structures.