• Journal of the Korean Geotechnical Society
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• v.21 no.5
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• pp.111-122
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• 2005

The data on the pile load tests performed on 35 large drilled shafts are analyzed to investigate the load-settlement characteristics of large drilled shafts embedded in bed rocks. Generally, the settlement of large drilled shafts embedded in bed rocks is too small to determine the ultimated load with application of the regulation in design code for either the total settlement or the residual settlement. Therefore, to determine the yield load of large drilled shafts embedded in bed rocks, p(load)-logS (settlement) curve method, which has been proposed originally for the driven pile, was applied to the investigation on the data of the pile load tests. This technique shows that the yield load can be determined accurately and easily rather than other conventional techniques such as P-S, logp-logS, S-logt, and P-S curve methods. An empirical equation is proposed to represent the relationship between pile load and settlement before the yield loading condition. And the settlement of piles was related with the depth embedded in rock as well as rock properties. Based on the investigation on the data of pile load tests, the resonable regulations f3r both the total settlement and the residual settlement are proposed to determine the yield load of large drilled shafts embedded in bed rocks.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.9
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• pp.4216-4222
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• 2011

In this study the inelastic behavior of the existing school buildings with infilled masonry walls is analysed by pushover method. The shear stiffness and strength of masonry wall is calculated from the prior experimets and verified by inelastic analysis. The height of infilled masonry wall affects the structural behavior. The higher the masonry wall height, the higher the initial shear stiffness and strength of masonry wall. As the cracks are developed, the strength of masonry wall is much decreased. The proposed inelastic analysis method shows similar results with the experiments and can be used as inelastic analysis model of reinforced concrete buildings with infilled masonry walls.

• Journal of the Korean Geosynthetics Society
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• v.12 no.4
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• pp.99-107
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• 2013

In order to investigation Lateral bearing capacity of bored-precast pile, we carried out the analysis of the relationship between Lateral load and horizontal displacement using the result of horizontal pile load test. The six piles injected cement milk of 50%, 70% and 100% of the embedded length of pile were used in the horizontal pile load test. The horizontal displacement, yielding load and horizontal bearing capacity are mainly affected by The injecting ratio of cement milk (injected length of cement milk/embedded length of pile). As the injecting ratio of cement milt is increased, the starting point of horizontal displacement in piles become close to the ground surface and the amount of horizontal displacement is decreased. Also, the horizontal bearing capacity and yielding load are highly increased with increasing the ration of cement milk. The horizontal bearing capacity and yielding load of bored pile with 1 of cement milk ratio are about two or three times those of pile with 0.5 of cement milk ratio.

• Journal of Korean Society of Steel Construction
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• v.20 no.2
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• pp.247-258
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• 2008

In this study, static loading tests were performed on H-beam specimens to assess the static behavior of H-beam prestressed with multi-stepwise thermal prestressing method (TPSM). The amount of induced thermal prestress and connection type were differentiated among the 400-mm-high and 6,000-mm-long H-beam specimens to evaluate their effect on the behavior of the beams. From the experimental results, it between the H-beam and the cover-plate increased in yielding load by 13~18%, whereas stiffness increased by 27~34%. In case of specimens with both bolting and welding connection, yie lding load increased by 18~29% and stiffness increased by 43~51%. Multi-stepwise initial stress distribution was also observed from the prestressed specimens, verifying the effectiveness of the multi-stepwise TPSM. By application of the multi-stepwise TPSM, a significant increase in yielding load and stiffness can be achieved, hence increasing sectional and prestressing efficiencies.

• Journal of the Korean GEO-environmental Society
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• v.14 no.3
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• pp.29-34
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• 2013

In this paper, numerical analyses were conducted on piled raft foundation settlement and pile bearing characteristics in soft ground. Results obviously showed longer and larger piles developed end bearing capacity values, but also showed the load of the central pile is larger than the surrounding piles in a group formation. Additionally, after pile yielding, the load carrying capacity exists as a raft. Moreover, results showed no transverse displacement according to embedment depth for the single pile case, but larger transverse displacements for deeper embedment depths.

• Journal of Korean Society of Steel Construction
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• v.11 no.1 s.38
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• pp.43-54
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• 1999

The divergence connection between steel circular tubes is widely used in such structures as factory facilities, steel circular hollow section truss, and off-shore tower. Steel circular hollow section (SCHS) have close section, and it makes their per-unit production expense higher than open sectioned products like L-shape, H-shape steels, but the sectional resistance of SCHS against vertical compression and torsion is very high. Despite the structural merits of SCHS, however, many engineers dislike to use them in their design because of uncertainty regarding the stress distribution and deformation behavior at their connections. Therefore, this thesis dealt with X-type connections, the most common forms of connection, and studied their load-deformation relationship. It observed how to show the load-deformation relationship at steel circular tube connections according to the diameter-thickness ratio (D/T) of the chord and diameter of branch-diameter of chord ratio (d/D) and suggested prediction yield load using by ring analysis method.

• Magazine of the Korean Society of Agricultural Engineers
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• v.26 no.1
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• pp.38-51
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• 1984

Mononobe-Okabe에 의해서 옹벽에 대한 동적 토압계산법이 개발된 이래 본론두중 옹벽의 과동에 의한 변위에 대해서는 많은 연구가 이루어졌으나 Mononobe-Okabe식이 원래 옹벽 자체의 관성을 고려치 아니하였고 또 동적 하중의 작용점을 제시하지 않으므로서 전도모멘트를 계산할 수 없게 하므로서 옹벽의 전도에 의한 변위에 대해서는 연구가 되지 아니하였다. 본 연구의 목적은 해석적 방법과 모형실험을 통해서 지진 및 폭파 등의 동적 하중에 의한 옹벽의 전도에 의한 변위를 고찰하고자 하는 바 그 결과를 요약하면 다음과 같다. 1. 활동에 대한 항복가속도가 있는 것과 마찬가지로 전도에 대한 항복가속도가 있다. 이 항복가속도는 옹벽의 안전율이 증가함에 따라 증가한다. 2. 이론치와 실험치는 경향으로 보아 일치한다. 실험치가 이론치보다 작은 것은 모형실험에서 옹벽측면과 컨테이너 사이의 마찰에 기인한 것으로 보아지며 마찰을 줄임으로써 이론치에 더 접근시킬 수 있을 것이다. 3. 옹벽의 회전각도의 크기는 지반가속도가 클수록, 옹벽저면이 작을수록 그리고 흙의 내부마찰각이 작을수록 크게 증가한다. 4. 실용적인 규격의 옹벽의 변위는 활동에 의한 것보다 전도에 의한 것이 훨씬 크며 전체 변위의 대부분을 차지한다. 5. 옹벽 상단의 횡적 변위는 옹벽 설계를 결정짓는 중요한 요소가 될 수 있다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.3
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• pp.223-230
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• 2003

The purpose of this research are to investigate experimentally flexural strengthening effects and flexural behaviour of RC beams strengthened by carbon fiber sheet(CFS) with/without superimposed pre-load. Test parameters of experiment are tension reinforcement ratio(0.85, 1.32, 1.91%) and pre-load(80% of yield capacity of unstrengthened beams). The structural behaviour of strengthened beams are compared with in terms of yield load and ultimate load, load-deflection relation, ductility, strengthened efficiency. From the test results, it were shown that ultimate capacity and flexural failure behaviour of RC beams strengthened by CFS changed by initial stresses between original beams and bonded CFS.

• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.3
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• pp.177-187
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• 2004

This investigation attempts to analyze the flexural behavior of a strengthened beam with carbon fiber sheets in three stages according to the conditions of the constituents : elastic stage, pre-yielding stage, and post-yielding stage. The proposed analytical method for strengthened beams is compared with the experimental results such as yield load, ultimate load, and flexural rigidities. The contributions of the constituents to the strengthened beam capacity are examined from the flexural analysis. The validity of using KCI strength method to estimate ultimate moment of a strengthened beam is also investigated.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.285-291
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• 2016

The purpose of this study was to evaluate the structural capacity of steel pipe pile specimens reinforced with hollow steel plate shear connectors by pull-out test. Compressive strength testing of concrete was conducted and yield forces, tensile strengths and elongation ratios of re-bars and hollow steel plate were investigated. A 2,000kN capacity UTM was used for the pull-out test with 0.01mm/sec velocity by displacement control method. Strain gauges were installed at the center of re-bars and hollow steel plates and LVDTs were also installed to measure the relative displacement between the loading plate and in-filled concrete pile specimens. The yield forces of the steel pipe pile specimens reinforced with hollow steel plate shear connectors were increased 1.44-fold and 1.53-fold compared to that of a control specimen, respectively. Limited state forces of steel pipe pile specimens reinforced with hollow steel plate shear connectors were increased 1.23-fold and 1.29-fold compared to that of a control specimen, respectively. Yield state displacement and limited state displacement of steel pipe pile specimens reinforced with hollow steel plate shear connector were decreased 0.61-fold and 0.42-fold compared to that of a control specimen, respectively.