• Journal of the Korea Concrete Institute
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• v.15 no.3
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• pp.470-481
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• 2003

Exterior plate-column connection has an unsymmetrical critical section for eccentric shear of which perimeter is less than that of interior connection, and hence, around the connection, unbalanced moment and eccentric shear are developed by both gravity load and lateral loads. Therefore, exterior connection is susceptible to punching shear failure. Current design provision cannot accurately explain strength of existing experiments, partly due to the complexity in the behavior of exterior plate-column connection, or partly due to the theoretical deficiency of the strength analysis model adopted. In the present study, nonlinear finite element analyses were performed for exterior connections belonging to continuous flat plate. For each direction of lateral load, the behavior and strength of exterior plate-column connection were quite different. Based on the numerical result, strength prediction model for exterior connection was proposed for each direction of lateral load. Compared with existing experiments, the proposed method was verified.

• Advances in concrete construction
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• v.2 no.1
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• pp.57-75
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• 2014

This paper presents an analysis of the results of an experimental program on the performance of a novel configuration of a hybrid FRP-concrete beam. The beam section consists of a GFRP pultruded profile, a CFRP laminate, and a concrete block all wrapped up using filament winding. It was found that the thickness of the concrete block and the confinement by the filament-wound wrapping had a profound effect on the energy dissipation behaviour of the beam. Using a shear punching model, and comparing the predicted results with the experimental ones, it was found that beyond a given value of the concrete block thickness, the deformational behaviour of the beam shifts from brittle to ductile. It was also found that the filament-wound wrap had many benefits such as providing a composite action between the concrete block and the GFRP box, improving the stiffness of the beam, and most importantly, enhancing the load carrying ability through induced confinement of the concrete.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.173-178
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• 2002

Flat plate is susceptible to punching shear failure at the slab-column connection, which may cause catastrophic structural collapse. To prevent such brittle failure, strength and ductility of the connection should be ensured. However, since it is very difficult to experimentally simulate the actual load and boundary conditions of the flat plate system, it is not easy to obtain reliable information and data regarding to the strength and ductility of the flat plate-column edge connection. In the present study, numerical studies were performed for edge connections of continuous flat plate. The results were compared with the existing experiments, and the variations of bending moment, drift, effective width around the connection were investigated. Based on tile findings of the numerical studies, the disadvantages of current design methods were discussed.

• Proceedings of the Korea Concrete Institute Conference
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• 1993.04a
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• pp.169-175
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• 1993

Possibility of fatigue failure in punching shear of reinforced concrete decks of highway bridges is analytically investigated by applying Matsui et al.'s experimental finding to models of 2-meter span decks designed in compliance with previous and current codes. Decks made of concrete of compressive strength of 240㎏/㎠ showed longer fatigue life than decks made of 210㎏/㎠ concrete at the same Md/U rations ; higher Md/U ratio resulted in linger fatigue life but its effect is insignificant in decks having effective depths of 14 and 15cm. Decks designed to higher load factors as specified by current codes showed longer fatigue life than decks designed to lower load factors specified by previous codes ; yet fatigue failure appeared to occur in both decks within their normal life span, thus indicating need for redefining the minimum deck thickness.

• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.33-36
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• 2009

현행 도로교설계기준의 바닥판에 대한 설계방법은 휨 이론에 따라 바닥판을 단위 폭의 보로 보고 강도설계법으로 설계하고 있다. 그러나 실제 교량 바닥판의 파괴 형태는 펀칭에 의한 파괴이므로 바닥판의 극한성능은 펀칭전단강도를 토대로 평가해야 할 것이다. 하지만 기존에 연구된 결과로는 초간편 강합성 바닥판의 펀칭전단강도를 산정하기 어려워 이에 대한 연구가 필요한 실정이다. 본 연구에서는 개발된 초간편 강합성 바닥판의 펀칭전단성능을 파악하기 위하여 초간편 강합성 바닥판과 RC바닥판에 대한 펀칭전단실험을 실시하여 비교하여 보았다.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.537-542
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• 1999

The design methodologies for carbon fiber sheet(CFS) strengthening of RC structures are not well established yet because the structural behavior of strengthened RC structures is more complex than that of unstrengthened ones. Even though the research for the methods using CFS has beed studied, the strengthening effects and structural behaviors of strengthened structures are not systematized yet. The purpose of this study is to carry out the experimental studies on three kinds of half scale RC slab bridges and to investigate the behavior of RC slab bridges from the experimental results. Typical flexural failure occurs in the non-strengthening slab like general RC slab bridges, and also the flexural failure occurs in the all area strengthened slab with sudden rip-off failure of strengthening material by punching shear. For the case of strip type strengthened slab, flexural failure occurs, with rip-off of second strip at the base of loading point. Strengthening effect on the slab using CFS is that the strength is increased upto 7~15 percent and the crack pattern is changed.

• Magazine of the Korea Concrete Institute
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• v.5 no.3
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• pp.116-124
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• 1993

지간 2ｍ인 RC바닥판을 모델로 하여 송정등이 연구한 실험결과를 기초로 피로파괴 가능성에 대하여 규명하였다. 같은 Md/Udptj 콘크리트 강도 240kg/$ extrm{cm}^2$이 210kg/$\textrm{cm}^2$보다 피로파괴 수명이 길게 나타나고, 유효높이 14,15cm는 Md/U를 크게 하여도 피로파괴수명에는 큰 증가가 없는 것으로 나타나고 있다. 같은 조건에서 92년판 시방서에 의해 설계한 단면이 85년판 시방서에 의해 설계한 것보다 피로파괴수명이 약 50% 증가된 것으로 나타나고 있으나, 양 시방서에 의해 설계된 단면 모두 펀칭전단 피로파괴가 일어날 수 있으므로 바닥판의 최소두께를 조정해야 할 필요가 있다.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.409-410
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• 2010

Since the 1980s with the development of construction techniques over 100 floors above 50 floors of the skyscraper was in progress. The advent of high-rise buildings due to an increase in foundation thickness was inevitable. at the moment, construction period and economic efficiency can be improved from decrease of the foundation thickness.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.791-796
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• 2000

Purpose of this study is to analyze the characteristics and reinforcement effects of restored the RC bridge deck with small precast panel through static load tests and to provide the basic information for the damaged slab decks. In the tests for realizing movement of general RC bridge slabs, 6 samples are prepared and tested. All reinforced samples are restored with 1 or 2-layers precast panels by epoxy mortar. The movement of restored slabs is analyzed and compared with the behavior of non-restored slabs. In result of these tests, tension cracks due to bending moment are show, and after static load test there happens finally a punching shear failure, which is the general type of RC bridge failure. The tests show that restoration of the RC slab results in increasing of loading capacity about 30~50% an restoring panels are stick to slab and moving with slab under loading test.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.415-420
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• 2003

This Study is performed to analyze the behavior of inverted T-shaped Composite Basement Wall(CBW). For this, it is purposed to analyze the failure mechanisms of inverted T-shaped composite basement wall and propose the method of evaluating strength for design. The failure mechanisms would be devided into 4 type mechanisms from previous experimental results, that is hanger failure, punching shear failure, flexural failure and the buckling of H-pile. A strength evaluation procedure for CBW is induced by analyzing respective failure mechanism. Then, the strength for actual structure consisted of inverted T-shaped composite basement wall was evaluated and the expected failure mechanism was determined.