• Journal of the Computational Structural Engineering Institute of Korea
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• v.34 no.2
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• pp.93-100
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• 2021

In Korea, one of the most used structural systems for residential apartment buildings is the combination of the reinforced concrete (RC) wall and rahmen structures in the upper and lower floors, respectively. To alleviate the significant difference between the stiffnesses of these two structural systems, large transfer girders are generally required in the transition zone of the structure, which then results in the use of large amounts of construction materials and low economic feasibility. This paper proposes a new RC boundary-beam-wall system that can minimize the disadvantages of the RC transfer girder system. The structural performance of the proposed system subjected to axial loading was evaluated via rigorous three-dimensional nonlinear finite element analysis. Four parameters, namely the ratio of lower wall to upper wall lengths, distance between stirrups, main bar slope ratio, and slab length, were considered in the finite element analysis, and their effects on the maximum axial load were analyzed and discussed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.1
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• pp.183-189
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• 2006

When RC structures are repaired or strengthened using FRP, it is required to cure for some Period under certain air temperature and then it is hopeful to avoid detrimental action caused by external vibration sources during that period. Therefore, an effect of repeated loading during Carbon Fiber Sheet(CFS) strengthening Process on the strengthening efficiency is studied through an experiment for a number of RC beams. Experimental results showed that the curing time of 24 hours without any repeated loading after CFS attachment were recommended for 1 ply strengthening, and 12 hours for 2 plies strengthening.

• Journal of Korean Association for Spatial Structures
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• v.12 no.1
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• pp.51-58
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• 2012

A model for the nonlinear flexural analysis of extruded Engineered Cementitious Composite (ECC) panel reinforced concrete (RC) composite slab has been newly presented. From direct tensile test, ECC panel has been modeled to have the high-ductile tensile behavior after cracking. The developed model was compared with bending test results of two specimens, a conventional RC slab and a ECC panel RC composite slab. The predicted results were well patched with the experimental results, and the ECC panel RC composite slab system had advantages in crack control and improving flexural load-carrying capacity and deformation-capacity.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.2
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• pp.153-160
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• 2010

The widespread deterioration of concrete structures has required the development of new and innovative materials and technologies for strengthening and repair. Recently Fiber reinforced polymer(FRP) composites have received widespread attention as materials for the strengthening and repair of the deteriorated concrete structures. This paper presents the results of Fire-performance of RC beams strengthened with FRP-Aluminum composit hollow beams. Test results show that the higher-damaged FRP strengthened RC beams are more vulnerable to the fire and decrease the effect of FRP strenthening.

• 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 Korean Society of Steel Construction
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• v.25 no.6
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• pp.623-634
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• 2013

In this study, the structure behavior of RC slab and SC shear wall connection was investigated. Also experimental study was performed to evaluate the factor of safety of demand shear connection strength in KEPIC SNG Standard. As a result, shear friction strength of connection was known about 300kN and shear strength of rebar increased according to the displacement increase. With the installment of the lower rebars, 40% shear strength increased compared to the non-rebar specimen.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.123-128
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• 2002

In this paper, an averaged constitutive model of concrete and reinforcing bars for RC structure and path-dependent Ohsaki's model for soil are applied, and an elasto-plastic interface model having thickness is preposed for seismic analysis of underground RC subway station structure. A finite element analysis technique is developed by applying aforementioned constitutive equations and verified through seismic analysis of underground RC subway station. Then, failure mechanisms of the RC subway station structure under seismic action are numerically derived. Then, failure modes and damage levels of the station are also analytically evaluated for the cases of several designs of the underground RC station.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.12 no.3
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• pp.475-484
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• 1999

압력절점은 요소의 균등한 압력증분을 1개의 자유도로 갖는 절점이며, 유한요소의 하중-변위 평형방정식에 체적과 압력의 관계를 추가하여 한계압력 이후에서도 체적변화에 따른 압력증분을 직접적으로 제저할 수 있는 절점이다. 본 연구에서는 철근콘크리트의 평면 구성 방정식과 적층정식화에 적용한 쉘 요소에 압력절점을 추가하고 해석시 체적을 제어함으로써 철근콘크리트 원통형 구조에 대해 파괴까지의 극한내압 능력을 해석할 수 있는 체적제어 비선형 해석기법을 개발하였다. 본 논문에서 제안한 해석기법을 이용하여 철근콘크리트 원통형 구조물에 대하여 비선형 해석을 수행하여 한계압력과 한계압력 이후의 구조물의 거동을 예측하였으며 실험결과와 비교 검증하였다.

• Journal of the Society of Disaster Information
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• v.10 no.2
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• pp.312-318
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• 2014

Recent building structures are superior in its ability but they are light weight and long span, and so have problems of vibration. In general, the serviceability of RC slabs was known to be good against vibration because of its hardness. However, recent high-rise apartment slabs are mostly light and long, the serviceability of RC slabs due to vibration could be a problem. In this paper, a basic investigation about vibration problems of RC slabs was performed. Basic information and its influence on vibrations of RC slabs were revealed. Also, its serviceability against vibration was examined. Many tests were conducted for natural frequency of building, for example load of two persons walking and one person leaping etc.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.6
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• pp.155-162
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• 2012

When RC (Reinforced Concrete) structures are exposed to sea water, steel corrosion can occur and this leads a degradation of structural performance. Referring the electro-deposition system with sea water from the 1st step research, durability and structural performance are evaluated in coated steel and RC members containing it in the 2nd research. In the durability performance test, Half Cell Potential test is performed and the coated steel is evaluated to have the high resistance to corrosion, which shows only 35% of corrosion velocity in normal (bare) steel. In the structural performance test, tensile strength, adhesive strength, and flexural/shear in RC member are performed. For the electro-deposit coated steel, increasing ratios of 3.2% and 8.8% are evaluated in the test of tensile strength and adhesive strength, respectively. For the structural test in RC member, there is no big difference between RC members with coated and non-coated steel in ultimate load and failure pattern It is evaluated that the chemical compound with $CaCO_3$ and $Mg(OH)_2$ from electro-deposition causes slightly increased structural performance. The electro-deposit coated steel can be more widely applied after performance verification from several tests like fatigue, resistance to impact, and long term-submerging test.