• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.1
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• pp.183-192
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• 2008

Generally, application of steel pipe pile as deep foundation member needs special requirement for the connection method between steel pipe pile and concrete footing. Even though two types of connection method are suggested in the korea highway bridge code, type-B method is prevalent. In this study, vertical, lateral, and tension loading test are done for two types of type B connection to review stress concentration, formation and behavior of imaginary RC column in the footing. Welding type and hook type as the connection method are considered in this study. Test results show that welding type have the more reserve capacity than hook type and the specimens connected by the welding type behave as the imaginary RC column in the footing. However, the specimens connected by the hook type did not behave as the imaginary RC column in the footing but behave as the hinge.

• Journal of the Korea Concrete Institute
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• v.19 no.4
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• pp.401-409
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• 2007

The objective of this research is to provide better knowledge on the behavior of strong axis SRC column-RC beam joint, supported by experimental results, that can be broadly applicable to many structures. For this purpose, firstly literature reviews and field survey were made to classify the most commonly used for these types of joints. Then, experimental program was designed and performed including 6 SRC column-RC beam joint specimens designed with various joint details. Using the experimental results obtained from the quasi-static cyclic tests, structural performances of the joints such as hysteretic curves, maximum strength capacities, strength degradation beyond the maximum strength, ductilities, and energy dissipation capacities were investigated. Test results showed that specimens with wide beam shape (RCW-P, RCW-W, RCW-F) and T beam shape (RCT-W) showed better structural performances than the bracket type specimens (HBR-L, HBR-S). These specimens also revealed to have higher strength capacities than the nominal design strength. However, H beam bracket type specimens (HBR-L, HBR-S) need further study both analytically and experimentally to verify the reason for unexpected structural performances.

• Journal of the Earthquake Engineering Society of Korea
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• v.11 no.5
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• pp.61-69
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• 2007

The main purpose of this study is to provide a basic information for the seismic capacity evaluation and the seismic design of low-rise reinforced concrete (RC) shear wall buildings, which are comprised of a pilotis in the first story. In this study, relationships between strengths and ductilities of each story of RC buildings with pilotis are investigated based on the nonlinear seismic response analysis. The characteristics of low-rise RC buildings with pilotis are assumed as the double degree of freedom structural systems. In order to simulate these systems, the pilotis is idealized as a degrading trilinear hysteretic model that fails in flexure and the upper story of shear wall system is idealized as a origin-oriented hysteretic model that fails in shear, respectively. Stiffness properties of both models are varied in terms of story shear coefficients and structures are subjected to various ground motion components. By analyzing these systems, interaction curves of required strengths for various levels of ductility factors are finally derived for practical purposes. The result indicates that the required strength levels derived can be used as a basic information for seismic evaluation and design criteria of low-rise reinforced concrete shear wall buildings having pilotis structure.

• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.1
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• pp.147-156
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• 2004

The Rehabilitation and repair of structurally deteriorated, reinforced concrete structures will be highly demanded in the near future. The purpose of this study is to investigate whether damaged beams that crack and deflection are developed by bending moment are restored to the former state. In conclusion, when specimens strengthened with Steel Plate, CFS(Carbon Fiber Sheet) and CFRP-Grid(Carbon Fiber Reinforced Plastic-Grid) are compared with standard specimen, flexural capacity is increased and ductility and energy absorbtion capacity are similar with undamaged specimen. Therefore Steel Plate, CFS(Carbon Fiber Sheet) and CFRP-Grid (Carbon Fiber Reinforced Plastic-Grid) have highly efficiency as material of flexural strengthening.

• Journal of Korean Society of Steel Construction
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• v.27 no.1
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• pp.63-75
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• 2015

In this study, Composite beam flexural capacity was investigated experimentally using angle as a shear connector. The main experimental parameters are the size and the spacing of the angle and the overall behavior of before and after composite. Also, the composite beam bending performance when it used with hollow PC slab and the general RC slab was compared. When determining that it synthetically, the flexural capacity of the composite beam with angle shear connector estimated 25% to 55% more strength than the nominal strength. Effects of strength parameters of composite beam by angles shear connector are size and spacing of the angle. As expected, the larger and the narrower spacing of the angles, the more strength the composite beam have. In addition, the performance of the composite beam with a hollow slab was well demonstrated by the test.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.08a
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• pp.39-39
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• 2020

호박(Cucurbita spp.)은 박과 호박속 식물로 원산지는 열대 남아메리카로 추정되며 1년생 혹은 다년생 초본으로서 우리나라를 포함한 전 세계에서 널리 분포하고 있다. 호박은 비타민A와 비타민C가 풍부하고 이뇨작용 효과가 탁월해 피부를 좋게 하고 부기를 빼주는 것으로 보고되고 있다. 본 연구에서는 농업유전자원센터에서 보유한 호박속 자원의 내력과 형태적인 특성을 그룹화하여 자원 활용을 위한 기초자료를 제공하고자 하였다. 농업유전자원센터에서 보유한 호박속 등록자원은 총 5종(C.pepo, C. moschata, C.maxima, C.argyrosperma, C .ficifolia) 1,640자원으로 주요 원산지는 한국 589자원(35.9%), 미국 122자원(7.4%), 러시아 79자원(4.8%), 멕시코 49자원(4.2%), 터키 56자원(3.4%)이었으며 국내 원산의 경우 강원도에서 수집된 자원이 66자원으로 가장 많았다. 전체 1,640 자원 중 재래종은 733자원(44.7%)을 차지하였으며 다음으로는 육성품종이 133자원(8%)으로 많았다. 생장형이 조사 된 301자원 대부분이 덩굴성이며 준왜성 16자원, 왜성 14자원이 있었다. 호박은 과실 모양과 색, 잎 모양, 줄기 모양 등 생육 특성이 매우 다양하게 조사 되었으며 과경 등 몇 가지 특징은 완벽하지 않지만 종(species)을 구분하는 간이적인 지표로 사용되는 것으로 조사되었다. 흰가루병 저항성 자원은 조사 된 1,170 자원 중 우리나라 재래종인 참호박(IT104575)을 포함한 7자원이 조사되었다. 293개 자원의 과실당도는 2.2~15.4brix까지 다양했으며 당도 12brix 이상 자원은 IT200650을 포함하여 6자원이 조사되었다. 본 연구에서 조사된 호박속 자원의 내력 및 생육 특성은 육종소재의 기초 정보로서 이용되고 있으며 자원 내력정보의 보완, 형질과 기능성 물질 분석 등 추가적인 연구를 통해 연구소재의 기초 정보로서 활용의 가치가 더 커질 것으로 보인다.

• Journal of Korean Society of Steel Construction
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• v.20 no.4
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• pp.483-491
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• 2008

There has been much focus on the strong axis steel moment connections after the Northridge earthquake in 1994. However, research studieson the seismic behavior of weak axis moment connections could be hardly found despite the fact that these connection details have been frequently used as seismic details of MRF in Korea. Therefore, the objective of this research is to provide better knowledge on the seismic behavior of weak-axis steel moment connections, which can be widely applicable to many structures with similar characteristics. For this purpose, an experimental program was designed and performed with twotypes of weak-axis steel moment connections, namely the bracket type and WUF-B type, based on the survey of existing field data and literatures. Using the experimental results obtained from the quasi-static cyclic testing of these specimens, structural performances of the joints such as hysteretic curves, maximum strength capacities and the strain of reinforced bars were investigated. From the test results, the bracket-type connection was shown to have more than a 5% story drift capacity, compared with the WUF-B type connection's 4%. These specimens were also shown to have higher strength capacities than the nominal design strength. The bracket-type connection showed a slow strength degradation after maximum strength was researched. However,the WUF-B type connection showed a rapid strength degradation that caused brittle behavior.

• Magazine of the Korea Concrete Institute
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• v.6 no.6
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• pp.190-198
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• 1994

Th~s paper presents the shear behavior in reinforced normal, medium and high strength con crete beams due to the Increase of concrete compressive strength. Twelve shear tests were con ducted on full scale beam speclrnerls havmg concrete compressive stlengths of 360, 670 and 873kg/$cm^2$. Different amounts of shear reinforcement as a variable were investigated according to ACI 318 89. The shear responses are discussed in terms of the shear capacity. the ductility and the reserved strength. The prediction and comparison with the test results are also presented.

• Journal of the Earthquake Engineering Society of Korea
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• v.15 no.6
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• pp.45-53
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• 2011

The purpose of this study was to propose a design procedure for a damped structure with a friction damper for an existing structure. The target displacement of the damped structure was determined using the maximum displacement of the existing structure. The displacement of the damped structures was predicted using a proposed equation for the inelastic displacement ratio. For this study, we conducted a nonlinear response history analysis using 80 earthquake ground motions to verify the validity of the proposed design procedure by comparing the responses of the damped and undamped structures. Based on the dynamic analysis results, it was concluded that the predicted displacement of the damped structure using the proposed design procedure matched well with the analysis results.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.326-329
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• 2006

Strengthening method using CFS have been developed for the rehabilitation of structures. However, it is very difficult to estimate their resistance capacity after retrofit. Therefore, damage information for strengthened structure with CFS investigated and the estimation method structural capacity by using the damage information is developed. The final objective of this research work is to propose the guideline and method for resistance capacity estimate of structure. In this paper, experimental study result with test parameters of number of carbon fiber sheets and bonding ratio is introduced.