• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1994년도 봄 학술발표회 논문집
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• pp.19-24
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• 1994

Four types of horizontal joint were tested to investigate the difference with regards to the compressive behavior and strength. These include wedge-type joints (i)with and (ii)without transverse reinforcement against splitting failure of the panel concrete, and wedge-type joints (iii)with different widths of joint concrete (6cm vs 8cm) and (iv)closed platform joint. It was shown that the compressive strength of wedge-type joint is about 10% higher than that of closed-type (platform) joint. But the effect of transverse reinforcement and joint concrete widths on the strength of the joints turned out be negligible. Also, the moduli of elasticity in panel and joint are compared and the equivalent moduli of the whole wall are derived.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.623-628
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• 2001

The objective of this study is to find out the effect of Horizontal vibration on the compressive strength for 7 days and 28 days cured concrete specimens according to the kind of fine aggregates and the variation of vibration velocities, and times began to vibrate. Three kinds of fine aggregate(river sand, sea sand, crush sand), three types of vibration velocities(0.25, 0.5 0.1kine(cm/sec)), and four steps of times(0, 3, 6, 9 hours after concrete casting) were chosen as the experimental parameters in this study, the vibrations are applied for 30 minutes in each case. From this study, the variation with type of fine aggregate doesn't show tendency and the compressive strength decreases with increasing vibration velocity. When the vibration force time is more than 6 hour, It shows that compressive strength decreases under the condition of vibration velocity which the value is 0.5 kine and 1 kine, respectively.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.770-773
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• 2004

The full-width, full-depth precast panel system is very efficient for the rehabilitation of deteriorated decks as well as for new bridge construction.. The horizontal bond strength at the interface between the two interconnected elements is of primary importance in order to achieve composite action. The strength of the bond between the two precast members should be high enough to prevent any progressive slip from taking place. However, the case when both of the interconnected elements are precast members bonded by means of grout, is not currently addressed by KBDC or AASHTO. This is the main impetus for this study. A total 43 push-off tests were performed to evaluate the horizontal bond strength and to recommend the best practice for the system. Test parameters included different interface surface conditions, different amount and different types of shear connectors. The presence of the shear keys at the top surface of the beam increased the interface bond capacity tremendously compared to the bond capacity with a different surface conditions.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1995년도 가을 학술발표회 논문집
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• pp.198-203
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• 1995

The objective of this study is to provide the information on the techniques of manufacturing and experiment in small scale modeling of precast concrete(P.C.)large panel structures. The adopted scale was 1/5th 4types of experiments were performed : material tests for model concrete and model reinforcement, compressive test of horizontal joint, shear test of vertical joint and cyclic static test of 2-story subassemblage structure. Based on the experimental results, the following conclusions are drawn: (1)Model concrete may have in general larger compressive strength than expected. (2) Model reinforcement can show less ductility if the annealing processes were performed without using vaccuum tube. (3) Failure modes of horizontal and vertical joints were almost same for both prototype and model. But the strength of model appears to be higher than required by similitude law. (4)Hysteretic behavior of 1/5 scale subassemblage model can be made quite similar to prototype's if the ductility of model reinforcement and compressive strength of model concrete could be representative of those of prototype.

• 대한인간공학회지
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• 제9권2호
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• pp.3-9
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• 1990

The paper concerns with the visual illusion strength for the static and dynamic figures which are generated on computer CRT. The Vertical-Horizontal, Ponzo, and Muller-Lyer illusion are studied under various conditions of type, size, and background angle of figure. And the results are obtained through the Multivariate Analysis of Variance (MANOVA). This paper concludes that the size and background angle of figure generally effect on the visual illusion, and there is a significant difference between figure types. These results can be applied to eliminate the visual illusion in real design.

• 한국강구조학회 논문집
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• 제16권2호통권69호
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• pp.275-284
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• 2004

기둥-보 약축 접합 디테일 개발을 위해서 접합부의 거동을 파악하는 것이 선행되어야한다. 약축 접합부의 형식에 따른 강축 접합부의 거동을 파악하기위하여 기존 브라켓타입 용접접합부의 각 요소들 즉 패널존, 수평스티프너의 유무 및 위치를 변수로 고려하였다. 본 연구에서는 접합부에 수평스티프너가 있는 경우는 접합부를 수직스티프너로 보강한 단순보로 치환하여 접합부의 내력을 산정하였으며, 수평스티프너가 없는 경우는 기둥플랜지의 국부휨강도, 기둥 웨브의 국부인장강도, 기둥 웨브의 크립플링강도 및 기둥웨브의 최대 좌굴강도를 고려한 내력 평가식을 사용하였고 이론해석결과와 실험결과를 비교 분석하였다.

• 대한토목학회논문집
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• 제29권5A호
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• pp.511-518
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• 2009

본 연구에서는 콘크리트와 철근과의 부착강도에 영향을 미치는 요인 중 철근의 위치를 수평하부철근(Horizontal reinforcement at Bottom position, HB), 수평상부철근(Horizontal reinforcement at Top position, HT), 및 수직철근(Vertical reinforcement type, V)으로 변화시킨 시험체를 제작하여 3수준의 콘크리트 강도 변화(30, 50 및 70 MPa)에 따른 고유동 자기충전 콘크리트(High flowing Self-compacting Concrete, HSCC) 및 일반콘크리트(Conventional Concrete, CC)와 이형철근의 부착 특성을 비교 분석 하였다. HSCC 및 CC의 상부근 철근계수를 평가하기 위하여 HB/HT 철근의 부착강도비를 측정한 결과 50 및 70 MPa의 경우 HB/HT의 부착강도비는 1.3이하로 나타났으며, 30 MPa의 경우 HSCC 및 CC에서 각각 1.2 및 2.1로 나타났다. 따라서 HSCC 30, 50 및 70 MPa의 경우 콘크리트구조설계기준(2007) 정착길이 설계시 상부근 계수에 제시되는 수평상부철근에 대한 정착길이 보정계수를 CC의 1.3보다는 감소시켜 적용하는 것이 바람직할 것으로 판단된다.

• 한국지반공학회논문집
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• 제34권3호
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• pp.67-75
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• 2018

본 연구에서는 상부하중 재하 시 마이크로파일 선단부가 팽창하면서 확대되어 단부 주변 지반을 압축하고, 이에 따라 주면마찰력이 발휘되어 그라우팅 이전 단계에서도 지지력을 확보할 수 있는 고정지압구가 장착된 마이크로파일을 개발하였다. 본 연구의 목적은 개발된 고정지압구형 마이크로파일의 지반강도에 따른 적용성을 확인하고, 기존의 단순 선단확장형 마이크로파일 대비 지지거동 특성을 비교하는 데에 있다. 이를 위하여 선단저항과 주면저항을 분리하여 측정할 수 있는 모형토조를 포함한 새로운 시험장치를 고안하였으며, 고안된 시험장치를 이용한 지반강도 및 파일의 선단단면 변화에 따른 모형 재하시험을 수행하였다. 시험결과, 개발된 마이크로파일은 지반강도가 클수록 쐐기수평력에 의한 단부 주면마찰력이 더 증가하며, 풍화암 강도 이상 지반에서 더 효과적으로 적용될 수 있는 것으로 확인되었다. 그리고 풍화암 강도 이하의 지반강도 지반에서도 쐐기수평력 발휘에 따른 단부 확경으로 인해 추가적인 지지력 확보 효과가 나타날 수 있음을 확인하였다.

• Structural Engineering and Mechanics
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• 제32권4호
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• pp.531-547
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• 2009

This paper presents the experimental results on the strength behavior and failure modes of box beam-to-circular column connections in steel piers. Previous research introduced parameters such as joint central angles, extension of horizontal stiffeners, and use of equivalent web depth, which ignored strength behavior and failure modes of box beam-to-circular column connections. The use of equivalent web depth $d_2$ is not reasonable when central angle ${\alpha}$ is closer to $90^{\circ}$; therefore, a monotonic loading test has been performed for eight connection specimens. From the test, it is identified that the connection with the circular column is stronger than the connection with the box-sectioned substitution column. Also, the strength of the beam-to-column connections with horizontal stiffeners is higher than the one of the no column stiffeners. The concrete-filled effect of box beam-to-circular column connection is also investigated, and the experimental yield strength of the connection is compared with the theoretical one. Also, more a reasonable equivalent web depth is suggested. The failure modes of connection are clearly defined.

• 한국정밀공학회지
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• 제23권8호
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• pp.154-162
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• 2006

By laying its drum horizontally, front-loaded washing machine mostly used in Europe that uses the head of the water to launder was appropriate for washing only small amount of laundry. However, the demands of customers are requiring front-loaded washing machine to handle big capacity laundry as well, and have faster rotation speed to increase drying ability. To meet such demands, more stress from bending and twisting are complexly loaded onto the shaft supporting the horizontal drum, causing problems in fracture strength and fatigue life. Shafting system is mainly divided into flange and shaft. Flange is located between the drum and shaft, transferring power from the shaft to drum, and acting as a supporter of the back of the drum. Shaft is connected from the flange to insert production, transferring power from the motor to drum, and mainly acting as stiffness against the horizontal weight of the shafting system. In this paper, strength analysis and experiment were executed on both the shaft and flange of front-loaded washing machine to suggest the design improvement of shafting system for big capacity, high-rotation drying. Also, verification of this evaluation was executed on fracture strength and fatigue life for studied shaft system.