• 콘크리트학회논문집
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• 제11권5호
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• pp.107-118
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• 1999

10 RC bridge piers have been made on a 1/3.4 scale model, and six piers of them were retrofitted with glassfiber. The have been tested in the quasi-static cyclic load so as to investigate their seismic enhancement before and after retrofitting with glassfibers. The objective of this experimental study is to investigate how to strength the ductility of reinforced concrete bridge piers which have been nonseismically designed and constructed in Korea before 1992. Important test parameters are axial load, load pattern, retrofit type. Glassfiber sheets were used for retrofitting in the plastic hinge region of concrete piers. The nonlinear behavior of bridge columns have been evaluated through their yield and ultimate strength, energy dissipation, displacement ductility and load-deflection characteristics under quasi-static cyclic loads. It can be concluded from the test that concrete piers strengthened with glassfibers have been enhanced for their ductile behavior by approximate 50%.

• 한국지진공학회논문집
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• 제3권2호
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• pp.55-66
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• 1999

본 연구는 철도, 도시고속화도로 및 고속도로 교량의 교각으로 많이 이용디고 있는 철근콘크리트 기둥으 내진성능 평가에 관한 quasi-static 실험으로서 사용된 실험 변수는 축하중 내진설계유무에 따른 띠철근량 변위제어 하중형태 등을 채택하였다 RC 기둥시험체는 수원에 위치한 하갈교의 교각을 1/3.4의 축소모델로 하여 내진설계된 단면과 내진설계되지 않은 시험체를 각각 4개씩 총 8개를 제작하였으며 소성힌지구간에서 띠철근의 간격은 2.2cm 및 4.4cm 이다 실험변수에 따른 내진 및 비내진 시험체의 내진성능검토를 위하여 충진콘크리트 교각의 하중변위 이력특성 연성능력, 강도감소, 에너지 흡수능력, 등가점성계수 등을 실험적으로 분석조사하였다. '96년 개정된 도로교시방서의 RC기둥에 관한 내진설계기준은 AASHTO(1992)와 유사한 것으로서 중.약지진 지역으로 구분되는 국내의 실정에는 다소 과다설계로 판단된다. 실험결과 비내진설계된 콘크리트 교각도 어느 정도의 연성능력을 발휘한 것으로 조사되었으나 추가의 충분한 실험연구가 요구된다. 그러나 비내진설계교각도 적절한 내진보강방안을 강구한다면 우수한 내진성능을 발휘할수 있으리라판단된다.

• 한국안전학회지
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• 제13권3호
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• pp.11-23
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• 1998

In this study, collapse test of thin-walled structure is performed under axially quasi-static and impact load in collapse characteristic to develop the optimum structural member for a light-oriented automobile. Furthermore, the energy-absorbing capacity is observed according to the variety of configuration(circular, square), aspect ratio in aluminum specimen to obtain basic data for the improved member of vehicle. In both quasi-static and impact collapse test, Al circular specimens collapse, in general, with axisymmetric mode in case of thin thickness while collapse with non-axisynmetric mode according to the thickness increase. For Al rectangular specimens, they collapse with axisymmetric mode in case of thin thickness, with mixed collapse mode according to the increase of thickness. In terms of initial max. load, Al square specimen turns out the best member among specimens, and then Al square, circular and circular with large scaling ratio, respectively. In case of quasi-static compression test, the absorbed energy per unit volume and mass shows higher in Al circular specimen, and then Al square, circular with large scaling ratio, respectively, according to shape ratio the absorbed energy per unit volume and mass in case of max. impact compression load is higher than that of static load. But the absorbed energy per unit volume and mass shows that Al circular specimen is the best member. Especially, unlike max. compression loan, the absorbed energy per unit volume and mass in impact test turns out the low value.

• 한국구조물진단유지관리공학회 논문집
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• 제9권2호
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• pp.129-136
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• 2005

교량의 안전진단 과정에서 안전성 평가를 위해 전면교통통제 하에 차량재하시험이 일반적으로 실시된다. 교통통제의 단점을 개선시킨 최근에 제안된 의사정적재하시험에서는 계측된 시간이력 데이터 중 자유진동 부분을 퓨리에변환시켜 고유진동수를 구한다. 이렇게 구해진 고유진동수에는 분석기법에 따른 오차가 포함되며, 자유진동 데이터의 획득에도 다소 애로사항이 따른다. 이 연구에서는 Morlet wavelet를 모웨이블렛으로 하는 웨이블렛변환을 의사정적재하시험으로 계측한 데이터에 적용하여 구한 고유진동수와 감쇠율이 신뢰성을 가지며, 이 분석기법이 의사정적재하시험에 의한 차량재하시험의 자료 분석에 적용 가능하고 타당성이 있음을 보인다.

• 한국안전학회지
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• 제15권4호
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• pp.20-27
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• 2000

The hat shaped section members, spot welded strength resisting structures are the most energy absorbing ones of automobile components during the front-end collision. Under the static axial collapse load in velocity of 10mm/min and quasi-static collapse load in velocity of 1000mm/min, the collapse characteristics of the hat shaped section and double hat shaped section member have been analyzed by axial collapse tests with respect to the variations of spot weld pitches on the flanges. In addition, the quasi-static collapse simulations have been implemented in the same condition to the experiment's using FEM package, LS-DYNA3D. The simulated results have been verified in comparison with these from the quasi-static axial collapse tests. With the computational approaches the optimal energy absorbing structures can be suggested. Simulations are so helpful that the optimized data be supplied in designing vehicles in advance.

• Composites Research
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• 제22권2호
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• pp.24-29
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• 2009

본 연구에서는 알루미늄 허니컴 코어와 카본 면재가 적용된 샌드위치 복합재 구조에 대해 준정적 압입 손상 이후의 잔류 강도 평가에 대한 연구를 수행하였다. 3점 굽힘 시험과 압축 시험을 통해 시편의 강도를 확인하고 시편에 손상을 모사하기 위하여 준정적 압입 손상을 가하였다. 손상된 시편을 손상 전 시편과 동일한 시험을 통해 손상 전의 강도와 비교하였다. 압입 손상 이후 압축 강도와 굽힘 강도는 압입 깊이의 증가에 따라 강도가 감소하였고 손상 단계에 따른 잔류 강도 정도를 확인하였다.

• 한국지진공학회논문집
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• 제6권2호
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• pp.21-28
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• 2002

Ductile behavior and strength of concrete-filled steel(CFS) piers was supported by many quasi-static cyclic loading tests. This test method, however, only estimates the member′s deformation capacity under escalating and repetitive displacement and ignores dynamic and random aspects of an earthquake load. Therefore, to understand complete seismic behavior of the structure against an earthquake, dynamic tests such as shaking table test and pseudo-dynamic tests are required as well as quasi-static tests. In this paper, following "Seismic Performance of Concrete-Filled Steel Piers Part I : Quasi-Static Cyclic Loadint Test", the seismic behavior of CFS and steel piers designed for I-Soo overpass in Seoul in investigated by the pseudo-dynamic test. In addition, the residual strength of both piers after an earthquake is estimated by the quasi-static test. The results show that both piers have satisfactory ductility and strength against well-known EI Centro earthquake although the CFS pier has better strength and energy dissipation than the steel pier.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.2073-2079
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• 2008

This study aims to investigate the residual strength of sandwich composites with Al honeycomb core and carbon fiber face sheets after the quasi-static indentation damage by the experimental investigation. The 3-point bending test and the edge-wise compressive strength test were used to find the mechanical properties. The quasi-static point load and damaged hole was applied to introduce the simulated damage on the Each damaged specimens were finally assessed by the 3-point bending test and the compressive strength test. The investigation results revealed the residual strength of the damaged specimens due to the quasi-static indentation.

• 한국공간정보시스템학회:학술대회논문집
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• 한국공간정보시스템학회 2004년도 춘계 학술발표회 논문집 제1권1호(통권1호)
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• pp.245-251
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• 2004

This paper discuss the conditionally sampled actual wind pressure distributions causing peak quasi-static wind loads in the large span roofs using the wind pressures at many locations on dome models measured simultaneously in a wind tunnel. The actual extreme pressure distributions are compared itk load-response-correlation (LRC) method and the quasi-steady pressure distributions. Based on the results, the reason for the discrepancy in the LRC pressure distribution and the actual extreme pressure distribution are discussed. Futhermore, a brief discussion is made of the equivalent static wind load estimation for the large span roofs.

• 대한기계학회논문집
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• 제17권10호
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• pp.2555-2562
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• 1993

In this paper, the axial crush of the rectangular STS304 tube is analyzed using DYNA3D, and 10 models are tested under quasi-static load. The deformed shapes of analysis and test are present, and the analysis results are compared with the results of quasi-static test. This paper describes that free rotational boundary condition causes a very similar deformed shapes to expermental results, and using the elastic buclking modes as initial imperfecion shapes, the deformed shapes are very close to the experimental shapes.