• Journal of Korean Society of Steel Construction
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• v.17 no.1 s.74
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• pp.33-43
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• 2005

This paper presents the test results and evaluations for the energy dissipation capacity and compressive performance of light-weight hybrid panels. A total of 26 full-scale specimens of light-weight hybrid panels were tested. The parameters include the presence of light-weight foamed mortar, the specific gravity of light-weight foamed mortar (0.6, 0.8, 1.0, 1.2), the finishing materials (light-weight foamed mortar, OSB [Oriented Strand Board], gypsum board), the shape of bracing (x, ~), and the size of panels (1P-900 mm 2,400 mm, 2P-1,800 mm 2,400 mm). The results of the cyclic tests are somewhat different from those of monotonic tests, due to the different specific gravity of light-weight foamed mortar. It was found from the compressive tests that the ultimate strength and initial stiffness are increased by means of light-weight foamed mortar (2~2.5 times in ultimate strength and 2~3 times in initial stiffness).

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2017.06a
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• pp.192-193
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• 2017

본 논문에서는 비디오 영상 압축 왜곡 제거를 위해 Generative Adversarial Network (GAN)을 적용한 컨벌루션 뉴럴 네트워크 (CNN) 모델을 제안한다. GAN 모델의 생성 모델 (Generator)은 노이즈가 아닌 High Efficiency Video Coding (HEVC)로 압축된 영상을 입력 받은 뒤, 압축 왜곡이 제거된 영상을 출력하며, 분류 모델 (Discriminator)은 원본 영상과 압축된 영상을 입력 받은 뒤, 원본 영상과 압축 왜곡이 포함된 압축된 영상을 분류한다. 분류 모델은 5 개 층을 쌓은 컨벌루션 뉴럴 네트워크 구조를 사용하였고, 생성 모델은 5 개 층을 쌓은 SRCNN 구조와 VDSR 구조를 기반으로 한 두 개의 모델을 이용한 실험을 통해 얻은 결과를 비교하였다. 비디오 영상 압축 왜곡 제거 실험을 위해 원본 비디오 영상을 HEVC 을 이용하여 2Mbps, 4Mbps 로 압축된 영상을 사용하였으며, 압축된 영상 대비 왜곡이 제거된 영상을 얻을 수 있었다.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2016.11a
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• pp.319-321
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• 2016

본 논문에서는 지반함몰이 발생한 현장에 긴급복구를 위한 팽창기능제의 개발에 대한 내용이다. 현재 유동화토에 대한 기준이 없어 공동에 채워지는 채움재와 비슷한 압축강도인 0.3MPa을 기준으로 하여 흙의 일축압축시험 방법을 이용하여 실험을 진행하였다. 팽창기능제의 최적배합 실험과 팽창률에 따른 압축강도를 측정하여 뒤채움재로써의 기능 특성을 평가하였다. 실험결과, 팽창기능제 A의 경우 팽창률 750%이하에서 팽창기능제 B의 경우는 모든 실험체에서 목표 강도를 만족하였다.

• Journal of the Earthquake Engineering Society of Korea
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• v.5 no.2
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• pp.73-82
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• 2001

본 연구는 실험적 방법과 해석적 방법을 통하여 반복하중을 받는 ├형 철근콘크리트 접합부의 전단특성을 파악함을 목적으로 한다. ├형 접합부는 고강도 재료의 사용으로 인한 체적의 감소 뿐만 아니라, 지진발생 시 반복하중의 작용으로 인한 변동축력 등으로 , 구조적으로 취약한 부분이 될 가능성이 있다. 따라서 본 연구에서는 ├형 접합부의 전단특성을 파악하기 위하여 기동축력, 콘크리트 압축강도, 접합부 전단보강근비를 변수로 한 12개의 실험체를 제작하여 가력실험을 수행하였다. 또한, 유한요소 해석을 수행하여 본 실험결과와의 비교 검토를 통하여 타당성을 검토한 후, 기둥축력과 콘크리트 압축강도의 변화에 대한 변수해석을 통하여 접합부의 전단강도에 미치는 변수는 영향을 파악하였으며, 실험에 의한 실험체의 전단내력을 기존에 제안된 AIJ, ACI 규준 등과 비교 검토하였다. 본 연구의 결로부터 기둥축력과 콘크리트 압축강도가 ├형 철근콘크리트 접합부의 전단강도에 미치는 영향을 확인하였다.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.1081-1084
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• 2008

Column specimens were constructed with main parameters significantly affecting the strength of the compression lap splice, such as lap length, spacing of lapped bars, amount and location of transverse reinforcements, and concrete strength. An experimental study has been conducted with column specimens in concrete strength of 40 to 60 MPa. Diameters of lapped reinforcing bars are 22 mm. An axial load was monotonically applied to the column specimens. All specimens failed in a brittle sudden manner and cover concrete was blasted out at maximum load. Compression lap splice strengths of specimens were evaluated from strains measured at the beginning of the lap length. Effects of the main parameters on the strengths of compression lap splice are assessed. Similarly to strengths of tension lap slice, the compression splice strength is found to be affected by lap length, spacing of lapped bars, transverse reinforcements.

• Journal of the Korea Concrete Institute
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• v.28 no.2
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• pp.213-221
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• 2016

Uniaxial compression tests for ultra-high performance hybrid steel fiber reinforced concrete (UHPC) were performed to evaluate the compressive behavior of UHPC. The UHPC for testing contains hybrid steel fibers with a predetermined ratio using a length of 19 mm and 16 mm straight typed steel fibers. Test parameter was determined as a fiber volume ratio to investigate the effect of fiber volume ratio on the strength and secant modulus of elasticity. Test results showed that the compressive strength and elastic modulus of UHPC increased with increasing the fiber volume ratio. Based on the test results, the compressive strength and modulus of elasticity equations were proposed as function of the compressive strength of unreinforced and fiber reinforced UHPC, respectively. The simplified equations for predicting the mechanical properties of the UHPC were a good agreement with the test data. The proposed equations are expected to be applied to the SFRC and UHPC with steel fibers.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.11a
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• pp.37-38
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• 2020

본 연구에서는 홀로그램을 현대의 멀티미디어로써 효율적으로 사용하기 위해 필요한 홀로그램 압축 실험으로써 위상 홀로그램에 대한 압축 실험을 진행하였다. 포인트 클라우드로부터 생성한 여러 시점의 정보로 비디오 홀로그램을 생성하였다. 압축실험에선 원래의 홀로그램과 위상 펼침(Phase unwrapping) 방법을 통해 변환된 홀로그램을 비교하며, 동일한 압축률에선 심각한 성능하락은 없었으며, 동일한 QP(Quantization parameter)에선 더 높은 압축률을 보였다.

• Journal of Korean Society of Steel Construction
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• v.21 no.3
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• pp.311-320
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• 2009

This paper presents the experimental results of an experiment on the current rectangular CFT columns and rectangular CFT columns additionally confined by carbon fiber sheets(CFS) under axial loading. The main experimental parameters were the layer numbers of the CFS and the depth-to-thickness ratio. Nine specimens were prepared according to the experimental parameter plans, and axial compression tests were conducted. From the tests, the failure procedure, the load-axial deformation curve, the maximum axial strength, and the deformation capacity of the CFT columns and the confined CFT columns were compared. Finally, it was seen that the maximum axial strengths of the CFT increased more significantly than that of the current CFT columns because of delayed local buckling.

• Journal of Korean Society of Steel Construction
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• v.23 no.2
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• pp.229-236
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• 2011

This study was conducted to understand the characteristics of the compression behavior of steel plate-concrete(SC) structures with a width-to-thickness ratio under axial loading. SC structures are structural systems where concrete is poured into steel plates to which headed stud bolts had been attached inside. The specimens were classified according to the two width-to-thickness (W/T) ratios of 1.60 and 3.56. Through these experiments, the following conclusions could be arrived at. The fracture pattern of the specimens showed that steel plate buckling occurred between the stud lines, and that a crack occurred at the concrete spalling from the sides of the concrete before the system reached the maximum compressive strength. The maximum compressive strength of the specimens was larger than that of the existing equations (AISC 2005, ACI 318-05, and KBC 2005). With the increased W/T ratio of the specimens, the strength of the concrete core was decreased to account for the confinement effects from the steel plates.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.6
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• pp.33-40
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• 2021

Measuring the compressive strength of concrete is a very important factor in the safety review of concrete structures. Concrete compressive strength measurement methods include destructive and non-destructive methods. The destructive method includes the uniaxial compression failure method, and the non-destructive method includes the rebound hardness method and the elastic wave measurement method. In this study, the type of measurement method and the effect of reinforcing bars inside the concrete were tested to examine the relationship between them. Regardless of the type of specimen, the average compressive strength by the elastic wave measurement method among the three experimental methods was greater than the average compressive strength by the other methods. When the specimen type is the same, the standard deviation of the measured values of the elastic wave measurement method is smaller than that of the other measurement methods, so it can be seen that the elastic wave measurement method does not show large variance in the measured values compared to the other two measurement methods. When the average compressive strength according to the test method for each specimen was compared with the average compressive strength of the compressive failure test method, the average compressive strength was measured to be high in the order of the elastic wave measurement method, the compression failure test, and the rebound hardness method. Since the measured values of the compressive strength of concrete are different depending on the method of measuring the compressive strength of concrete and the presence or absence of reinforcing bars inside the concrete, further research is required considering the effect of various concrete covers.